500 • JAOA • Vol 102 • No 9 • September 2002Gaetano and Gaetano • Case report
Delayed closure of the anterior fontanelle is often associ-
ated with significant disease entities. Range of normal
closure of the anterior fontanelle is 4 to 26 months.
Increased intracranial pressure, hypothyroidism, and
skeletal anomalies are common etiologic factors. History,
physical examination, and diagnostic testing rule out most
disorders. Once these disorders have been ruled out, it is
important for the physician to realize that a persistent
open anterior fontanelle beyond the accepted ranges of
closure can be a normal outlier.
(Key words: case report, pediatrics, family medicine,
open anterior fontanelle)
examinations on thousands of children worldwide. As we
know through our medical education and clinical experi-
ence, children attain many physical milestones throughout
their development. Physicians use these physical milestones
to assess the health and well-being of their young patients and
regard variations from normal accepted ranges as red flags
that can indicate a disease process.
Palpation of the anterior fontanelle is an integral part of
any well-child examination. Much information can be gained
from this simple maneuver. Closure of the anterior fontanelle
is an important physical milestone that indicates a child’s
well-being. The range of normal closure is between 4 and 26
months.1Delayed closure of the anterior fontanelle can be
associated with many disease processes; however, careful
review of the literature reveals that once these specific disease
processes have been ruled out, delayed closure can be a
normal finding.1The purpose of this report is to familiarize
physicians with those etiologic factors commonly associated
with delayed closure of the anterior fontanelle. A review of
the workup to rule out these entities will be provided, and
we will show that once common diseases have been ruled
out, a persistent open anterior fontanelle can be a normal
ell-child care is an important aspect of pediatrics and
family medicine. Each day, physicians do physical
S.D. is a 32-month-old African American boy who pre-
sented to our clinic for a well-child physical examination.
He had no specific complaints at the time of presentation, and
his examination was essentially unremarkable except for the
finding of an open anterior fontanelle measuring 3 cm ?1.5
cm. This was noted to be an unusual finding considering
the patient’s age.
S.D. was born to a 21-year-old gravida II para I African
American woman at term gestation. His mother’s prenatal
course had been uncomplicated. Similarly, her previous preg-
nancy was without complication. At birth, S.D. weighed 3019
g, was 49 cm long, and had a head circumference of 36 cm—
all appropriate for gestational age. Routine plotting on a
standard growth curve chart for newborn males revealed
that he was at the 50th percentile for weight and head cir-
cumference, and at the 25th percentile for height. Physical
examinations done at the time of birth and at discharge from
the hospital all were within normal limits. Routine newborn
laboratory work including hematocrit, glucose, total bilirubin,
and metabolic screen also was unremarkable. S.D. had no
known family history of any metabolic, endocrine, or dys-
S.D. continued to routinely follow up in our clinic. He
received all of his immunizations at the appropriate intervals
as well as a screening hematocrit and lead level at 1 year.
His medical history is only remarkable for several bouts of
bronchiolitis, periodic exacerbations of reactive airway disease,
and one hospitalization at 6 months for pneumonia.
Throughout the course of his well-child examinations,
S.D.’s head circumference continued to plot at the 50th per-
centile, his weight remained at the 50th percentile, and his
height at the 25th percentile. He has always met all mile-
stones for motor, language, and social skills per routine
Denver developmental screening. He has never had any dys-
morphic features, nor has he been exposed to drugs or toxins.
At S.D.’s initial visit, the fontanelle was neither bulging
nor pulsatile. As this was a peculiar finding in a 32-month-
old child, a simple skull series was obtained to rule out under-
lying pathology. The skull films depicted the open fontanelle
as well as possible diastasis of the coronal sutures. A com-
puted tomographic (CT) scan of the head was recommended
to rule out causes of increased intracranial pressure.
S.D. was admitted to the hospital for sedation before
the head CT scan to obtain an optimal study. Laboratory
Persistent open anterior fontanelle in a healthy 32-month-old boy
HILDA M. DE GAETANO, DO
JOSEPH S. DE GAETANO, DO
From Nova Southeastern University College of Osteopathic Medicine in Ft Laud-
erdale, Florida, where Dr Joseph De Gaetano is assistant professor of family
medicine and Dr Hilda De Gaetano is clinical assistant professor of pediatrics.
Address correspondence to Joseph De Gaetano, DO, Nova Southeastern
University College of Osteopathic Medicine, 3200 S University Dr, Ft Lauderdale,
JAOA • Vol 102 • No 9 • September 2002 • 501
Gaetano and Gaetano • Case report
work to include a screening urinalysis, complete metabolic
profile, complete blood count, and thyrotropin was ordered
in an effort to rule out metabolic as well as endocrine etiologic
factors. The CT scan revealed the open fontanelle; however,
no pathologic intracranial processes were noted. Simultane-
ously, all laboratory work returned with normal values.
