Early clinical symptoms were analyzed from all known 43 children with aspartylglucosaminuria, born during 1974-1989 in Finland. Pre- and perinatal histories appeared normal for all children, except for muscular hypotonia and weak sucking in some babies. Three infants had abduction stiffness in the hips, needing follow-up. Other abnormalities found in infancy were umbilical or inguinal hernias and unusual susceptibility to respiratory and ear infections. This susceptibility diminished clearly in most patients after six years of age. Episodic diarrhea, described earlier, appeared to be a rather infrequent symptom and a less valuable diagnostic clue. New clinical phenomena were talipes planovalgus or clubfoot, needing surgical treatment, and aggressive behavior, needing, occasionally, child psychiatric consultation or treatment. In addition, angiokeratoma of the skin, not an infrequent phenomenon among adult patients, was found in one child. The main indications for further studies were delayed speech, attention deficit and clumsy or delayed motor functions. The disease is easily misdiagnosed and, universally, probably underdiagnosed. Its incidence in Finland was recalculated and appeared to be at least 1 in 18,500 live-born babies in this country.