Unknown syndrome: Hirschsprung's disease,

microcephaly, and iris coloboma: a new syndrome of defective neuronal migration SUMMARY We describe three children with Hirschsprung's disease and microcephaly, two of whom also have an iris coloboma. Two of the children, one with a coloboma and one without, are from the same consanguineous pedigree. The third case is unrelated and was identified by the matching program of the London Dysmorphology Data-base. ' This is the first report of this combination of features which are considered to be secondary to defective neuronal migration. An autosomal recessive mode of inheritance is proposed. Case reports CASE 1 This male child was born to a consanguineous couple originally from Pakistan. The pedigree is shown in fig 1. The other affected member is case 2 in this report. Case I was the first child of the parents and was born by normal delivery at 39 weeks ' gestation. Labour was induced because the ultrasound scan suggested intrauterine growth retardation. At birth, his weight was 2-25 kg (3rd centile) but his head circumference at 30 cm was 3 cm less than th