HMSNL in a 13-year-old Bulgarian girl.

We present a 13-year-old Bulgarian girl with a new form of demyelinating neuropathy with hearing loss. The clinical and neuropathological features of the patient were similar to those of the recently described hereditary motor and sensory neuropathy type Lom (HMSNL), first identified in a large Bulgarian Gypsy population. Neuropathological examination of a peripheral nerve biopsy revealed an excess of nerve fibres with inappropriately thin myelin sheaths compared with the axon diameter, surrounded by concentric Schwann cells without typical onion-bulb formation. The parents of our patient are unaware of Gypsy ancestry and are not in a consanguineous marriage. Genetic analyses showed that the patient was homozygous for the predominant HMSNL haplotype on 8q24. Our findings indicate that HMSNL should be considered in the differential diagnosis of any patient presenting with the symptoms of demyelinating neuropathy with hearing loss, even if no Gypsy ethnic background is reported.