Sujet(s)
Délétion de segment de chromosome , Chromosomes humains de la paire 15/génétique , Syndrome de Prader-Willi/génétique , Études d'associations génétiques , Dépistage génétique , Génome humain , Hong Kong/épidémiologie , Humains , Syndrome de Prader-Willi/épidémiologie , Syndrome de Prader-Willi/anatomopathologie , Études rétrospectivesRÉSUMÉ
We present the first confirmed case by molecular analysis of a metaphyseal chondrodysplasia, McKusick type, in a 22-week fetus. Two novel compound heterozygous mutations, 64T> A and 79G > T, were found in the highly conserved regions of the RMRP gene. Twenty-two heterozygous g.1018 T> C mutations, two homozygous g.1018 T> C mutations, two heterozygous insertion mutations g.799_g.800insC and one heterozygous insertion mutation g.849_g.850insT were found among 100 normal controls. Careful radiological examination of the fetus for skeletal dysplasia allowed definitive diagnosis, proper genetic counselling and future prenatal diagnosis.
Sujet(s)
Endoribonucleases/génétique , Ostéochondrodysplasies/génétique , Avortement eugénique , Adulte , Femelle , Hétérozygote , Humains , Mutation , Grossesse , Analyse de séquence d'ADNRÉSUMÉ
OBJECTIVES: (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. METHOD: 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.
