Cleft lip is a common birth defect. Its incidence in the general population is about 0.001, but relatives of affected children are at higher risk Relatives of affected Risk(relative to degree affected child general population Sibs X40 Children 3.5 X35 Aunts and uncles 2nd 0.7 Nephews and nieces 2nd 0.8 First cousins 3rd 0.3 x8 Are these findings consistent with autosomal dominant inheritance of cleft lip? No, because the percentages of 1st and 2nd degree relatives who are affected are too low(would expect 50% and 25%, respectively) Are these findings consistent with autosomal recessive inheritance of cleft lip? lo, because the percentage of affected siblings is too low(would expect 25%)and because the risk in children is nearly as high as that in siblingsCleft lip is a common birth defect. First cousins Nephews and nieces Aunts and uncles Children Sibs Risk (relative to general population) degree % affected Relatives of affected child 1st 4.1 x40 1st 3.5 x35 2nd 0.7 x7 2nd 0.8 x8 3rd 0.3 x3 Are these findings consistent with autosomal dominant inheritance of cleft lip? No, because the percentages of 1st and 2nd degree relatives who are affected are too low (would expect 50% and 25%, respectively). Are these findings consistent with autosomal recessive inheritance of cleft lip? No, because the percentage of affected siblings is too low (would expect 25%) and because the risk in children is nearly as high as that in siblings. about 0.001, incidence in the general population is but relatives of affected children are at higher risk: Its