AUTOSOMAL RECESSIVE PERIPHERAL NEUROPATHY WITH NEUROMYOTONIA (ARAN-NM): DESCRIPTION OF A CLINICAL CASE CONFIRMED BY A MUTATION IN THE HINT1 GENE

Abstract

Autosomal recessive peripheral neuropathy with neuromyotonia (ARAN-NM) is a relatively newly described disease associated with mutations in the HINT1 gene. It accounts for a significant part of the poorly differentiated forms of axonal polyneuropathies. We present the first in Russia description of the genetically confirmed case of ARAN-NM in a boy aged 14 years and 11 months without the hereditary-tainted anamnesis. On presentation, the patient experienced progressive distal muscular weakness, asymmetric foot deformity, gait disorders and minimal manifestations of neuromyotonia (stiffness in the fingers). During examination, we detected an increase in the level of creatine phosphokinase up to 635 U/l, a disturbance of conduction of motor and, to a lesser extent, sensory fibers of the peripheral nerves (according to the stimulation electromyography, EMG), denervation-reinnervation changes, single positive acute waves, fibrillation potentials, complex repeated discharge (according to the data of needle EMG). In the study of exome, a homozygous mutation c.110G>C, p.R37P was determined in exon 01 of the HINT1 gene, which confirmed the presence of ARAN-NM. A molecular-genetic examination of the patient's immediate relatives was carried out. The described case is compared with literature data. An overview of currently available information on ARAN-NM is provided. Diagnostic criteria of the disease are presented.