The disease is most severe in affected males. In the classic form (where the enzyme activity is absent) the clinical findings are represented by pain and paresthesias in the extremities, vessel ectasia (called angiokeratoma) in skin and mucous membranes, and hypohidrosis (a reduced sweating) during childhood or adolescence. Corneal and lenticular opacities may be present. Proteinuria, renal impairment,cardiac and neurological lesions develop with time, together with hypertension. When end stage renal disease occurs, dialysis or renal transplantation may be necessary. In heterozygous females a residual enzymatic activity may be demonstrated and they usually have asymptomatic or later onset disease manifestations, although rarely they could develop a disease as severe as in males.