EPOS

European Paediatric Ophthalmological Society

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AETIOLOGY OF OCULAR COLOBOMA IN SOUTH INDIA

Hornby Stella, Gilbert Clare, Jones Barry, Dandona Lalit
¹Radcliffe Infirmary Oxford UK, ²London School of Hygiene and Tropical Medicine UK, ³Moorfields Eye Hospital London UK, ⁴L.V. Prasad Eye Institute Hyderabad India

Purpose: To identify environmental and genetic factors in the aetiology of congenital colobomatous eye malformations in India. Background: Ocular coloboma and microphthalmos with cyst form a spectrum of developmental abnormalities of the eye caused by failure of fusion of the embryonic fissure. Little is known about the aetiology of these conditions in India where these conditions appear to be more common than in the West. Methods: Children with colobomatous malformations were recruited from schools for the blind, hospital records and community-based rehabilitation programs in India. 83 mothers of affected children were interviewed to obtain information on possible genetic and environmental risk factors in particular consanguinity, sibling risk, birth order, symptoms of vitamin A deficiency, drug use, maternal illness in pregnancy and possible exposure to agricultural chemicals. Results:The parents were consanguineous in 43.4%. The sibling risk was 3.4%. The frequency of coloboma was highest in the second birth order. Eleven (15.7%) of the mothers had a history of night blindness in the pregnancy with the affected child. 2 had taken abortifacient agents.15 mothers (18%) took medications during pregnancy. 3 mothers reported fever in the first trimester. 11 mothers (13.3%) were exposed to agricultural chemicals. Conclusion: Consanguinity and maternal vitamin A deficiency are common among mothers of children with coloboma in this population. A hypothesis that gene-environment interaction between vitamin A deficiency in pregnancy and genetic susceptibility is proposed. The importance of studying gene-environment interactions is that the potential for prevention of congenital malformations through environmental manipulation is much higher than for purely genetic disorders. Reference