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Background: Biallelic loss‐of‐function NDUFA12 variants have hitherto been linked to mitochondrial complex I deficiency presenting with heterogeneous clinical and radiological features in nine cases only. Objectives: To fully characterize, both phenotypically and genotypically, NDUFA12‐related mitochondrial disease. Methods: We collected data from cases identified by screening genetic databases of several laboratories worldwide and systematically reviewed the literature. Results: Nine unreported NDUFA12 cases from six pedigrees were identified, with presentation ranging from movement disorder phenotypes (dystonia and/or spasticity) to isolated optic atrophy. MRI showed basal ganglia abnormalities (n = 6), optic atrophy (n = 2), or was unremarkable (n = 1). All carried homozygous truncating NDUFA12 variants, three of which are novel. Conclusions: Our case series expands phenotype–genotype correlations in NDUFA12‐associated mitochondrial disease, providing evidence of intra‐ and inter‐familial clinical heterogeneity for the same variant. It confirms NDUFA12 variants should be included in the diagnostic workup of Leigh/Leigh‐like syndromes – particularly with dystonia – as well as isolated optic atrophy. [ABSTRACT FROM AUTHOR]

Background: Ataxia telangiectasia is one of the most common causes of autosomal recessive cerebellar ataxias. However, absence of telangiectasia, normal levels of alpha‐fetoprotein and negative genetic test may direct to alternative diagnosis with similar phenotypes such as ataxia telangiectasia‐like disorders (ATLD). Cases: We report two instructive cases of ATLD: the first case with ataxia telangiectasia‐like disorder type 1 related to MRE11A gene, and the second case with ataxia telangiectasia‐like disorder type 2 related to PCNA gene. Literature Review: ATLD is an unusual group of autosomal recessive diseases that share some clinical features and pathophysiological mechanisms with ataxia telangiectasia (AT). ATLD may be associated with mutations in the MRE11A (ATLD type 1) and PCNA (ATLD type 2) genes. ATLD belongs to the group of chromosomal instability syndromes. The reason for the term ATLD is related to the similar pathophysiological mechanisms observed in AT, which is characterized by chromosomal instability and radiosensitivity. Conclusions: In this review, the main clinical features, biomarkers, brain imaging and genetics of ATLD are discussed. Mutations in the MRE11A and PCNA genes should be included in the differential diagnosis for early onset cerebellar ataxia with absence of telangiectasia and normal levels of alpha‐fetoprotein. View Supplementary Video 1 [ABSTRACT FROM AUTHOR]

The article discusses a case of hereditary truncal dystonia associated with an ANO3 gene variant. The patient, a 67-year-old woman, presented with flexion of the thoracolumbar spine and a family history of late-onset camptocormia. Genetic testing revealed a likely pathogenic variant in the ANO3 gene, broadening the phenotypic spectrum of ANO3-related dystonias. The study highlights the importance of genetic testing for patients with truncal dystonia and a positive family history, offering insights into the genetic basis of movement disorders. [Extracted from the article]