Leigh syndrome in individuals bearing m.9185T>C MTATP6 variant. Is hyperventilation a factor which starts its development?

Leigh syndrome (LS), subacute necrotizing encephalomyelopathy is caused by various genetic defects, including m.9185T>C MTATP6 variant. Mechanism of LS development remains unknown. We report on the acid-base status of three patients with m.9185T>C related LS. At the onset, it showed respiratory alkalosis, reflecting excessive respiration effort (hyperventilation with low pCO2). In patient 1, the deterioration occurred in temporal relation to passive oxygen therapy. To the contrary, on the recovery, she demonstrated a relatively low respiratory drive, suggesting that a "hypoventilation" might be beneficial for m.9185T>C carriers. As long as circumstances of the development of LS have not been fully explained, we recommend to counteract hyperventilation and carefully dose oxygen in patients with m.9185T>C related LS.

Safety, tolerability, and efficacy of a widely available nusinersen program for Polish children with Spinal Muscular Atrophy.

Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder with limited treatment options. Nusinersen is the first disease-modifying therapy to treat children and adults with SMA. This study aimed to review the safety, tolerability, and efficacy data of a nusinersen treatment program in Polish children. A total of 298 patients aged from 0 to 18 years were included in the nusinersen treatment program in Poland between March 1 and September 20, 2019. All patients were prospectively followed for at least one year. The mean age at treatment onset was 6.9 years. SMA type 1 symptoms were reported in 127 patients (43.5%), SMA type 2 symptoms in 68 cases (23.3%), and SMA type 3 in 93 patients (31.8%). No patient met the inefficiency criteria defined in the program. One year after treatment initiation, all patients assessed by the CHOP-INTEND scale had improved or remained stable. The mean change in CHOP-INTEND score was an increase of 8.9 points between baseline and after one-year treatment (p < 0.001). Except for 2 fatal cases, not related to the treatment, no serious adverse events were reported. The results of our study indicate that treatment with nusinersen is beneficial for children with SMA regardless of their age, baseline functional status, or the number of SMN2 gene copies. Therapy with nusinersen was effective and well tolerated by patients.

The Clinical and Epidemiological Profile of Paediatric-Onset Multiple Sclerosis in Poland.

Background. Paediatric-onset MS (POMS) has a unique clinical profile compared to the more prevalent adult-onset MS. For this study, we aimed to determine the demographic and clinical characteristics of POMS in Poland as well as addressing some of its epidemiological aspects. Methods. A retrospective study was conducted based on the Polish Multiple Sclerosis Registry, considering a population of children and adolescents with MS (age ≤ 18 years). Data were collected by all 13 centres across Poland specializing in diagnosing and treating POMS. The actual course of the disease and its clinical properties were compared between child (≤12 years) and juvenile (>12 years) patients. MS onset and its prevalence were assessed at the end of 2019, stratified by age range. Results. A total of 329 paediatric or juvenile patients (228 girls, 101 boys) with a clinically definite diagnosis of MS, in conformity with the 2017 McDonald Criteria, were enrolled. For 71 children (21.6%), the first symptoms appeared before the age of 12. The female: male ratio increased with age, amounting to 1:1 in the ≤12 years group and to 2.9:1 in the >12 years group. In most cases, the disease had multi-symptomatic onset (31.3%), and its course was mostly of a relapsing−remitting character (95.7%). The initial Expanded Disability Status Score for both groups was 1.63 ± 1.1, whereas the annual relapse rate was 0.84 during the first 2 years. The time between the onset of symptoms and diagnosis was longer in the younger patients (8.2 ± 4.2 vs. 4.6 ± 3.6 months; p < 0.005). On 31 December 2019, the age-adjusted prevalence standardized to the European standard population was 5.19/100,000 (95% CI, 4.64−5.78). Significantly higher prevalence was noted in the 13−18 years group (7.12; 95% CI, 6.64−7.86) than in the 9−12 years group (3.41; 95% CI, 2.98−3.86) and the <9 years group (0.56; 95% CI, 0.46−0.64; p < 0.001). Conclusion. POMS commencing at the age of ≤12 years is rare, differing significantly from the juvenile-onset and adult MS in terms of clinical characteristics, course, and incidence, as stratified by gender.

Pediatric-onset multiple sclerosis in Poland: A registry-based retrospective cohort study.

