RFC1: Motifs and phenotypes.

Biallelic intronic expansions (AAGGG)exp in intron 2 of the RFC1 gene have been shown to be a common cause of late-onset ataxia. Since their first description, the phenotypes, neurological damage, and pathogenic variants associated with the RFC1 gene have been frequently updated. Here, we review the various motifs, genetic variants, and phenotypes associated with the RFC1 gene. We searched PubMed for scientific articles published between March 1st, 2019, and January 15th, 2024. The motifs and phenotypes associated with the RFC1 gene are highly heterogeneous, making molecular diagnosis and clinical screening and investigation challenging. In this review we will provide clues to give a better understanding of RFC1 disease. We briefly discuss new methods for molecular diagnosis, the origin of cough in RFC1 disease, and research perspectives.

Indication for molecular testing by multiplex ligation-dependent probe amplification in parkinsonism.

BACKGROUND AND PURPOSE: The monogenic forms of Parkinson's disease represent <10% of familial cases and a still lower frequency of sporadic cases. However, guidelines to orient genetic testing are lacking. The aim was to establish the interest of multiplex ligation-dependent probe amplification (MLPA) as a primary screening test and to propose clinical criteria to guide genetic diagnostic tests for patients with suspected Mendelian Parkinson's disease. METHODS: In all, 567 patients with parkinsonism from 547 unrelated families were recruited and two MLPAs were performed for each. All pathogenic G2019S variants in the LRRK2 gene were confirmed by Sanger sequencing and the PRKN gene was screened for a second mutation in the cases of one heterozygous structural variant in the PRKN gene. RESULTS: The performance of MLPA was 51/567 (9%) for the entire cohort and included 27 (4.8%) LRRK2 G2019S mutations, 19 (3.4%) PRKN mutations and five (0.9%) SNCA locus duplications. The variables significantly associated with a positive test in the total cohort were North African ancestry (p < 0.0001), female sex (p = 0.004) and younger age at onset (p < 0.0008). CONCLUSIONS: Retrospective analysis allowed us to refine our indication criteria: (i) North African ancestry, (ii) an age at onset <40 years or (iii) a familial history of parkinsonism with at least one affected first-degree relative. Our study highlights the interest of MLPA testing for other parkinsonism cases with a family history, especially for patients with dementia with Lewy bodies or a multiple-system-atrophy-like phenotype.

Use of levodopa-carbidopa intestinal gel to treat patients with multiple system atrophy.

BACKGROUND: Levodopa-carbidopa intestinal gel (LCIG) is an effective treatment for late-stage Parkinson's disease (PD) but had not been evaluated in levodopa-responsive patients with the parkinsonian variant of multiple system atrophy (MSA-P) and motor fluctuations. We aimed to assess the safety of LCIG in MSA-P patients. METHODS: In a retrospective, single-center study, we analyzed clinical and treatment-related data for all patients with MSA-P or PD treated with LCIG between December 2004 and November 2017. Adverse events (AEs) were classified into three classes: AEs related to gastrointestinal effects or to the PEG-J procedure, AEs related to the device, and AEs related to the pharmacological effect of LCIG. RESULTS: 7 MSA-P and 63 PD patients had been treated with LCIG for a median [interquartile range] period of 31 [16;43] and 19 [8;45] months, respectively. There were no significant intergroup differences in safety. Enteral nutrition was introduced at the same time as LCIG treatment in 4 (57%) MSA-P patients. In the MSA-P and PD groups, LCIG was associated with a better Global Clinical Impression score and discontinuation of oral anti-parkinsonian drugs (in 43% and 27% of cases, respectively). CONCLUSIONS: LCIG treatment is feasible in MSA-P patients with severe motor complications. The safety profile is similar to that seen in PD.

Does ultrasound-guidance improve the outcome of botulinum toxin injections in cervical dystonia?

