Ugwu Rosemary Ogochukwu and Eneh Augusta Unnoma
There is some evidence to suggest that the process of twinning may be associated with higher risk of congenital abnormality. In the process of twinning, developmental disruptions occur which may cause susceptibility to environmental agents. Concordance however is rare. We report cases of 5 sets of twins concordant for the same congenital defect. Zygosity was determined by the gender, blood group and placentation. The first set of twins was dizygous males with neural tube defect. The second set of twins was both females of unknown zygosity with bilateral cleft lip and palate. The third set of twins was monozygous males with features suggestive of trisomy 21 (Down syndrome). The fourth set of twins were dizygous twins with hypospadias, while the fifth set of twins were conjoined twins with huge omphalocoele (thoraco-omphalopagus), a single heart and liver. Because of the multifactorial inheritance pattern of many congenital abnormalities, twins are usually discordant. The rarity of concordance of congenital abnormalities makes their presence in these cases interesting. The likelihood of it being concordant is higher if they are monozygous or same sex dizygous
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