Automated fluorescent genotyping detects 10% of cryptic subtelomeric rearrangements in idiopathic syndromic mental retardation
- M Rio,
- F Molinari,
- S Heuertz,
- C Ozilou,
- P Gosset,
- O Raoul,
- V Cormier-Daire,
- J Amiel,
- S Lyonnet,
- M Le Merrer,
- C Turleau,
- M-C de Blois,
- M Prieur,
- S Romana,
- M Vekemans,
- A Munnich,
- L Colleaux
- Unité de Recherches sur les Handicaps Génétiques de l'Enfant, INSERM U-393, et Département de Génétique, Hôpital Necker-Enfants Malades, Paris, France
- Correspondence to: Dr L Colleaux, INSERM U393, Hôpital Necker-Enfants Malades, 149 rue de Sévres, 75015 Paris, France; colleaux{at}necker.fr
- Accepted 17 January 2002
- Revised 16 January 2002
Abstract
Recent studies have shown that cryptic unbalanced subtelomeric rearrangements contribute to a significant proportion of idiopathic syndromic mental retardation cases. Using a fluorescent genotyping based strategy, we found a 10% rate of cryptic subtelomeric rearrangements in a large series of 150 probands with severe idiopathic syndromic mental retardation and normal RHG-GTG banded karyotype. Fourteen children were found to carry deletions or duplications of one or more chromosome telomeres and two children had uniparental disomy. This study clearly shows that fluorescent genotyping is a sensitive and cost effective method that not only detects cryptic subtelomeric rearrangements but also provides a unique opportunity to detect uniparental disomies. We suggest giving consideration to systematic examination of subtelomeric regions in the diagnostic work up of patients with unexplained syndromic mental retardation.
- MR, mental retardation
- CGH, comparative genomic hybridisation
- FISH, fluorescence in situ hybridisation
- UPD, uniparental disomy
- PFGE, pulse field gel electrophoresis
- DOP-PCR, degenerate oligonucleotide primed polymerase chain reaction
