Whether Paternal Age Effect Exists as a Risk Factor in Trisomy 21

Minakshi Vashist¹, Neelkamal²* and Amit Kumar³

Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana India.

ABSTRACT: Background Down syndrome (Trisomy -21) is a most common aneuploid condition caused by the presence of an extra 21 chromosome and is a major cause of mental retardation. The only etiological factor that has been established in literature is advanced maternal age for the occurrence of trisomy 21 but little is known about the genetic consequences of advanced paternal age. The study was carried out to find the effect of paternal age on trisomy-21. Methodology Present study has been conducted on 200 cases of Down syndrome from 30 centers of 12 districts of Haryana. These patients were subjected to detailed morphogenetic & cytogenetic analysis. Results & conclusion Variability in age of father was found at the birth of mongoloid child. It varied from 19 years to the 48 years. Most of the Down syndrome cases (63) were born from the father of age between 31-35 years. Correlation between father’s age and number of Down syndrome cases (keeping mother age constant) came out as r = 0.041. Partial correlation coefficient showed that increase risk of Down syndrome may be due to combined effect of advanced parental age. Down syndrome cases born to father of less than 30 years of age were 40.5% while those born to more than 30 years of age were 59.5%. The existence of a paternal age effect on Down syndrome is controversial but an important factor & it should not be ignored in morphological & cytogenetic analysis of patients.

KEYWORDS: Down syndrome; human genetics; nondisjunction; Paternal age; Trisomy 21

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