Consanguinity, non-disjunction, parental age and Down's syndrome.
The effect of consanguinity on the non-disjunction mechanism in Down's syndrome, was examined in 417 cytogenetically confirmed Down's syndrome patients. The incidence of parental and grandparental consanguinity was 17.5% (n = 73), while that of only parental consanguinity was 17.2% (n = 71). First cousin marriages occurred more frequently, than uncle-niece and 2nd cousin marriages. With regard to parental age, only the mean age difference between consanguineous couples significantly differed from non-consanguineous couples. The inbreeding coefficient did not differ between trisomy 21 and translocation Down's families. From this study, it is concluded that consanguinity does not predispose to Down's syndrome.
Sayee
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Department of Anatomy, St John's Medical College, Bangalore.
Thomas
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IM
D000328:Adult; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003241:Consanguinity; D004314:Down Syndrome / Q000453:epidemiology* / Q000235:genetics*; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010290:Parents; D012307:Risk Factors; D012494:Sampling Studies; D017678:Sex Distribution; D018709:Statistics, Nonparametric