Most common cause of inherited intellectual disability (ID)
Caused by mutations in the FMR1 gene on chromosome Xq27.3
Affects ~1 in 4,000 to 6,000 males; prevalence in fema...
Birth/neonatal history
Normal to increased birth weight
May have large head circumference at birth
Feeding problems and frequent emesis due to gastroesophageal reflux may occur but impro...
Treatment is aimed at supportive measures.
Per American Academy of Pediatrics (AAP) guidelines, routine evaluation for ocular, ENT, skeletal, and neurologic abnormalities. Ref...
Regular follow-up with a behavioral and developmental pediatrician as well as a psychiatrist/psychologist is recommended for patients with behav...
American Academy of Pediatrics. Health supervision for children with fragile X syndrome. Pediatrics. 2011;127(5):994–1006. [View Abstract on OvidInsights]
Ligsay A, Hagerman RJ...
Q: Why is it called “fragile X syndrome”?
A: Early cytogenetic studies of male patients with ID identified a site on the X chromosome that would appear constricted when the patient’s cells were gro...
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Fragile X chromosome.
FIGURE 4.8. <bold>A:</bold> Fragile X syndrome in a 2.5-year-old boy. Note the long hypotonic face, high forehead, epicanthal folds, and prominent ears. <bold>B:</bold> Five-year-old fragile X–positive girl, referred because of behavior problems. Note the prominent ears.
FIGURE 4.8. <bold>A:</bold> Fragile X syndrome in a 2.5-year-old boy. Note the long hypotonic face, high forehead, epicanthal ...
FIGURE 4.9. Pedigree and polymerase chain reaction blot of fragile X family. <bold>Lane 1:</bold> Male individual with premutation (phenotypically normal transmitting male individual). The polymerase chain reaction blot shows only one band with a slightly greater molecular weight than normal. <bold>Lanes 2 and 7:</bold> Healthy female individuals. On polymerase chain reaction a single band occurs, with approximately 234 base pairs. <bold>Lanes 3 and 5:</bold> Female individuals with premutation. Their polyme...
FIGURE 4.9. Pedigree and polymerase chain reaction blot of fragile X family. <bold>Lane 1:</bold> Male individual with premuta...
FIGURE 4.10. X-linked mental retardation associated with the fragile X chromosome. <bold>A:</bold> Representative Giemsa (GTG) banded karyotype of a 12-year-old boy with mental retardation with relative macrocephaly, prominent brows, deep-set eyes, large ears, and megalotestes. The fragile site (<italic>arrow</bold>) was demonstrated in 28% of cells cultured in folic acid–deficient media. <bold>B:</bold> Fragile X chromosomes from the same patient. Each pair represents the single X chromosome from a cell that ...
FIGURE 4.10. X-linked mental retardation associated with the fragile X chromosome. <bold>A:</bold> Representative Giemsa (GTG)...
FIGURE 30.26. Fluorescence in situ hybridization in A employed a chromosome 5 painting probe on a cell from a patient with severe mental retardation and self-abusive behavior. On G-banded analysis, an abnormal dark staining band was seen in the p arm of chromosome 1. Using a 24-chromosome painting probe device (Cytocell, Ltd., Oxfordshire, UK), the abnormal segment was identified to be derived from chromosome 5 and confirmed using another chromosome 5 painting probe (Vysis, Inc, Downer's Gr...
FIGURE 30.26. Fluorescence in situ hybridization in A employed a chromosome 5 painting probe on a cell from a patient with severe mental re...