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ORIGINAL ARTICLE
Reverse cascade screening of newborns for hereditary
haemochromatosis: a model for other late onset diseases?
E Cadet, D Capron, M Gallet, M-L Omanga-Le´ke´, H Boutignon, C Julier, K J H Robson, J Rochette
...............................................................................................................................
See end of article for
authors’ affiliations
.......................
Correspondence to:
Professor J Rochette,
Department of Medical
Genetics and UMR-INERIS,
Centre Hospitalo-
Universitaire et Faculte´de
Me´decine, 3 rue des
Louvels, 80036, Amiens,
France; jacques.rochette@
u-picardie.fr
Received
17 September 2004
Revised 8 December 2004
Accepted
13 December 2004
.......................
J Med Genet 2005;42:390–395. doi: 10.1136/jmg.2004.027284
Background: Genetic testing can determine those at risk for hereditary haemochromatosis (HH) caused by
HFE mutations before the onset of symptoms. However, there is no optimum screening strategy, mainly
owing to the variable penetrance in those who are homozygous for the HFE Cys282Tyr (C282Y) mutation.
The objective of this study was to identify the majority of individuals at serious risk of developing HFE
haemochromatosis before they developed life threatening complications.
Methods: We first estimated the therapeutic penetrance of the C282Y mutation in people living in la
Somme, France, using genetic, demographic, biochemical, and follow up data. We examined the benefits
of neonatal screening on the basis of increased risk to relatives of newborns carrying one or two copies of
the C282Y mutation. Between 1999 and 2002, we screened 7038 newborns from two maternity hospitals
in the north of France for the C282Y and His63Asp (H63D) mutations in the HFE gene, using bloodspots
collected on Guthrie cards. Family studies and genetic counselling were undertaken, based on the results
of the baby’s genotype.
Findings: In la Somme, we found that 24% of the adults homozygous for the C282Y mutation required at
least 5 g iron to be removed to restore normal iron parameters (that is, the therapeutic penetrance). In the
reverse cascade screening study, we identified 19 C282Y homozygotes (1/370), 491 heterozygotes
(1/14) and 166 compound heterozygotes (1/42) in 7038 newborns tested. The reverse cascade
screening strategy resulted in 80 adults being screened for both mutations. We identified 10 previously
unknown C282Y homozygotes of whom six (four men and two women) required venesection. Acceptance
of neonatal screening was high; parents understood the risks of having HH and the benefits of early
detection, but a number of parents were reluctant to take the test themselves. Neonatal screening for HH is
straightforward. Reverse cascade screening increased the efficiency of detecting affected adults with
undiagnosed haemochromatosis. This strategy allows almost complete coverage for HH and could be a
model for efficient screening for other late onset genetic diseases.
Hereditary haemochromatosis (HH) caused by mutations
in HFE is a common autosomal recessive disorder of
iron metabolism in people of northern European
extraction. Often, middle aged patients present with early
clinical symptoms of general fatigue, arthralgia, and arthritis,
which are not specific to HH. Liver disease, diabetes, and
impotence are complications that arise later.
1
In northern
France, about 85% of patients with HH are homozygous for
the Cys282Tyr (C282Y) mutation in HFE.
2
The role of a
second mutation, the substitution of histidine by aspartic
acid at position 63 (H63D) is unclear.
3
There are a number of
arguments favouring preventative screening for haemochro-
matosis in northern European populations: (a) 2–5 of every
1000 individuals in the North of Europe are homozygotes for
the C282Y mutation (genotype HH/YY), (b) normal life
expectancy can be restored if iron is removed by venesection
in the pre-cirrhotic stage; and (c) premature death results if
HH remains undetected for too long.
4
Despite the fact that
HH can be considered as a model genetic disorder for
screening and disease prevention, there is no consensus
regarding the optimal screening strategy.
5–7
The challenge is
how to identify the majority of individuals at serious risk of
developing iron overload before they develop life threatening
complications.
The diagnostic utility of a single measurement of iron
status, (such as percentage transferrin saturation (%T
sat
)or
unbound iron binding capacity test) varies with the age of
testing.
89
Disease is accompanied by increased serum ferritin
levels, which unfortunately are also associated with a
number of other conditions. Repeated biochemical testing is
recommended, but this is costly.
