We report on a pair of monozygotic twins with Fryns syndrome discordant for
severity of diaphragmatic defect, Both twins had macrocephaly, "coarse" fa
cial appearance, hypoplasia of distal phalanges, and an extra pair of ribs.
Twin A lacked an apparent diaphragmatic defect, and at 1 year of age had m
ild developmental delay. Twin B had a left congenital diaphragmatic hernia
and died neonatally. Absence of diaphragmatic defect in Fryns syndrome may
represent a subpopulation of more mildly affected patients whose developmen
tal outcome is currently undetermined. (C) 2000 Wiley-Liss, Inc.