Sensory–Motor Polyneuropathy in an 11-year- old Girl with a Pathogenic Variant in SMC1A: A Case Report

Angelica De Luisa; Carlo A. Cesaroni; Marzia Pollazzon; Carlotta Spagnoli; Stefano G. Caraffi; Alberta Leon; Susanna Rizzi; Daniele Frattini; Anna Cavalli; Livia Garavelli; Carlo Fusco

doi:10.1055/a-2447-1508

Neuropediatrics, Table of Contents

Neuropediatrics 2025; 56(01): 056-060
DOI: 10.1055/a-2447-1508

Short Communication

Sensory–Motor Polyneuropathy in an 11-year- old Girl with a Pathogenic Variant in SMC1A: A Case Report

Authors

Angelica De Luisa

¹Child Neurology and Psychiatry Unit, Pediatric Neurophysiology Laboratory, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Carlo A. Cesaroni

¹Child Neurology and Psychiatry Unit, Pediatric Neurophysiology Laboratory, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Marzia Pollazzon

²Medical Genetics Unit, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Carlotta Spagnoli

¹Child Neurology and Psychiatry Unit, Pediatric Neurophysiology Laboratory, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Stefano G. Caraffi

²Medical Genetics Unit, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Alberta Leon

³R & I Genetics, Italian National Health System, C.So Stati Uniti 4int.F, Padua, Italy
Susanna Rizzi

¹Child Neurology and Psychiatry Unit, Pediatric Neurophysiology Laboratory, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Daniele Frattini

¹Child Neurology and Psychiatry Unit, Pediatric Neurophysiology Laboratory, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Anna Cavalli

¹Child Neurology and Psychiatry Unit, Pediatric Neurophysiology Laboratory, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Livia Garavelli

²Medical Genetics Unit, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
Carlo Fusco

¹Child Neurology and Psychiatry Unit, Pediatric Neurophysiology Laboratory, Mother and Child Department, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy

Abstract

Pathogenic variants in the SMC1A gene are often dominant-negative and cause an X-linked form of Cornelia de Lange syndrome (CdLS) with growth retardation and typical facial features. However, rare SMC1A variants cause a developmental and epileptic encephalopathy (DEE) with intractable early-onset epilepsy that is absent in CdLS. Here we describe an 11-year-old girl with epilepsy, walking disorder, and neurodevelopmental disorder. A neurophysiological examination of nerve conduction velocity showed a mixed, sensory–motor, chronic 4-limb polyneuropathy. Whole-exome sequencing identified the variant c.3145C > T p.(Arg1049*) in SMC1A (NM_006306.3), which can be classified as pathogenic. To the best of our knowledge, among 79 individuals with SMC1A-related DEE reported in the literature, altered peripheral nerve conduction has never been described. In this article, we propose that severe sensory–motor polyneuropathy could be an expansion of the SMC1A-related phenotype.

Keywords

SMC1A - epilepsy - neurodevelopmental disorder - neuropathy

Full Text

References

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