BACKGROUND: Epidemiologic data on pediatric-onset multiple sclerosis (POMS) in Central and Eastern Europe are limited. The aim of this study was to determine the incidence, prevalence and the clinical features of POMS in Poland. METHODS: Registry-based retrospective study was conducted among Polish children population (age ≤ 18 years), between 1 January 2010 and 31 December 2019. A total of 329 pediatric or juvenile patients fulfilled the International Pediatric MS Study Group (IPMSSG) criteria for MS, reported to the Polish Multiple Sclerosis Registry, were considered for estimation of age- and sex-specific prevalence (per 100,000 persons), and incidence rates (per 100,000 person-years). The demographic data, clinical presentation and treatment strategies also were investigated. RESULTS: On December 31, 2019 in the database were collected data of 329 patients up to 18 years with POMS diagnosis (101 boys and 228 girls; mean age 15.3 ± 3.8 years). The age-adjusted prevalence standardized to the European Standard Population was 5.19/100,000 (95% confidence interval (CI), 4.64-5.78). A significantly higher prevalence was recorded in girls (7.41; 95% CI, 6.48-8.44) than in boys (3.08; 95% CI, 2.50-3.74; P<0.001). The mean annual standardized incidence in Poland between 2015 - 2019 was 0.77 (95%CI, 0.45-1.02) per 100,000 person-years. The highest overall standardized incidence 1.06 (95%CI, 0.82-1.34) was noted in 2018. Most of patients (95.7%) had relapsing-remitting disease with polysymptomatic onset in one-thirds of the cases, and 82.3% were treated with disease-modifying drugs. Family history of MS was reported in 26 cases (7.9%). CONCLUSION: In this first report of registry-based study from Poland an increasing prevalence and incidence of POMS was found during the last years. This temporal trend corroborate the findings of studies conducted elsewhere.

Exome Sequencing Reveals Novel Variants and Expands the Genetic Landscape for Congenital Microcephaly.

Congenital microcephaly causes smaller than average head circumference relative to age, sex and ethnicity and is most usually associated with a variety of neurodevelopmental disorders. The underlying etiology is highly heterogeneous and can be either environmental or genetic. Disruption of any one of multiple biological processes, such as those underlying neurogenesis, cell cycle and division, DNA repair or transcription regulation, can result in microcephaly. This etiological heterogeneity manifests in a clinical variability and presents a major diagnostic and therapeutic challenge, leaving an unacceptably large proportion of over half of microcephaly patients without molecular diagnosis. To elucidate the clinical and genetic landscapes of congenital microcephaly, we sequenced the exomes of 191 clinically diagnosed patients with microcephaly as one of the features. We established a molecular basis for microcephaly in 71 patients (37%), and detected novel variants in five high confidence candidate genes previously unassociated with this condition. We report a large number of patients with mutations in tubulin-related genes in our cohort as well as higher incidence of pathogenic mutations in MCPH genes. Our study expands the phenotypic and genetic landscape of microcephaly, facilitating differential clinical diagnoses for disorders associated with most commonly disrupted genes in our cohort.

Optic pathway gliomas in children with and without neurofibromatosis 1.

Optic pathway gliomas represent 2 to 5% of brain tumors in children. Frequently asymptomatic, sometimes they demonstrate rapid growth, causing considerable visual dysfunction, neurologic deficits, and endocrine disturbances. Most optic pathway gliomas are diagnosed in patients with neurofibromatosis 1. Little is known about their natural course; therefore, there are no clear and widely accepted guidelines for their treatment. This study compared the clinical manifestations and natural history of sporadic and neurofibromatosis 1-associated optic pathway gliomas with regard to age at diagnosis, gender, and findings on neurologic, ophthalmologic, and neuroradiologic examinations in 83 children with optic pathway gliomas: 51 children with neurofibromatosis 1 and 32 children without any symptoms or signs of neurofibromatosis 1. A prospective study was performed in 21 patients with neurofibromatosis 1. In the rest of the patients with neurofibromatosis 1 and in 32 children with sporadic tumors, the analysis was carried out retrospectively. There was an increased incidence of females in the group of patients with neurofibromatosis 1 with optic pathway gliomas compared with the entire group of patients with neurofibromatosis 1 remaining for follow-up (P = .013). All optic pathway gliomas were found in children below 10 years of age, slightly earlier in the group without neurofibromatosis 1 (median age 4.6 vs 4.8 years). Children with optic pathway gliomas associated with neurofibromatosis 1 had predominantly multifocal lesions (P = .0001), whereas in the group without neurofibromatosis 1, isolated chiasmal involvement was more common (P = .002). Children with sporadic gliomas had significantly more frequently increased intracranial pressure, decreased visual acuity, and abnormalities of fundus of the eye at the time of diagnosis. The radiologic progression, visual deterioration, and endocrinologic complications were documented on follow-up more commonly in children with sporadic tumors. Our findings support the concept that there is an earlier and more severe clinical presentation of optic pathway gliomas in children with sporadic tumors than in those associated with neurofibromatosis 1.