Effect of second-hand smoke exposure on TGFa gene polymorphism at the K primer region among non-syndromic oral cleft patients

Objective: To determine the association between maternal exposure to second-hand smoke during pregnancy and TGFα gene polymorphism in the cleft children genotype. Material and Method: Retrospective cohort study was carried out among cleft children with and without maternal exposure to cigarette smoke during pregnancy. The cleft children were selected from the Combined Cleft Clinic at Kota Bharu Dental Clinic. A total of 33 subjects were identified as exposed (16 Males and 17 Females) and 32 were identified as non-exposed (20 Males: 12 Females) with age range from 3 months to 10 years. The subjects' mothers (age range from 17 to 50 years old) were interviewed using the standard craniofacial deformity registration form used at the Combined Cleft Clinic. Blood samples were taken from the subjects. DNA was extracted and amplified with PCR. Then the Restriction Fragment Length Polymorphism (RFLP) technique was used with enzyme Hinf1 and Nco1 to detect polymorphism at the K primer region of the TGFα gene. Results: The chi-square(X 2 ) test detected a significant difference of allele 4 at K region between exposed and non-exposed subjects (95% CI: 1.07, 8.06); p=0.034. Simple logistic regression analysis revealed that maternal exposure to second-hand smoke for more than 30 minutes per day had the relative risk of 3.82 times of having allele 4 polymorphism among exposed compared to non-exposed subjects (95% CI: 1.29, 11.28) p=0.015. Conclusion: Maternal exposure to second-hand smoke during pregnancy was significantly associated with polymorphism of allele 4 at K-primer region of TGFα gene in sporadic non- syndromic oral cleft patients.