Developmental delay and growth failure caused by a peroxisomal disorder, dihydroxyacetonephosphate acyltransferase (DHAP-AT) deficiency

We describe a 6 1/2-year-old-girl presenting with a unique phenotype and dihydroxyacetonephosphate acyltransferase (DHAP-AT) deficiency (1.6% of control activity in cultured fibroblasts), a peroxisomal enzyme deficiency which was reported previously to cause rhizomelic chondroplasia punctata (RCDP). Her phenotype is less severe than that seen in classical RCDP, and is notable for short stature, microcataracts, normal limbs, mild hypotonia, and severe mental retardation. Epiphyseal stippling is present. This patient illustrates the variability of peroxisomal disorders whereby a specific defect in peroxisomal plasmalogen synthesis may lead to several phenotypes. Her case also suggests that children presenting with deficient growth, developmental delay, and epiphyseal stippling should be screened carefully for peroxisomal disorders, with measurement of plasmalogens in addition to very long chain fatty acids.