710
Although men show signs
of the disease earlier than women, there is a wide age range
associated with the onset of symptoms in both sexes.
11
For
these reasons, the optimum age for screening adults using
serum iron parameters has yet to be established.
Genetic screening is an alternative but it raises ethical,
political, and economic issues. In particular, the incomplete
penetrance of the C282Y mutation in homozygotes raises
problems as to the definition of the disease and when to
treat.
12–17
Other genotypes are occasionally associated with
the disease.
18
There are a number of reports describing low
levels of clinical penetrance in C282Y homozygotes.
15 17
These
findings in particular have suggested that it is not cost
effective to undertake population screening for haemochro-
matosis. On the other hand, there are other reports
suggesting that there are much higher levels of mutation
penetrance elsewhere.
19
Should the definition of penetrance
depend upon abnormal biochemical parameters or should it
also include clinical disease? One of the main reasons for
instigating a screening programme for haemochromatosis is
that disease prevention and hence, any screening strategy,
needs to identify patients in the early pre-clinical phase
before irreversible end organ damage has occurred. If
widespread population screening is to be cost effective for
Abbreviations: CF, cystic fibrosis; HH, hereditary haemochromatosis;
PKU, phenylketonuria
390
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haemochromatosis, it is important to understand the nature
of disease penetrance in that particular population.
If the degree of penetrance is high, then this provides a
justification for some form of population screening. Genetic
screening is not age dependent and could be particularly cost
effective if it could be incorporated with DNA screening for
other diseases such as cystic fibrosis (CF). The ability to
follow a cohort over time and see if and when the members
develop clinical disease will also help in understanding
penetrance in haemochromatosis when presentation is so
variable. Another advantage of a neonatal screening pro-
gramme for haemochromatosis is that it also permits the
application of reverse cascade screening.
Cascade screening is used to identify asymptomatic
individuals who are at risk of developing a disease because
they have an affected relative. Reverse cascade screening
identifies the asymptomatic individual first and uses this
information to identify undiagnosed affected relatives.
We analysed the number of C282Y homozygotes identified
in the Somme de´partement of France over a 4 year period,
and identified those who required the removal of more than
5 g of iron by quantitative phlebotomy, using the iron burden
to define therapeutic penetrance. In a population in which
50% of C282Y homozygotes express disease, then 40% of
homozygotes should be detected by screening first to third
degree relatives of C282Y homozygotes.
20
On the other hand,
if penetrance is lower, with 25% of the C282Y homozygotes
showing signs of iron burden, the number of at risk
individuals detected by reverse cascade screening falls to
24%.
20
This then reduces the number of people to be tested to
identify a single at risk individual.
Therefore, as an alternative to phenotypic screening, we
investigated the advantages of neonatal screening for HH
followed by screening for the variants in parents and other
relatives when the neonate was identified as heterozygous or
homozygous for the at risk genotype (that is, ‘‘reverse’’
cascade screening). The advantage of this strategy is that it
identifies a target population of relatives who have an
increased risk of HH.
MATERIALS AND METHODS
Penetrance of the C282Y homozygous genotype in the
adult population
Available data regarding the Somme district were extracted
from the Institut National des Statistiques et des E
´tudes
E
´conomiques and from the Institut National des E
´tudes
De´mographiques, Paris, France. We estimated the penetrance
of the C282Y mutation during the period 1996–2000 using
demographic, biochemical, genetic, and phlebotomy records
in patients having the HH/YY genotype in our de´partement.
We defined a fully penetrant genotype as one requiring the
removal of a minimum of 5 g of iron to return serum iron
parameters to normal. Using this information, we instigated
a neonatal screening study for HH.
Neonatal study design
Both local and national ethics permission were obtained,
with the following qualifications: the national ethics com-
mittee asked that all parents should have access to their
child’s results, and the local research ethics committee
restricted the length of the study to 3 years. The work was
approved by the Ministry of Health (registered no. DGS 2002/
0366) and insured as required for research programmes
involving genetic testing of no immediate benefit
(Biomedicinsure no. 200300035; Gerling Co., France). This
insurance policy protects the hospital against claims of
negligence that might be filed at a later date by the parents.
