Background 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 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 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 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.

BACKGROUND Ataxia with oculomotor apraxia (AOA) is characterized by early‐onset cerebellar ataxia associated with oculomotor apraxia. AOA1, AOA2, AOA3, and AOA4 subtypes may present pathogenic variants in APTX, SETX, PIK3R5, and PNKP genes, respectively. Mutations in XRCC1 have been found to cause autosomal recessive spinocerebellar ataxia‐26 (SCAR26) now considered AOA5. OBJECTIVES To examine a cohort of Brazilians with autosomal recessive cerebellar ataxia plus oculomotor apraxia and determine the frequencies of AOA subtypes through genetic investigation. METHODS We evaluated clinical, biomarkers, electrophysiological, and radiological findings of 52 patients with AOA phenotype and performed a genetic panel including APTX, SETX, PIK3R5, PNKP, and XRCC1. RESULTS We found pathogenic variants in SETX (15 patients), PNKP (12), and APTX (5). No mutations in PIK3R5 or XRCC1 were identified. CONCLUSIONS AOA2 and AOA4 were the most common forms of AOA in Brazil. Mutations in PIK3R5 and XRCC1 were not part of this genetic spectrum. © 2022 International Parkinson and Movement Disorder Society

<b><i>Introduction:</i></b> Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an efficient treatment of primary dystonia. Few studies have reported the effect of STN-DBS on secondary or acquired dystonia. <b><i>Methods:</i></b> We reported 2 patients with acquired dystonia treated by subthalamic DBS and followed up for 24 months, besides providing a systematic review and meta-analysis of published series. <b><i>Results/Conclusions:</i></b> Both patients had thalamic vascular or autoimmune lesions within the ventral and the pulvinar nuclei. A reduction of 67.2% on the Burke-Fahn-Marsden Dystonia Rating Scale and 90% improvement in disability scores were shown in the first patient, while the second patient showed a lower reduction in both dystonia symptoms (28.6%) and disability scores (44%). Both patients had a significant mean improvement in the quality of life (62.5% in the first and 57.9% in the second) and were free of drugs postoperatively. A systematic review showed a mean follow-up of 13 months in 19 patients, including our 2 patients. The review showed a significant Burke-Fahn-Marsden Dystonia Scale (BFMDRS) score median reduction of 19 points (52.4%; confidence interval [CI]: 11.0–25.0) and a significant median reduction of 6 points in disability scores (44.5%; 95% CI: 4.0–14.0), thereby improving quality of life. Age at surgery was inversely correlated with postoperative improvement (<i>r</i> = 0.63; <i>p</i> = 0.039). Hemidystonia had a nonsignificant better improvement than generalized dystonia (55.3 vs. 43.5%; <i>p</i> = 0.4433). No association between etiology and postoperative improvement and no serious complications were found. Although few data reported so far, subthalamic DBS is likely efficient for acquired dystonia.

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