PURPOSE: Ultrasound-guided injections of botulinum neurotoxin in cervical dystonia have a number of theoretical advantages. However, their action has never been compared to that of non-guided injections. The objectives of the study were to compare the outcome of botulinum neurotoxin type A treatment in patients with idiopathic, focal cervical dystonia, according to two methods: inspection and palpation of anatomical landmarks (non-guided group) or ultrasound guidance (ultrasound-guided group). METHODS: We included consecutive patients in this single-center, prospective, real-life, non-randomized study. The outcomes were evaluated one month after the injections: Cervical Dystonia Impact Profile 58 (main outcome), Toronto Western Spasmodic Torticollis Rating Scale-2 (pain and disability subscores), Toronto Western Spasmodic Torticollis Rating Scale-PSYCH, patient-rated Clinical Global Impression - Improvement and adverse events. We used propensity score methods for statistical analysis; ten predefined confounding factors were used to build the propensity score. RESULTS: Sixty-three patients were included in the non-guided group, and 60 other patients in the ultrasound-guided group. We found no difference in main and secondary outcomes between the two study groups. CONCLUSION: This is the first direct comparison between ultrasound-guided and non-guided botulinum neurotoxin type A injections in patients with cervical dystonia. We hypothesize that ultrasound guidance made it possible to obtain the same results in the most severe (or the most demanding) patients as in the best responders. Further studies are still needed to assess the impact of botulinum neurotoxin injections into deep cervical muscles.

Anatomy-guided injections of botulinum neurotoxin in neck muscles: how accurate is needle placement?

BACKGROUND AND PURPOSE: In cervical dystonia, the accuracy of botulinum neurotoxin (BoNT) injections may influence the response to the treatment. METHODS: We used ultrasound to evaluate the accuracy of anatomy-guided injections of BoNT in the neck muscles. RESULTS: A total of 56 consecutive patients and 332 injections were evaluated. The overall accuracy was 76.6%. The lowest accuracy (67.9%) was observed for the splenius capitis muscle. CONCLUSIONS: Anatomic guidance of BoNT injections in the neck muscles is often inaccurate. Imaging guidance may improve the accuracy of BoNT injections in cervical dystonia.

Safety and effectiveness of levodopa-carbidopa intestinal gel for advanced Parkinson's disease: A large single-center study.

BACKGROUND: Treatment with levodopa-carbidopa intestinal gel (LCIG) can effectively relieve motor and non-motor symptoms in advanced Parkinson's disease (PD). However, adverse events (AEs) are frequent. OBJECTIVE: To describe AEs associated with LCIG treatment and the main reasons for treatment discontinuation. We also looked for factors that were potentially predictive of serious AEs and assessed the effectiveness of and satisfaction with LCIG. METHOD: We retrospectively analyzed data on AEs in patients treated with LCIG at a French university medical center. For patients still receiving treatment at last follow-up, effectiveness was assessed according to the Clinical Global Impression (CGI) scale and the Movement Disorders Society - Unified Parkinson's Disease Rating Scale motor score. RESULTS: Of the 63 patients treated with LCIG for a mean (range) of 19 months (8-47), 57 (90%) experienced at least one AE (340 AEs in total). Most of the AEs (in 69.8% of the patients) were related to percutaneous endoscopic gastrostomy with a jejunal tube (PEG-J) or affected the gastrointestinal tract (granuloma, leakage, or a local infection). Device-related AEs (such as PEG-J removal and device occlusion) were frequent (in 63.5% of patients). Forty-three patients (68%) required at least one additional endoscopic procedure. Dopatherapy-related AEs occurred in 30 patients (48%). Most of the AEs occurred long after treatment initiations, and only a small proportion led to discontinuation. On the CGI scale, 53 patients (84.4%) considered that their condition had improved during LCIG treatment. CONCLUSION: Despite the high frequency of AEs, patients with advanced PD gain clinical benefit from treatment with LCIG. This treatment requires a competent, multidisciplinary team on site.

Parkinson's disease associated with 22q11.2 deletion: Clinical characteristics and response to treatment.