Neonatal screening was conducted at two maternity
hospitals in Picardie (northern France, including the
Somme de´partement) between 1999 and 2002. Medical staff
(paediatricians and nurses) attended a series of seminars on
neonatal screening and HH with 6 monthly updates.
When each baby was 1 day old, parents were given a four
page leaflet describing the genetics of HH and its complica-
tions, supplemented on the second day by verbal information
including a question and answer session. The time taken
(5–30 minutes) depended on the parents’ understanding of
genetics. Participation in the programme was entirely
voluntary, with a clear explanation that the results of the
screen would initially benefit parents and relatives.
Implications of the at risk genotype (HH/YY) and its
ramifications for their baby were explained to parents.
Consent was modified as new genes involved in haemo-
chromatosis were described. Initially, however, it was made
clear to parents that screening was restricted to the C282Y
and H63D mutations in the HFE gene and that the study did
not include a test for neonatal haemochromatosis. Parents
were given 2 days to accept or refuse the genetic test for their
baby. When informed consent from both parents was
obtained, on the third day after birth blood was spotted onto
a Guthrie card that forms part of the routine screening for
phenylketonuria (PKU), hypothyroidism, and CF. Local
general practitioners and paediatricians practising in the
private sector also received written information from the local
social security system concerning this 3 year research
programme for HH neonatal screening. Three annual
continuing medical education conferences on haemochro-
matosis, its management, and reverse cascade screening were
organised in the medical school for all local clinicians.
Genetic studies
DNA was extracted from a Guthrie card spot with the
QIAamp Blood kit (Qiagen SA, Courtaboeuf, France) using
the specified protocol for dried blood. As previously
described,
21 22
10 ml of the eluted DNA (75–100 ng) were
used for genotyping the C282Y and H63D mutations with
appropriate controls.
We calculated allele and genotype frequencies for both
mutations in neonates. Expected genotype frequencies were
estimated according to the Hardy-Weinberg equilibrium. We
performed x
2
tests to verify Hardy-Weinberg equilibrium for
all genotypes and to compare genotype and allele frequencies
in different groups.
Parents received the results through the post and were
invited in for free genetic counselling if their newborn had
the genotype HH/YY. They were informed that, although the
HH/YY genotype was a risk factor for developing iron
overload in later life, it did not affect the health of the baby,
but that family screening was advisable. If there was no
response, the parents received a second letter and if there was
no reply to this, a telephone call. The couples themselves were
responsible for informing other family members. Genetic
counselling was arranged at the request of the parents,
during which it was stressed that the baby did not need any
treatment or a special diet, but regular serum iron measure-
ments as an adult was advised. Transferrin saturation and
serum ferritin were not measured in the neonates.
RESULTS
The population of the Somme de´partement is 551 479, of
whom 84% are white. Using the Hardy-Weinberg equili-
brium, and knowing that C282Y allele has an allele frequency
in this part of France of q = 0.0577, we found that within the
white subset, about 1542 people are expected to be homo-
zygous for the C282Y mutation in the HFE gene.
723
Because
of age and sex dependency of the manifestations of the
symptoms, corrections were made using demographic data.
In the white population, 21.1% of the women are aged
Reverse cascade screening for haemochromatosis 391
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>45 years and 22.5% of the men are aged >35 years,
therefore we estimated that in this population 347 men and
325 women are C282Y homozygotes at risk of developing
symptoms for HH. From 1996 to 2000, 288 patients fulfilled
these age criteria and were identified as C282Y homozygotes
(176 men; 112 women). Of the men, 107 have had at least 5 g
of iron removed, giving a therapeutic penetrance of 30% (107/
347), while 54 women were treated, giving a therapeutic
penetrance of 16.6% (54/325). This gives an overall pene-
trance of 24% (161/672), a figure that, based on the
calculations of Krawzcak et al,
20
suggested that cascade
screening was likely to be effective.
