A novel homozygous FBXO38 variant causes an early-onset distal hereditary motor neuronopathy type IID

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Distal hereditary motor neuronopathies (dHMN) are a genetically heterogeneous group of neuromuscular disorders caused by anterior horn cell degeneration and progressive distal muscle weakness. A heterozygous missense variant in FBXO38 has been previously described in two families affected by autosomal-dominant dHMN. In this paper, we describe a homozygous missense variant in FBXO38 (c.1577G>A; p.(Arg526Gln)) in a young Turkish female, offspring of consanguineous parents, with a congenital mild neuronopathy with idiopathic toe walking, normal sensory examination, and hearing loss. This work is the first to describe a novel homozygous variant and a suggested loss of function mechanism in FBXO38, expanding the dHMN type IID phenotype.

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We thank all family members for their participation in the study. Suna and Inan Kıraç Foundation is whole-heartedly acknowledged for the generous funding of the study and Koç University Translational Research Center for their support and the inspiring academic environment supplied. We thank Aslı Gündoğdu and Irmak Şahbaz for excellent technical assistance.

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Correspondence to A. Nazlı Başak.

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This work was approved by The Ethics Committee of Boğaziçi University, where the study was started.

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The authors declare that they have no conflict of interest.

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