Study on subtelomeric aberrations in children with mental retardation

Abstract

Objective To make an etiology study on children with unexplained mental retardation (MR) by using combined multiplex ligation-dependent probe amplification (MLPA), and to explore associations between subtelomeric aberrations and phenotypes in local children. Methods Sixty-seven children with unexplained MR were enrolled in study group from Jul.2009 to Dec.2011 in Guangdong Women and Children's Hospital.Peripheral blood of patients and their parents were collected as samples of subtelomeric test by MLPA.Two kinds of probes of MLPA were combined to verify the aberration results.After confirmed test the parent of positive children were tested by the same way, then to analyze associations between test data and the clinical feature. Results Among sixty-seven children enrolled in the study aged 6 months to 15 years, where were 42 male and 25 female; the intelligence of 47 children belonged to mild degree(IQ≥50 scores), that of 20 children belonged to severe degree(IQ 0.05). The aberration rate in moderate to severe degree group was higher than those mild degree group.The rates of features including physical developmental retardation, malformation and organ aberrations in positive children were higher than those of the negative cases.There were significant differences between the 2 severity groups (all P<0.05). Conclusions Aberrations in subtelomeric region can be one of the important causes of unexplained MR.The MR patients were supposed to have subtelomeric region tested so as to provide the evidence for diagnosis and genetic counseling. Key words: Mental retardation; Subtelomeric region; Multiplex ligation-dependent probe amplification; Child