To see whether reverse cascade screening would be a
potential and efficient screening strategy for haemochroma-
tosis, we used Laplace-Baye’s theorem to estimate the risk of
parents having the homozygous genotype (HH/YY) if their
child was either homozygous or heterozygous for the C282Y
mutation. Using an average Y allele frequency (q) already
known in the white population from previous studies
(q = 0.0577), corresponding to a prevalence of about 1/300,
we calculated that if an HH/YY newborn is identified, the
probability for each parent being HH/YY is q, which
corresponds to a relative risk of 1/q compared with the
general population—that is, they have a 17 fold greater risk.
In the case of a C282Y heterozygote, the probability of each
parent being HH/YY is q/2, corresponding to a relative risk of
1/2q, or an 8.5 fold greater risk compared with that of the
general population. Probability for both parents to be
homozygous for the C282Y mutation when a child is
homozygous is q
2
.
We then carried out a pilot study to estimate the take up
rate and to plan the logistics of neonatal screening study for
haemochromatosis. Of those who first received an explana-
tory leaflet about the HH screening programme in neonates,
85% (105/123) agreed to neonatal genetic testing and family
studies. Based on this result, we decided to organise neonatal
screening for HH in Picardie.
We screened 7038 of 8280 babies born during the study
period for the C282Y and H63D mutations. We identified 19
C282Y homozygous babies from 18 families; two were
brothers. Results for all genotypic groups for all ethnic
groups are presented in table 1. Of 7038 newborns tested, 694
(9.8%) had at least one non-white parent. There were no
C282Y homozygotes in this group. Frequency of the C282Y
allele in newborns with one or two non-white parents was
0.0200 compared with an allele frequency of 0.0526 in the
group in which both parents were white (p,0.001). The
H63D allele frequency was 0.140 in the neonates with one or
two non-white parents compared with 0.185 in the neonate
group in which both parents were white (p = 0.05). Genotype
frequencies for C282Y and H63D mutations followed Hardy-
Weinberg equilibrium for five genotypes but not for
compound heterozygotes (HD/CY) (p,0.001). This dis-
crepancy in HD/CY had also been observed in a previous
study of healthy adults from the same region.
23
Screening of families with C282Y homozygous
neonates
Of 18 couples, 11 registered for genetic counselling with
consent from both parents. Seven families did not respond to
the letters they were sent, nor did they contact any medical
staff. Counselling was performed 3–6 months after their baby
was identified as a C282Y homozygote. Screening of these 22
parents identified five family members from four different
families as C282Y homozygotes; in one family, the homo-
zygotes were a parent and the baby’s 7 year old brother, and
in each of the other three families it was a parent. None of
these families had a history of haemochromatosis.
Screening of families with C282Y heterozygous
neonates
Parents with a C282Y heterozygous baby could also request
family screening. In this group, only 10 of 657 couples
requested genetic testing. Five C282Y homozygotes from two
families were identified: one parent and an aunt in one
family; one parent, an uncle, and a grandmother in the other.
Again, there was no family history of haemochromatosis.
Iron status in family members identified as C282Y
homozygotes
A follow up was arranged for family members identified as
C282Y homozygotes. Baseline (T
0
)T
sat
and serum ferritin
levels were determined in all the 10 C282Y homozygotes with
a follow up measurement (T
1
) at 6 months (table 2). Subject
V was immediately treated by venesection in view of the high
T
sat
. Subject II, following a second biochemical (T
1
) estima-
tion 3 months later, had elevated T
sat
, and treatment was
recommended. After the second estimation, treatment was
recommended for subjects III, IV, VII, and IX. All these
patients had normal C reactive protein levels. Subject IX, a
woman aged 49 years, presenting with 88% T
sat
and a serum
ferritin of 100 was not treated originally, as her serum ferritin
fell within the normal range (50–200 mg/l). Subsequently her
serum ferritin has risen to 226 mg/l (table 2) and she is now
receiving treatment. In total, all of the four men and two of
the five women now require venesection. We aim to maintain
their serum ferritin at (50 mg/l and T
sat
levels at (25%. Of
the five HH/YY women, two women are being treated for
haemochromatosis. Further questioning revealed that indi-
viduals II and V had symptoms of asthenia. An xray analysis
showed a loss of joint space at metacarpophalangeal joints in
individual II. All the other individuals were symptomless.
