Congenital hypomyelinating neuropathy: Two patients with long-term follow-up

The authors report the long-term prospective follow-up of two unrelated fem ales with congenital hypomyelinating neuropathy (CHN) and review previously reported cases. The authors' first patient presented with neonatal hypoton ia and extremely slow nerve conduction velocities. Sural nerve biopsy revea led profound hypomyelination, without inflammation or evidence of myelin br eakdown, She is now 9 years of age, and her motor function has continued to improve, Follow-up nerve-conduction velocities are unchanged. The authors' second patient presented at 5 months with hypotonia, Nerve-conduction velo cities were extremely slow, and sural nerve biopsy revealed severe hypomyel ination, with no inflammation or evidence of myelin breakdown. She is now 5 years of age and has also demonstrated improved motor function, Repeated n erve-conduction velocities are unchanged, Both patients have normal cogniti ve development. Molecular genetic analysis in Patient 2 disclosed a point m utation in the myelin protein zero gene; this same point mutation has been reported in three other patients diagnosed with Dejerine-Sottas syndrome (D SS) but has never been reported in a patient with CHN. Although CHN is a di stinct clinical entity, it may share similar genetic features with DSS, (C) 1999 by Elsevier Science Inc. All rights reserved.