Integrative Approach to Predict Severity in Nonketotic Hyperglycinemia.

OBJECTIVE: Glycine encephalopathy, also known as nonketotic hyperglycinemia (NKH), is an inherited neurometabolic disorder with variable clinical course and severity, ranging from infantile epileptic encephalopathy to psychiatric disorders. A precise phenotypic characterization and an evaluation of predictive approaches are needed. METHODS: Longitudinal clinical and biochemical data of 25 individuals with NKH from the patient registry of the International Working Group on Neurotransmitter Related Disorders were studied with in silico analyses, pathogenicity scores, and molecular modeling of GLDC and AMT variants. RESULTS: Symptom onset (p < 0.01) and diagnosis occur earlier in life in severe NKH (p < 0.01). Presenting symptoms affect the age at diagnosis. Psychiatric problems occur predominantly in attenuated NKH. Onset age ≥ 3 months (66% specificity, 100% sensitivity, area under the curve [AUC] = 0.87) and cerebrospinal fluid (CSF)/plasma glycine ratio ≤ 0.09 (57% specificity, 100% sensitivity, AUC = 0.88) are sensitive indicators for attenuated NKH, whereas CSF glycine concentration ≥ 116.5µmol/l (100% specificity, 93% sensitivity, AUC = 0.97) and CSF/plasma glycine ratio ≥ 0.15 (100% specificity, 64% sensitivity, AUC = 0.88) are specific for severe forms. A ratio threshold of 0.128 discriminates the overlapping range. We present 10 new GLDC variants. Two mild variants resulted in attenuated, whereas 2 severe variants or 1 mild and 1 severe variant led to severe phenotype. Based on clinical, biochemical, and genetic parameters, we propose a severity prediction model. INTERPRETATION: This study widens the phenotypic spectrum of attenuated NKH and expands the number of pathogenic variants. The multiparametric approach provides a promising tool to predict disease severity, helping to improve clinical management strategies. ANN NEUROL 2022;92:292-303.

Efficacy and safety of empagliflozin in glycogen storage disease type Ib: Data from an international questionnaire.

PURPOSE: This paper aims to report collective information on safety and efficacy of empagliflozin drug repurposing in individuals with glycogen storage disease type Ib (GSD Ib). METHODS: This is an international retrospective questionnaire study on the safety and efficacy of empagliflozin use for management of neutropenia/neutrophil dysfunction in patients with GSD Ib, conducted among the respective health care providers from 24 countries across the globe. RESULTS: Clinical data from 112 individuals with GSD Ib were evaluated, representing a total of 94 treatment years. The median age at start of empagliflozin treatment was 10.5 years (range = 0-38 years). Empagliflozin showed positive effects on all neutrophil dysfunction-related symptoms, including oral and urogenital mucosal lesions, recurrent infections, skin abscesses, inflammatory bowel disease, and anemia. Before initiating empagliflozin, most patients with GSD Ib were on G-CSF (94/112; 84%). At the time of the survey, 49 of 89 (55%) patients previously treated with G-CSF had completely stopped G-CSF, and another 15 (17%) were able to reduce the dose. The most common adverse event during empagliflozin treatment was hypoglycemia, occurring in 18% of individuals. CONCLUSION: Empagliflozin has a favorable effect on neutropenia/neutrophil dysfunction-related symptoms and safety profile in individuals with GSD Ib.

Postauthorization safety study of betaine anhydrous.

Patient registries for rare diseases enable systematic data collection and can also be used to facilitate postauthorization safety studies (PASS) for orphan drugs. This study evaluates the PASS for betaine anhydrous (Cystadane), conducted as public private partnership (PPP) between the European network and registry for homocystinurias and methylation defects and the marketing authorization holder (MAH). Data were prospectively collected, 2013-2016, in a noninterventional, international, multicenter, registry study. Putative adverse and severe adverse events were reported to the MAH's pharmacovigilance. In total, 130 individuals with vitamin B6 nonresponsive (N = 54) and partially responsive (N = 7) cystathionine beta-synthase (CBS) deficiency, as well as 5,10-methylenetetrahydrofolate reductase (MTHFR; N = 21) deficiency and cobalamin C (N = 48) disease were included. Median (range) duration of treatment with betaine anhydrous was 6.8 (0-9.8) years. The prescribed betaine dose exceeded the recommended maximum (6 g/day) in 49% of individuals older than 10 years because of continued dose adaptation to weight; however, with disease-specific differences (minimum: 31% in B6 nonresponsive CBS deficiency, maximum: 67% in MTHFR deficiency). Despite dose escalation no new or potential risk was identified. Combined disease-specific treatment decreased mean ± SD total plasma homocysteine concentrations from 203 ± 116 to 81 ± 51 µmol/L (p < 0.0001), except in MTHFR deficiency. Recommendations for betaine anhydrous dosage were revised for individuals ≥ 10 years. PPPs between MAH and international scientific consortia can be considered a reliable model for implementing a PASS, reutilizing well-established structures and avoiding data duplication and fragmentation.