Potentially deleterious causes of persistent open anterior
fontanelle were ruled out. S.D. was discharged after his par-
ents were reassured that his physical examination finding
was a variant of normal and that closure would eventually
Persistent open anterior fontanelle can be a common
finding in children. This normal variant must be recognized,
given the vast number of well-child examinations done annu-
In 1949, Milton Aisenson, MD, reviewed the records of
two child health stations of the New York City Department
of Health for over 10 years to determine the normal age at
which the anterior fontanelle closes. Examinations of 1677
infants were recorded to note the age of closure of the ante-
rior fontanelle. The range of closure was determined to be
between 4 and 26 months.2Ninety percent of the children’s
fontanelles closed between 7 and 19 months, and 42% of the
fontanelles closed before 1 year.2This study set the guidelines
by which we examine our infant patients and counsel their
parents about the closure of the anterior fontanelle.
Delayed closure of the anterior fontanelle can be associ-
ated with multiple diseases, most of which have dysmor-
phic features that should facilitate early recognition.3Simple
radiographic or laboratory studies rule out other common
causes. Increased intracranial pressure is the most common
cause of delayed closure of the anterior fontanelle.3Multiple
etiologic factors are responsible for this phenomenon. Hydro-
cephalus, subdural hematomas, porencephalic cysts, and
tumors are most frequently seen. All are easily and routinely
identifiable via plain skull series or CT scanning of the head.
Many skeletal disorders are responsible for delayed clo-
sure of the anterior fontanelle. Achondroplasia, osteogen-
esis imperfecta, vitamin D deficiency–rickets, and cleidocra-
nial dysostosis are the most common of these.3These diseases
present with characteristic physical findings and are con-
firmed by associated laboratory and x-ray abnormalities.
Chromosomal defects as well as dysmorphogenetic syn-
dromes also predispose infants to delayed closure of the
anterior fontanelle. Down, trisomy 13, trisomy 18, Russell-
Silver, Rubinstein-Taybi, and Robinow’s syndromes com-
monly encompass this physical finding within the constel-
lation of findings associated with that particular syndrome.
All are routinely identified early in child development as
the result of their significant dysmorphic features.
Endocrine disorders as well as drug and toxin exposure
are also associated with delayed closure of the anterior
fontanelle. Commonly, hypothyroidism, fetal hydantoin syn-
drome, aminopterin-induced malformations, and aluminum
toxicity can all be associated with a persistent open fontanelle.
These also are easily ruled out via a thorough history, blood
levels, and thyroid function screening. All of the previously
mentioned disease processes had been sufficiently ruled out
via the multiple histories, physical examinations, x-rays, and
laboratory studies that S.D. had undergone since birth. The
significance of a persistent open anterior fontanelle in an oth-
erwise healthy 32-month-old child remained to be deter-
A search of the literature yielded few results. One source1
stated that in a healthy child with a persistent open fontanelle
who has continued to plot accordingly on growth charts, the
finding is considered an outlier with no specific significance.
Yet another source4stated that as long as a child’s head cir-
cumference progresses along a normal curve and the neu-
rologic and ocular fundoscopic examinations yield normal
results, no further diagnostic studies are required.
The persistent open fontanelle probably has a familial
inheritance pattern associated with it. Closure simply occurs
at a time beyond the accepted range of normal. The impor-
tance of recognizing the many etiologic factors responsible for
a persistent open anterior fontanelle is crucial for physicians
who care for children. Physicians must know the multiple syn-
dromes, diseases, and toxic exposures that can cause a delayed
This case report and literature review demonstrate that
once simple laboratory studies and x-rays are performed
and the previously mentioned maladies are ruled out, a per-
sistent open anterior fontanelle can be a normal finding. This
carries tremendous clinical relevance as we counsel our
patients’ parents about the ramifications of this discovery. Par-
ents can be told that there is probably a familial inheritance
associated with delayed closure of the anterior fontanelle
and that with time the fontanelle should close.
1. Tunnessen WW Jr. Persistent open anterior fontanelle. JAMA. 1990;264:2450.
2. Aisenson MR. Closing of the anterior fontanelle. Pediatrics. 1949;6:223-225.
3. Tunnessen WW Jr. Signs and Symptoms in Pediatrics. Philadelphia, Pa: JB
4. Popich GA, Smith DW. Fontanelles: Range of normal size. J Pediatrics.