Pena-Shokeir phenotype in sibs with macrocephaly but without growth retardation.

A number of more or less distinct subgroups with the Pena-Shokeir phenotype have been identified. We studied two brothers with the Pena-Shokeir phenotype who were unusual because they had macrocephaly and normal growth. In the second sib, no neuromuscular abnormalities were found at autopsy. Among the subgroups with Pena-Shokeir phenotype, these sibs resemble the family reported by Ohlsson et al. [1988] more than the other subgroups that have been proposed. In addition, abnormalities were detected by prenatal ultrasonography during the 18th week of gestation of the second fetus. This finding provides additional evidence that this phenotype may be detected early enough in gestation to consider intervention.