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Genetic counseling for fragile X syndrome: Updated recommendations of the National Society of Genetic Counselors

Duke University Medical Center, Durham, North Carolina 27710, USA.
Journal of Genetic Counseling (Impact Factor: 1.75). 09/2005; 14(4):249-70. DOI: 10.1007/s10897-005-4802-x
Source: PubMed

ABSTRACT These recommendations describe the minimum standard criteria for genetic counseling and testing of individuals and families with fragile X syndrome, as well as carriers and potential carriers of a fragile X mutation. The original guidelines (published in 2000) have been revised, replacing a stratified pre- and full mutation model of fragile X syndrome with one based on a continuum of gene effects across the full spectrum of FMR1 CGG trinucleotide repeat expansion. This document reviews the molecular genetics of fragile X syndrome, clinical phenotype (including the spectrum of premature ovarian failure and fragile X-associated tremor-ataxia syndrome), indications for genetic testing and interpretation of results, risks of transmission, family planning options, psychosocial issues, and references for professional and patient resources. These recommendations are the opinions of a multicenter working group of genetic counselors with expertise in fragile X syndrome genetic counseling, and they are based on clinical experience, review of pertinent English language articles, and reports of expert committees. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. The professional judgment of a health care provider, familiar with the facts and circumstances of a specific case, will always supersede these recommendations.

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    • "It is estimated that 1 in 157 females [Berkenstadt et al., 2007] and 1 in 755 males [Rousseau et al., 1996] are carriers of the pre-mutation. The current approach to identifying carriers of FXS is to offer genetic testing to individuals with a family history of FXS or undiagnosed intellectual disability [McConkie-Rosell et al., 2005; Sherman et al., 2005]. However, this approach is limited by issues around dissemination of genetic risk information in families [van Rijn et al., 1997] and its reliance on the diagnosis of an affected individual to make relatives aware of their risk. "
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    ABSTRACT: Population carrier screening for fragile X syndrome can provide women with information about their risk of having a child with fragile X syndrome and their risk of fragile X-associated primary ovarian insufficiency and fragile X-associated tremor ataxia syndrome. Few studies have explored women's decisions when offered carrier screening for fragile X syndrome. Interviews were conducted with 31 women who participated in a pilot study offering carrier screening to non-pregnant women. A qualitative approach was used to gain an in-depth understanding of women's experiences and examine their decision-making processes, including women who were tested and those who decided not to be tested. The decision-making process occurred in two phases. In the first phase, the participant's reproductive stage of life and experience with illness and disability were major factors influencing whether she would consider screening. In the second phase of decision-making, participants' perceptions of the value of knowing their carrier status was the most notable factor for influencing whether a woman actually had the carrier test. Some women appreciated having time for deliberation and those who were tested did not express regret about their decision. Our findings support offering carrier screening for fragile X syndrome to non-pregnant women and suggest that women from the general population will have specific informational and counseling needs when offered carrier testing. This study highlights the unique challenges encountered by women from the general population when making a decision about testing for fragile X syndrome carrier status and illustrates the importance of understanding how women make decisions.
    American Journal of Medical Genetics Part A 12/2009; 149A(12):2731-8. DOI:10.1002/ajmg.a.33122 · 2.05 Impact Factor
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    • "During the early development (0–5 years), most interventions appear to be helpful for children with FXS, including physical, speech, language and occupational therapy, and the promotion of a consistent routine for the child, which helps to reduce anxiety. A support for parents and siblings with family education and genetic counseling is important to facilitate the acceptance and understanding of individuals with FXS [McConkie-Rosell et al., 2005]. Despite the wealth of knowledge regarding the behavioral phenotype of FXS, there are almost no empirical studies on the effectiveness of behavioral treatments in patients with FXS that satisfy good research practice, e.g., a placebo-controlled behavioral intervention [Reiss and Hall, 2007]. "
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    ABSTRACT: Fragile X syndrome (FXS), a single gene disorder with an expanded CGG allele on the X chromosome, is the most common form of inherited cognitive impairment. The cognitive deficit ranges from mild learning disabilities to severe intellectual disability. The phenotype includes hyperactivity, short attention span, emotional problems including anxiety, social avoidance, poor eye contact, and hyperarousal to sensory stimuli. Imaging studies in FXS have clarified the impact of the FMR1 mutation on brain development and function by documenting structural abnormalities, predominantly in the caudate nucleus and cerebellum, and functional deficits in the caudate, frontal-striatal circuits, and the limbic system. On the basis of current research results, a targeted treatment for FXS will be available in the near future. Currently, a number of psychopharmacological agents are helpful in treating many of the problems in FXS including hyperactivity, attention deficits, anxiety, episodic aggression, and hyperarousal. Although the targeted treatments aim at strengthening synaptic connections, it is essential that these treatments are combined with learning programs that address the cognitive deficits in FXS.
    Developmental Disabilities Research Reviews 01/2009; 15(4):333-42. DOI:10.1002/ddrr.80 · 0.29 Impact Factor
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    • "For FraX, those who supported screening their own child strongly supported NBS (72%), and those who did not want to screen their own children were strongly opposed to NBS (84%). These responses represent two very distinct views on NBS for FraX, and the complex risks and benefits associated with this screening [Bailey, 2004; McConkie-Rosell et al., 2005]. Those who support NBS see potential for early intervention; those who oppose fear the risks of labeling and self-fulfilling prophecies [Cohen, 1998; Ross, 2002]. "
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    ABSTRACT: There is movement to expand newborn screening (NBS) to include conditions that challenge the traditional public health screening criteria. Little is known about the attitudes of genetic counselors towards expanding NBS and offering predictive genetic tests to children. For our study genetic counselors completed an internet survey posted on the National Society of Genetic Counselors Listserv regarding five conditions: cystic fibrosis (CF), Duchenne muscular dystrophy (DMD), glucose-6-phosphate dehydrogenase deficiency (G6PD), fragile X (FraX), and type 1 diabetes (T1D). The survey addressed attitudes towards: (1) testing high-risk infants; (2) mandatory NBS; (3) population screening beyond the newborn period; and (4) testing one's own child. Two hundred sixty-seven usable surveys were received. Over two-thirds of respondents supported testing high-risk infants for all conditions except T1D (22%). CF was the only condition for which there was majority support for both mandatory NBS (56%) and later population screening (60%). For all other conditions, later population screening was preferred over NBS (P <or= 0.01). Genetic counselors were most likely to test their own child for CF (46%) and least likely to test their own child for T1D (6%). For each condition, genetic counselors were more likely to support NBS if they chose to screen their own newborn (P < 0.001). Attitudes towards NBS were not influenced by year of graduation or professional experience. We can conclude that genetic counselors are supportive of targeted testing of high-risk infants. They prefer voluntary population screening with consent to mandatory NBS for conditions that challenge Wilson and Jungner criteria. Their support for NBS correlates with their interest in testing their own children and not with professional experience.
    American Journal of Medical Genetics Part A 11/2006; 140(21):2312-9. DOI:10.1002/ajmg.a.31485 · 2.05 Impact Factor
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