Serum iron parameters in family members identified
as compound heterozygotes
There were 14 people (seven men, seven women; 10 of whom
were grandparents) from 11 families identified with the
genotype HD/CY. Only one, a grandfather (aged 50 years)
had an increased serum ferritin level (378 mg/l) with a
normal T
sat
(39%) on initial testing. Six months later, his T
sat
was 54% and serum ferritin 648 mg/l, following which one
400 mL venesection was performed; following venesection,
T
sat
and serum ferritin values were 25% and 150 mg/l,
respectively. Twelve months later, his serum iron parameters
remain within the normal range.
DISCUSSION
The penetrance of a genotype can be defined as the
proportion of individuals with that particular genotype who
Table 1 HFE genotypes among the neonate population
(all ethnic groups)
Genotype
Observed
(n = 7038) Expected p
HH/CC 4195 (59.61) 4173 (59.30) 0.6
HD/CC 1952 (27.74) 1962 (27.90) 0.76
HH/CY 491 (6.97) 531 (7.54) 0.07
DD/CC 215 (3.05) 230 (3.25) 0.35
HD/CY 166 (2.36) 125 (1.77) ,0.001*
HH/YY 19 (0.27) 17 (0.24) 0.61
Results are n (%). p value: x
2
analysis for all genotypes. Y allele frequency
is 0.0494, 95% CI 0.047 to 0.0548; D allele frequency is 0.181, 95% CI
0.172 to 0.190. Ethnic group was self reported. *Genotype frequencies
for C282Y and H63D variants were each in Hardy-Weinberg
equilibrium; however, increased frequency of double heterozygotes (HD/
CY) was observed owing to partial linkage disequilibrium (p,0.001)
between these variants.
392 Cadet, Capron, Gallet, et al
www.jmedgenet.com
have the associated phenotype. If these individuals then
present with clinical symptoms, this can then be regarded as
clinical penetrance. Based on questionnaire data or clinical
observation, the prevalence of symptoms associated with
haemochromatosis is common in both C282Y homozygotes
and individuals with the wildtype genotype. Therefore, the
clinical penetrance of the HH/YY genotype with regard to
these symptoms is low.
15 17
Biochemical penetrance, the
finding of increased serum iron indices, is much higher than
the clinical penetrance. Indeed, most C282Y homozygotes
display a common biochemical phenotype, namely an
elevated transferrin saturation level that is found with an
increased serum ferritin level in up to 77% of men and 56% of
women.
24
Heterogeneity in the presentation of HFE asso-
ciated haemochromatosis, together with the fact that
biochemical presentation is both age and gender specific,
present difficulties in comparing studies involving the HH/YY
genotype.
25
Because of this, the penetrance of the HH/YY
genotype has proved difficult to establish. Therefore, in our
study we took a different approach by examining therapeutic
penetrance, by referring it to the actual iron burden. The
assumption is that if a genetic disease is treated, thus
preventing complications, the genotype giving rise to the
disease is fully penetrant. Rather than waiting for massive
accumulation of iron, the demonstration of increased iron
stores was chosen as the indication for treatment. Although
different definitions cannot give rise to comparisons, the
removal of at least 5 g of iron in order to restore normal iron
biochemical parameters seems a useful definition of pene-
trance, particularly, as this has long been part of the
definition of the disease, yet more recent reports have not
considered this factor in describing what is and what is not
haemochromatosis.
In this study, we identified 288 of a possible 672
haemochromatosis patients who had first been referred to
consultants because they had high serum iron parameters
and/or clinical manifestations including arthralgia and/or
fatigue. If the definition of disease is based on quantitative
phlebotomy, the removal of 5 g of iron over a period of less
than a year (that is, the ‘‘therapeutic penetrance’’), 161
patients met this criterion, but 127 of the 288 C282Y
homozygotes did not. It is possible that among the remaining
predicted 384 C282Y homozygotes, some may have undiag-
nosed haemochromatosis, thus the observed therapeutic
penetrance of the HH/YY genotype of 24% (161/672) may
well be an underestimate. Nevertheless, in a population with
this condition, widespread population screening for haemo-
chromatosis may be advantageous.
Neonatal screening for HH has been undertaken by other
groups purely as a means of population screening to establish
the frequencies of the C282Y and H63D alleles.
