Dentinogenesis imperfecta is a rare,autosomal,dominantly inherited disease of the teeth that occurs in about one in 8000 people Witkop 1957 .The teeth are somewhat brown in color,and the crowns wear down rapidly.Assume that a male with dentinogenesis imperfecta and no family history of the disease marries a woman with normal teeth.What is the probability that their first two children will have dentinogenesis imperfecta? A)1/4 B)100% C)1/2 D)3/4 E)1/8

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The male has the disease and no family history, so he must be heterozygous (Dd). The woman has normal teeth, so she must be homozygous recessive (dd). The probability that their first child will have dentinogenesis imperfecta is 1/2 (Dd). The probability that their second child will have dentinogenesis imperfecta is also 1/2 (Dd). The probability that both children will have dentinogenesis imperfecta is (1/2) x (1/2) = 1/4.

Dentinogenesis Imperfecta is a Rare,autosomal,dominantly Inherited Disease of the Teeth