BACKGROUND: While it is known that 22q11.2 microdeletions (22q11.2-del) increase the risk of Parkinson's disease (PD), the characteristics of PD associated with 22q11.2-del have not been specifically explored. OBJECTIVE: This report aimed to assess the clinical characteristics and treatment responses of PD patients with 22q11.2-del, and to describe any features that might lead neurologists to investigate the comorbidity. METHODS: Nine PD patients (eight men, one woman) with 22q11.2-del were followed at seven centers of the French PD Expert Network (Ns-Park). RESULTS: PD diagnosis was made before 22q11.2-del diagnosis in seven cases; their main characteristics were early onset (32-48 years) and good initial levodopa sensitivity, but with a course characterized by severe and early-onset levodopa-induced motor complications and psychiatric manifestations. Three patients received deep brain stimulation (DBS) that was effective. CONCLUSION: Searching for 22q11.2-del in PD patients presenting with suggestive features is relevant as the clinical presentation is similar to idiopathic PD, but with other associated characteristics, including a severe evolution. Results with DBS are similar to those reported for idiopathic PD.

[Continuous subcutaneous infusion of apomorphine in Parkinson's disease: retrospective analysis of a series of 81 patients]. / Le traitement par apomorphine en perfusion continue sous-cutanée dans la maladie de Parkinson : analyse rétrospective d'une série de 81 patients.

BACKGROUND: Continuous subcutaneous infusion of apomorphine (CAI) has shown efficacy in the treatment of motor fluctuations but its place in the therapeutic arsenal remains poorly defined in terms of indication, acceptability and long-term tolerance. Indeed, few studies have been carried out with a follow-up greater than 12 months. The main objective was to assess the quality of life of Parkinson's disease (PD) patients treated with CAI. We also evaluate the effectiveness on the motor fluctuations, the long-term tolerance of this treatment with its causes of discontinuation and the treatment regimens used. METHODS: We conducted a retrospective study of 81 PD patients treated with CAI between April 2003 and June 2012. Data were collected from medical records. A repeated measures analysis of variance by the linear mixed model was used (significance level: 5%). RESULTS: In August 2012, 27/81 patients were still treated with CAI with a mean duration of 28 months, 46/81 discontinued CAI (9 precociously), and 8 were lost to view. We didn't show improvement in the quality of life nor efficacy of CAI on the UPDRS IV score (P=0.54) and dyskinesia score (P=0.95). The CGI score patient also reflects this result with a majority response suggesting no significant change with CAI. We observed relative good cognitive and psychiatric tolerance. Adverse events were frequent but often benign. The average (±SD) rate of apomorphine was 3.15±1.71 mg/h and the oral dopaminergic treatment was decreased by 37.8%. DISCUSSION: The results are consistent with the literature except for the lack of efficiency on motor fluctuations which may be due to the use of too small doses of apomorphine. This seems to be a leading cause of discontinuation of CAI, especially when it is associated with side effects or important constraints. For better efficiency on motor fluctuations, we recommend the use of apomorphine at higher doses to obtain an optimal continuous dopaminergic stimulation.

[Trichloroethylene intoxication presenting with temporal seizures]. / Crises temporales symptomatiques d'une intoxication au trichloroéthylène.

INTRODUCTION: Trichloroethylene (TCE) is extensively used as a degreasing agent in the metal industry and as a solvent for organic compounds. Its neurotoxicity (with respect to both the peripheral and central nervous systems) is now widely acknowledged. OBSERVATION: Here, we report the case of a 32-year-old male drug addict presenting temporal seizures after "huffing" TCE (i.e. voluntary inhalation). The patient also deve loped a "psycho-organic syndrome" which included cognitive dysfunction (with memory disorders in particular) and personality changes. These disorders had not been noticed by the patient's wife prior to the last episode of inhalation. Four months later, the cognitive disorders had stabilized and no further seizures had been observed. CONCLUSION: The patient's overall clinical picture (notably featuring neuropsychological disorders) and electroencephalographic and brain imaging data argue in favor of a selective effect of TCE on the temporal lobe.