High rate of detection of subtelomeric aberration by using combined MLPA and subtelomeric FISH approach in patients with moderate to severe mental retardation.
OBJECTIVE
(1) To evaluate the prevalence of subtelomeric deletion in moderate to severe mental retardation population, (2) to assess the feasibility and cost-effectiveness of combined methodology in routine workup of this sub-population.


METHODS
Twenty unrelated patients using strict selection criteria were recruited for the study from the Clinical Genetic Service. Patients were initially screened by Multiplex Ligation-dependent Probe Amplification (MLPA) for subtelomeric imbalance followed by FISH analysis for anatomical integrity. This is then followed by parental subtelomeric FISH analysis.


RESULTS
Three subtelomeric deletions were identified. They were Deletion 1p36, Deletion 1q44 and Deletion 10q26; these were previously unidentified by conventional technique.


CONCLUSIONS
The prevalence of subtelomeric deletion in our cohort of moderate to severe mental retardation patients is consistent with published findings of around 10%. The figure is on the higher side if more stringent criteria is used. The combination of strict clinical criteria, MLPA and selective subtelomeric FISH was shown to be feasible and cost-effective.
Clinical Genetic Service, Department of Health, HKSAR Government, Cheung Sha Wan, Kowloon, Hong Kong. albert@sinacampus.com
Albert C F
AC
Lam
Stephen T S
ST
Lam
Kent K S
KK
Lai
Tony M F
TM
Tong
T C
TC
Chau
D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D005260:Female; D020440:Gene Duplication; D006579:Heterozygote; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D015336:Molecular Probe Techniques; D018579:Patient Selection; D010375:Pedigree; D010865:Pilot Projects; D016615:Telomere / Q000235:genetics*