Congenital hypomyelinating neuropathy is a rare condition characterized by prenatal, neonatal or early infantile onset of hypotonia, paresis and areflexia. Most of the few patients described in literature die within the first years of life. Histopathologically there are no or thin myelin sheaths. Mutations have been described in the following genes, MPZ, EGR2, PMP22, and MTMR2. Here we describe a family with a heterozygous mutation in MPZ, confirmed in two generations. (C) 2007 Elsevier B.V. All rights reserved.