We report a case of hereditary sensory and autonomic neuropathy presenting with childhood-onset symmetric distally predominant limb hypoesthesia to tactile, thermal, and painful stimuli. Exome sequencing identified a homozygous pathogenic variant in the with-no-lysine (K) kinase 1 (WNK1), lysine deficient protein kinase 1 gene. The clinical, electrophysiological, and genetic findings confirmed a diagnosis of hereditary sensory and autonomic neuropathy type 2A (HSAN 2A). This case highlights the importance of genetic confirmation in the evaluation of early-onset neuropathies, especially when the most common causes have been ruled out. Significantly, our observations underscore the potential role of skin biopsy in identifying autonomic abnormalities in HSAN 2, possibly contributing to a better understanding of these rare neuropathies. We also reviewed the reported cases of this disease in the literature to highlight its phenotypic variability.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with a complex genetic architecture, showing monogenic, oligogenic, and polygenic inheritance. In this study, we describe the case of a 71 years-old man diagnosed with ALS with an atypical phenotype, due to the presence of a progressive ocular ptosis. Genetic analyses revealed two variants in SOD1 and TBK1 genes respectively and the LHON-associated m.14484T>C variant in the mitochondrial DNA (mtDNA). We discuss how all these variants may synergically impinge on mitochondrial function, contributing to the pathogenic mechanisms which might ultimately lead to the neurodegenerative process, possibly influencing the clinical ALS phenotype.

We present a family of five siblings who came to our attention with a clinical and radiological diagnosis of familial hypomyelinating leukodystrophy. Despite brain white matter abnormalities being present in all siblings, the clinical phenotype was variable: the three brothers presented with a clear-cut late-onset spastic paraplegia, whereas the two sisters displayed only mild pyramidal signs. Molecular analysis revealed a single relevant variant shared by all affected siblings, namely the likely pathogenic variant c.659C>T (p.Ser220Phe) in the GJA1 gene. Variants in this gene are generally associated with oculodentodigital dysplasia (ODDD), an autosomal dominant condition characterized by distinctive facial features and anomalies of the eyes, teeth, and digits. Neurological features are reported in about 30% of cases. In this family, ODDD manifested as a predominantly neurological phenotype. Although a clear explanation for this uncommon presentation is lacking, shared genetic modifiers, the effect of the specific variant, and a possible patient-population bias may have contributed. This case highlights the wide phenotypic spectrum of CX43-related disorders and suggests the importance of testing the GJA1 gene in individuals with atypical presentations, including predominant or isolated neurological phenotypes such as late-onset spastic paraplegia. MRI findings may also provide a useful diagnostic clue when ODDD is suspected.