26 27
Our
strategy combines population wide and reverse cascade
screening of C282Y homozygous newborns to enable early
detection of disease in parents and relatives. The neonatal
period is an excellent time to access family members of
different generations and arguably an ideal time to detect
early haemochromatosis, as the majority of the parents of the
newborns were ,35 years of age in this study.
Initially, this study was designed to screen for the C282Y
and H63D mutations where both parents were whites, but
was later expanded as universal screening at the request of
non-white parents. The percentage of newborns were missed
was 15%; 12% due to staff forgetfulness, and 3% to parents
declining the test. Thus, the acceptance rate for neonatal
screening for C282Y and H63D was high; the parents were
aware of the implications for themselves and their families.
Traditionally, population screening for haemochromatosis
has had no psychosocial impact on anxiety, mental health, or
physical health status.
28
Anxiety was never given as a reason
for refusal of neonatal screening, possibly because haemo-
chromatosis is treatable.
29
Both parents were unanimous in
their decision to accept or refuse neonatal testing. In France,
current law prevents disclosure of genetic testing results to
insurance companies, banks, or employers, and hence this is
unlikely to be a reason for refusal. To obtain a high
acceptance rate for genetic screening programmes elsewhere,
it may be necessary to enact local law to prevent disclosure of
genetic information to limit discrimination by insurance
companies, employers and banks. Currently, neonatal screen-
ing for PKU, hypothyroidism, haemoglobinopathies, and CF
does not require parental permission, as these are not DNA
based tests. However if a result justifies DNA analysis (for
example, in CF) parental consent is required.
Although acceptance of neonatal screening was high, only
11 of the 18 families (61%) with homozygous newborns
accepted further testing. The take up rate for further testing
in families with C282Y heterozygous babies was much lower
compared with those with homozygous newborns; only 10 of
657 families (1.6%) responded despite all the information
and support provided. In these families, increased personal
contact with parents might have increased the response
rate,
30
but this would have been time consuming, and
required more staff and resources. However, despite the poor
response, reverse cascade screening identified five C282Y
homozygotes from the 10 families with C282Y heterozygote
newborns. These results demonstrate that parents were
willing for their baby to be screened, yet unwilling to be
screened themselves. Our screening strategy benefits both
parents equally (table 2). A previous study showed that it was
difficult to recruit young men, the very group most likely to
benefit from screening programmes for HH.
31
If this lack of
willingness to participate in screening programmes is
prevalent among the adult population, it has wide implica-
tions for preventative screening in a wide range of diseases.
Screening for several diseases at once is the most cost
effective approach, and neonatal screening is the most cost
effective time. It also lends itself to the creation of a
centralised register, allowing longitudinal studies on disease
penetrance, not just for HH but also for other diseases that
might be incorporated later into disease surveillance
programmes.
Using this strategy of reverse cascade screening, we have
identified 10 previously unknown C282Y homozygotes, of
whom six (four men and two women) are now being treated
by regular venesection, thus preventing complications of the
disease and restoring normal life expectancy. Annual follow
ups have been proposed for the other three women who are
Table 2 Iron status in family members identified as
C282Y homozygotes
Subject
no. Sex
Age
(years)
T
sat
(%)
T
0
/T
1
Ferritin
(mg/l) T
0
/T
1
Amount
of iron
removed (g)*
IM7 39/42 190/220 NA
II M34 63/731430/68016.5
III M32 47/59 342/525 5.25
IV M`41 48/75 150/542 6.0
VM`24 79/ND 672/ND 6.5
VI F30 25/33 15/46 NA
VII F`27 78/89 137/634 5.5
VIII F23 10/22 12/55 NA
IX F`49 88/92 100/226 0.5
XF`27 65/68 32/82 NA
*To maintain to T
sat
(25% and ferritin (50 mg/l. Subject identified
through: C282Y homozygous newborn; `C282Y heterozygous
newborn. Transferrin saturation (T
sat
%) and serum ferritin (mg/l) at
genotyping (T
0
); T
1
is 6 months or 13 months past T
0
. NA, not applicable.
