Partial trisomy 3p syndrome.

Two cousins with an unbalanced chromosome translocation (partial trisomy 3p) are described. Both children have a clinically recognizable syndrome of square facies with prominent cheeks, narrow bitemporal regions, psychomotor retardation and congenital heart disease. Extended family studies showed one other individual proven to have partial trisomy 3p karyotype, two retarded individuals with congenital heart disease who probably had it, and 14 balanced carriers of the translocation t(1;3)(q43;p21). This report confirms the characteristic clinical appearance of affected individuals and emphasizes the frequency in which congenital heart disease is the presenting feature of partial trisomy 3p. An additional 22 cases of partial 3p trisomy are reviewed.