Consanguinity and chromosomal abnormality.

ABSTRACT

BACKGROUND: Consanguinity is defined as the marriage between close relatives. The deleterious effects associated with consanguinity may be caused by the expression of rare recessive genes inherited from common ancestors. AIMS AND OBJECTIVES: The present study was undertaken to analyze the effect of consanguinity on chromosomal abnormality (CA). METHODS AND MATERIALS During last 6 years period, a total of 1465 cases with suspected genetic etiology like bad obstetric history, mental retardation, multiple congenital anomalies, Down syndrome, primary amenorrhea and primary infertility was referred to Division of Human Genetics for karyotyping and genetic counseling. The information regarding consanguinity was obtained through pedigree analyzes up to three generations from all the patients. Chi-square test was applied to test the significance. RESULTS: Consanguinity was seen in 427 cases (29.14%), 305 cases were confirmed to have CA, among them 240 (78.7%) had numerical abnormality and 65 (21.3%) had structural abnormality. The presence of consanguinity in CA was seen in 53 cases (17%), including 43 (81.1%) with numerical and 10 (18.9%) with structural abnormality. CONCLUSION: The effect of consanguinity on CA was almost significant ( P < 0.001), whereas the effect was not significant for the type of CA. It may be because of the pooled types of consanguinity as well as the CA. Further information is needed to state categorically that there could be the effect of consanguinity on CA.