Fragile X syndrome with FMR1 and FMR2 deletion

Citation
Sj. Moore et al., Fragile X syndrome with FMR1 and FMR2 deletion, J MED GENET, 36(7), 1999, pp. 565-566
Citations number
6
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Molecular Biology & Genetics
Journal title
JOURNAL OF MEDICAL GENETICS
ISSN journal
00222593 → ACNP
Volume
36
Issue
7
Year of publication
1999
Pages
565 - 566
Database
ISI
SICI code
0022-2593(199907)36:7<565:FXSWFA>2.0.ZU;2-5
Abstract
We report a 13 year old boy with fragile X syndrome resulting from a de nov o deletion of the FMR1 and FMR2 genes extending from (and including) DXS753 6 proximally to FMR2 distally. The patient has severe developmental delay, epilepsy, and behavioural difficulties, including autistic features. He has epicanthic folds, in addition to facial features typical of fragile X synd rome, and marked joint hypermobility. We compare our patient to the three o ther cases reported in which both FMR1 and FMR2 are deleted. This case has the smallest deletion reported to date. All four patients have epilepsy and a more severe degree of mental retardation than is usual in fragile X synd rome resulting from FMR1 triplet repeat expansion. Three of the patients ha ve joint laxity and two have epicanthic folds. We suggest that these featur es, in particular severe developmental delay and epilepsy, may form part of the characteristic phenotype resulting from deletion of both FMR1 and FMR2 genes. The diagnosis in this case was delayed because routine cytogenetics showed no abnormality and standard molecular tests for FMR1 triplet repeat expansion (PCR and Southern blotting) failed. Further DNA studies should b e undertaken to investigate for a deletion where clinical suspicion of frag ile X syndrome is strong and routine laboratory tests fail.