Hereditary Motosensory Neuropathy Type I (Charcot–marie–tooth Disease, Type I A): A Clinical Case of an Early Onset of the Disease

Abstract

Hereditary motor sensory neuropathies (HMSNs) are the most common degenerative disorders of the peripheral nervous system in children. In this pathology, degenerative lesions of the myelin sheaths and/or axons lead predominantly to distal paralytic amyotrophy, affecting mainly the lower extremities, and are accompanied by areflexia. A clinical case of HMSN type I (Charcot–Marie–Tooth disease, type I A) with an early (up to 1 year) onset of the disease is described. The clinical features of this observation are a very early onset of the disease with a debut before the age of 1 year, the absence of pronounced amyotrophies and characteristic deformities of the feet («hollow foot»). To diagnose this genetic disease, a molecular genetic study was carried out. As a result of DNA sequencing (panel «Neuromuscular diseases»), data were obtained on the presence of a duplication of a segment of chromosome 17 with approximate boundaries of 14005424 – 15162520 bp, covering sections of several genes, including the PMP22 gene. Chromosomal micromatrix targeted analysis revealed a microduplication of the short arm (p) region of chromosome 17 from position 14076430 to position 15441811, covering the 17p12 region. The duplication zone also includes the PMP22 gene, the duplication of which is the cause of Charcot–Marie–Tooth disease, type 1A. At this time, there are no methods of pathogenetic therapy for HMSN, therefore, early diagnosis is of great practical importance, which makes it possible to start rehabilitation measures and prevent the disease in burdened families in a timely manner, based on medical genetic counseling and prenatal DNA diagnostics.