Functional and clinical relevance of novel mutations in a large cohort of patients with Cockayne syndrome

BACKGROUND: Cockayne syndrome (CS) is a rare, autosomal recessive multisystem disorder characterised by prenatal or postnatal growth failure, progressive neurological dysfunction, ocular and skeletal abnormalities and premature ageing. About half of the patients with symptoms diagnostic for CS show cutaneous photosensitivity and an abnormal cellular response to UV light due to mutations in either the ERCC8/CSA or ERCC6/CSB gene. Studies performed thus far have failed to delineate clear genotype-phenotype relationships. We have carried out a four-centre clinical, molecular and cellular analysis of 124 patients with CS

Unravelling the etiology of sporadic late-onset cerebellar ataxia in a cohort of 205 patients: a prospective study

BACKGROUND: Despite recent progress in the field of genetics, sporadic late-onset (> 40 years) cerebellar ataxia (SLOCA) etiology remains frequently elusive, while the optimal diagnostic workup still needs to be determined. We aimed to comprehensively describe the causes of SLOCA and to discuss the relevance of the investigations. METHODS: We included 205 consecutive patients with SLOCA seen in our referral center. Patients were prospectively investigated using exhaustive clinical assessment, biochemical, genetic, electrophysiological, and imaging explorations. RESULTS: We established a diagnosis in 135 (66%) patients and reported 26 different causes for SLOCA, the most frequent being multiple system atrophy cerebellar type (MSA-C) (41%). Fifty-one patients (25%) had various causes of SLOCA including immune-mediated diseases such as multiple sclerosis or anti-GAD antibody-mediated ataxia; and other causes, such as alcoholic cerebellar degeneration, superficial siderosis, or Creutzfeldt-Jakob disease. We also identified 11 genetic causes in 20 patients, including SPG7 (n = 4), RFC1-associated CANVAS (n = 3), SLC20A2 (n = 3), very-late-onset Friedreich's ataxia (n = 2), FXTAS (n = 2), SCA3 (n = 1), SCA17 (n = 1), DRPLA (n = 1), MYORG (n = 1), MELAS (n = 1), and a mitochondriopathy (n = 1) that were less severe than MSA-C (p < 0.001). Remaining patients (34%) had idiopathic late-onset cerebellar ataxia which was less severe than MSA-C (p < 0.01). CONCLUSION: Our prospective study provides an exhaustive picture of the etiology of SLOCA and clues regarding yield of investigations and diagnostic workup. Based on our observations, we established a diagnostic algorithm for SLOCA

10q26 deletion syndrome: a French cohort study

International audience10q26 deletion syndrome (OMIM #609625) is a rare autosomal dominant genetic disorder with about 100 patients reported. Most cases are sporadic. Global development delay, short stature, microcephaly and typical facial appearance with triangular face, large forehead, low-set malformed ears, hypertelorism, prominent nose and a thin vermilion of the upper lip constitute the main clinical features. The clinical spectrum is very heterogeneous and neurobehavioral manifestations, deafness, limb malformations, cardiac and urogenital abnormalities can be associated. Thus, patients with 10q26 chromosomal deletion need multidisciplinary management strategies from birth. One of the main reasons for this heterogeneity is the variety of 10qter region chromosomal deletions summarized into the “10q26 deletion syndrome”. Various studies proposed critical regions to explain the main phenotype (Yatzenko et al., 2009; Choucair et al., 2015; Lin S et al., 2016) or more specific features (Vera-Carbonell et al., 2015; Choucair et al., 2015). In addition, these studies proposed about 20 genes of interest such as DOCK1 and FGFR2 to explain the different clinical features observed. We report a French ACLF cohort of 35 patients from 9 centers presenting 10q26 complete or partial deletions (size: 64kb to 12.5Mb), complex chromosomal rearrangement and derivative chromosomes diagnosed using DNA-array, to bring a further insight of the genotype/phenotype correlation

Highlighting the Dystonic Phenotype Related to GNAO1

BACKGROUND: Most reported patients carrying GNAO1 mutations showed a severe phenotype characterized by early‐onset epileptic encephalopathy and/or chorea. OBJECTIVE: The aim was to characterize the clinical and genetic features of patients with mild GNAO1‐related phenotype with prominent movement disorders. METHODS: We included patients diagnosed with GNAO1‐related movement disorders of delayed onset (>2 years). Patients experiencing either severe or profound intellectual disability or early‐onset epileptic encephalopathy were excluded. RESULTS: Twenty‐four patients and 1 asymptomatic subject were included. All patients showed dystonia as prominent movement disorder. Dystonia was focal in 1, segmental in 6, multifocal in 4, and generalized in 13. Six patients showed adolescence or adulthood‐onset dystonia. Seven patients presented with parkinsonism and 3 with myoclonus. Dysarthria was observed in 19 patients. Mild and moderate ID were present in 10 and 2 patients, respectively. CONCLUSION: We highlighted a mild GNAO1‐related phenotype, including adolescent‐onset dystonia, broadening the clinical spectrum of this condition. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Societ