Fragile X mutation and FG syndrome-like phenotype

✍ Scribed by Piussan, Ch.; Mathieu, M.; Berquin, P.; Fryns, J. P.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 454 KB
• Volume: 64
• Category: Article
• ISSN: 0148-7299
• DOI: 10.1002/(sici)1096-8628(19960809)64:2<395::aid-ajmg32>3.0.co;2-8

✦ Synopsis

We present data on 4 mentally retarded brothers, 2 of whom were dizygotic twins withcongenital hypotonia, constipation, head size disproportionately large for length or height, and a combination of minor anomalies suggestive of FG syndrome. These brothers have a mentally retarded full sister with similar minor anomalies and an older half-brother with the Martin-Bell syndrome.

The mother is mentally retarded; 4 of 7 individuals are positive for fragile X, but all have a CGG expansion ranging from 0.2-2 to 4 kb. Although the phenotype is not completely typical of the FG syndrome and the coincidence of the FMRl mutation and segregation of the MCA/MR phenotype are highly unlikely, the FMRl mutation may affect morphogenesis more extensively and differently than the Martin-Bell syndrome does to effect an FG syndromelike phenotype in certain families. This phenotype does not appear to be a contiguous gene syndrome, but an effect of the FMRl mutation on an adjacent gene must be considered.