Several previous papers have reported families with patients manifesting later onset phenotype in conjunction with either adolescent or adult onset phenotypes.22, 30, 34, 35, 36, 37 However, only three families have been reported previously to involve both early and later onset forms.30 The fact that different phenotypes are observed in related patients suggests that factors other than the GALC mutations alone influence the clinical course of Krabbe's disease, which makes prognosis prediction difficult. The gene discussed is GALC; the disease is Krabbe disease.