Reverse cascade screening for haemochromatosis 393
www.jmedgenet.com
C282Y homozygotes. Close monitoring has been proposed for
one individual, the 7 year old son of subject II (table 3),
whose serum ferritin rose by more than 20% in 1 year. Of 14
compound heterozygotes, one required treatment, despite the
mean (SD) age of this group being 49 (2.3) years.
It should be noted that all four HH/YY men identified in
this study had elevated serum iron parameters 1 year after
diagnosis. It is important to appreciate the significance of
raised serum iron parameters in the absence of clinical
disease. In particular, arthritis due to joint damage associated
with haemochromatosis is not always reversible.
32
It should
be noted that the youngest patient identified was aged
24 years and the oldest 49 years. Increased serum iron
parameters in one so young indicates that such individuals
are likely to develop haemochromatosis unless treated.
Therefore, our approach allows the early identification of
HH with the aim of preventing clinical disease. The large
number of relatives requiring treatment for haemochroma-
tosis suggests that our figure for therapeutic penetrance of
24% may well be an underestimate for this part of France.
This study raises several questions and issues. When do we
actually treat someone with HH/YY genotype with raised a
T
sat
% but normal ferritin levels? How often do we repeat
serum ferritin level measurements? It has also been ques-
tioned whether families with heterozygous newborns should
be investigated. An unexpected finding was the identification
of five homozygotes from 10 of such families, a number
similar to that identified through reverse cascade screening of
homozygous newborns. Although the number of such
families tested is low, it shows that enrichment in HH/YY
genotypes in families from heterozygous babies has to be
taken into account in a future screening strategy. All family
members diagnosed were very grateful for the early detection
of their haemochromatosis.
Reverse cascade screening offers the possibility of early
clinical intervention, preventing morbidity and mortality
associated with HH. Cost effective preventive measures
include regular blood donation and reduction of alcohol
intake. A major difficulty with any neonatal screening
programme is making sure that information is retained for
the future. Screening newborns is not just for the benefit of
their families, provided their genotypes are not lost. A register
is vital. Setting up a local haemochromatosis register could
play a key role in coordinating a multidisciplinary approach
to the management of patients, and facilitate family and
longitudinal studies for assessment of penetrance of the HH/
YY genotype. Childless couples are excluded in the initial
screening step, but may be screened through being a relative.
For reverse cascade screening to be successful, effective
genetic counselling and universally available medical infor-
mation sheets are vital.
In summary, reverse cascade screening for HH is very
effective in identifying previously unknown affected indivi-
duals. Reverse cascade screening from a neonate who is HH/
CY or HH/YY identified 10 homozygotes from 80 parents and
relatives (1/8), which is a high percentage compared with
random screening.
20
ELECTRONIC DATABASE INFORMATION
Accession numbers and URLs for data in this article:
Genbank, http://www.ncbi.nlm.nih.gov/Genbank/ (for haemo-
chromatosis gene (HFE)); and Online Mendelian Inheri-
tance in Man (OMIM), http://www.ncbi.nlm.nih.gov/omim/
(for HH (OMIM #235200)).
ACKNOWLEDGEMENTS
We thank all the medical staff in the participating hospitals
who helped collect the samples. We are indebted to Professor Sir
D Weatherall and Professor S Lay Thein for encouragement and
critical assessment of the manuscript.
Authors’ affiliations
.....................
E Cadet, J Rochette, Department of Medical Genetics & UMR-INERIS,
Centre Hospitalo-Universitaire et Faculte´deMe´decine, Amiens, France
D Capron, Department of Hepato-Gastroenterologie, Centre Hospitalo-
Universitaire et Faculte´deMe´decine, Amiens, France
M Gallet, M-L Omanga-Le´ke´, Department of Ne´onatalogie, Centre
Hospitalo-Universitaire et Faculte´deMe´decine, Amiens, France
H Boutignon, Department of Ne´onatalogie, Centre Hospitalier de
Compie`gne, France
C Julier, Institut Pasteur, Paris, France
K J H Robson, MRC Molecular Haematology Unit, Weatherall Institute of
Molecular Medicine, Oxford, UK
This work was funded by EC contract QLRT-1999-02237 and le Poˆle
Ge´nie Biologique et Me´dical, UPJV-UTC from Picardie
Competing interests: none declared
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