Profile of chromosomal abnormalities in the Al Jahra region of Kuwait

Objective: One hundred and seventy-seven newborn babies with chromosomal abnormalities were studied at the Al-Jahra satellite clinic of the Kuwait Medical Genetics Centre (KMGC), Kuwait, over a 7-year period from January 1983 to December 1989 to make a reanalysis and recomputation of the statistical results of the previous short-term stud ies. Methods: The data were collected from the registry of chromosomal abnormalities and from the clinical records of the patients in KMGC retrospectively. Controls were selected from the newborn babies delivered in the same period of study. The logistic regression analysis was computed using dependent/independent variables. Results: Ninety-five percent of the cases had numerical chromosomal abnormalities, and 5% had structural chromosomal abnormalities. One hundred and forty-five cases had classic trisomy 21, with an incidence of 2.9/1,000 live births (LB), 16 cases had trisomy 18 (0.3/1,000 LB), 5 cases had trisomy 13 (0.1/1,000 LB), 1 case had triploidy 69,XXY (0.02/1,000 LB) and 1 had Turner's syndrome (0.05/1,000 female LB). Nine cases with structural chromosomal abnormalities were enumerated, dir dup(1) (p21-p32), del(l)(q32-q42), del(13)(q22-q34) and inversion Y chromosome, the incidence was 0.02/1,000 LB for each. Two cases of translocation trisomy 21 (0.04/1,000 LB) and 3 cases of cri-du-chat (0.06/1,000 LB) were enumerated too. Bedouins had a double-fold increased risk of trisomy 21 (odds ratio = 1.819, p = 0.032), and advanced maternal age was also a risk factor while paternal age showed inconsistent pattern of risk. Conclusion: This study confirmed the high incidence of the common trisomies and the role of advanced maternal age and the Bedouin ethnicity as a risk factor.