Diagnostic definition of the FG syndrome

The need for improving the delineation of the FG phenotype, which at present probably is biased toward the more severe end of the clinical spectrum prompts us to offer information concerning two additional cases. Our two patients had only minimal manifestations of the anal and/or gastrointestinal defects seen to date in 3/4 FG syndrome patients. Neither did they have the severe constipation that occurs in over half. Also, they had microcephaly, which as been seen in only a few FG patients (who usually have megalencephaly). The most consistent visceral involvement was heart defect, previously observed in three FG males. The other manifestations, including severe MR, characteristic personality, hypotonia, developmental dealy, and distinctive facial appearance with minor anomalies of auricles, fit the diagnostic criteria of the FG syndrome. This condition probably is underdiagnosed, because a clear working definition of the syndrome is not yet available. In agreement with Opitz et al [1982] we suggest that the FG syndrome should be suspected in all retarded and hypotonic males in whom characteristic facial appearance, personality and minor physical anomalies are present, even in the absence of major visceral anomalies.