| Dred_ID | RD00035 |
| OMIM ID | 300624 |
| Disease name | Fragile X Mental Retardation Syndrome |
| Alternative names | Fragile X Syndrome
Mental Retardation, X-linked, Associated with Marxq28
X-linked Mental Retardation and Macroorchidism
Marker X Syndrome
Martin-bell Syndrome
|
| Category | Genetic diseases, Rare diseases, Neuronal diseases, Eye diseases, Reproductive diseases, Endocrine diseases, Fetal diseases, Mental diseases |
| Phenotype | NIH Rare Diseases: Fragile X syndrome is a genetic condition involving changes in part of the X chromosome. This condition causes a range of developmental problems including learning disabilities and cognitive impairment. It is the most common form of inheritedintellectual disability in males and a significant cause of intellectual disability in females. Other signs and symptoms may include symptoms of autism spectrum disorders, seizures, and characteristic physical features. Fragile X syndrome is caused by a change (mutation) in the FMR1 gene and is inherited in an X-linked dominant manner. There is no cure yet and treatment is based on the symptoms present in the person. Early physical and education therapy is recommended.
OMIM: Fragile X syndrome is characterized by moderate to severe mental retardation, macroorchidism, and distinct facial features, including long face, large ears, and prominent jaw. In most cases, the disorder is caused by the unstable expansion of a CGG repeat in the FMR1 gene and abnormal methylation, which results in suppression of FMR1 transcription and decreased protein levels in the brain (Devys et al., 1993). |
| Miscellaneouse | OMIM:
incomplete penetrance
50% of females have learning disability or mild mental retardation
prevalence approximately 1 in 4,000 males
most cases (98%) caused by expanded trinucleotide repeat (cgg)n in the fmr1 gene
repeat is unstable if > 52 repeats
symptomatic if > 200 repeats
some boys with premutations (55 to 200 repeats) may show milder features, including autistic features |
| Prevalence | Prevalence: 1-5/10000 (Worldwide),1-5/10000 (Europe),1-9/100000 (United States),1-9/100000 (France),1-5/10000 (Spain),1-5/10000 (Canada) [source: MalaCards] |
| Inheritance | X-linked dominant |
| Anticipation | Yes |
| Evidence | Strong |