Phenotype, treatment practice and outcome in the cobalamin-dependent remethylation disorders and MTHFR deficiency: Data from the E-HOD registry.

AIM: To explore the clinical presentation, course, treatment and impact of early treatment in patients with remethylation disorders from the European Network and Registry for Homocystinurias and Methylation Defects (E-HOD) international web-based registry. RESULTS: This review comprises 238 patients (cobalamin C defect n = 161; methylenetetrahydrofolate reductase deficiency n = 50; cobalamin G defect n = 11; cobalamin E defect n = 10; cobalamin D defect n = 5; and cobalamin J defect n = 1) from 47 centres for whom the E-HOD registry includes, as a minimum, data on medical history and enrolment visit. The duration of observation was 127 patient years. In 181 clinically diagnosed patients, the median age at presentation was 30 days (range 1 day to 42 years) and the median age at diagnosis was 3.7 months (range 3 days to 56 years). Seventy-five percent of pre-clinically diagnosed patients with cobalamin C disease became symptomatic within the first 15 days of life. Total homocysteine (tHcy), amino acids and urinary methylmalonic acid (MMA) were the most frequently assessed disease markers; confirmatory diagnostics were mainly molecular genetic studies. Remethylation disorders are multisystem diseases dominated by neurological and eye disease and failure to thrive. In this cohort, mortality, thromboembolic, psychiatric and renal disease were rarer than reported elsewhere. Early treatment correlates with lower overall morbidity but is less effective in preventing eye disease and cognitive impairment. The wide variation in treatment hampers the evaluation of particular therapeutic modalities. CONCLUSION: Treatment improves the clinical course of remethylation disorders and reduces morbidity, especially if started early, but neurocognitive and eye symptoms are less responsive. Current treatment is highly variable. This study has the inevitable limitations of a retrospective, registry-based design.

Development and characterization of cell models harbouring mtDNA deletions for in vitro study of Pearson syndrome.

Pearson syndrome is a rare multisystem disease caused by single large-scale mitochondrial DNA deletions (SLSMDs). The syndrome presents early in infancy and is mainly characterised by refractory sideroblastic anaemia. Prognosis is poor and treatment is supportive, thus the development of new models for the study of Pearson syndrome and new therapy strategies is essential. In this work, we report three different cell models carrying an SLMSD: fibroblasts, transmitochondrial cybrids and induced pluripotent stem cells (iPSCs). All studied models exhibited an aberrant mitochondrial ultrastructure and defective oxidative phosphorylation system function, showing a decrease in different parameters, such as mitochondrial ATP, respiratory complex IV activity and quantity or oxygen consumption. Despite this, iPSCs harbouring 'common deletion' were able to differentiate into three germ layers. Additionally, cybrid clones only showed mitochondrial dysfunction when heteroplasmy level reached 70%. Some differences observed among models may depend on their metabolic profile; therefore, we consider that these three models are useful for the in vitro study of Pearson syndrome, as well as for testing new specific therapies. This article has an associated First Person interview with the first author of the paper.

Switching to Glycerol Phenylbutyrate in 48 Patients with Urea Cycle Disorders: Clinical Experience in Spain.

Background and objectives: Glycerol phenylbutyrate (GPB) has demonstrated safety and efficacy in patients with urea cycle disorders (UCDs) by means of its clinical trial program, but there are limited data in clinical practice. In order to analyze the efficacy and safety of GPB in clinical practice, here we present a national Spanish experience after direct switching from another nitrogen scavenger to GPB. Methods: This observational, retrospective, multicenter study was performed in 48 UCD patients (age 11.7 ± 8.2 years) switching to GPB in 13 centers from nine Spanish regions. Clinical, biochemical, and nutritional data were collected at three different times: prior to GPB introduction, at first follow-up assessment, and after one year of GPB treatment. Number of related adverse effects and hyperammonemic crisis 12 months before and after GPB introduction were recorded. Results: GPB was administered at a 247.8 ± 102.1 mg/kg/day dose, compared to 262.6 ± 126.1 mg/kg/day of previous scavenger (46/48 Na-phenylbutyrate). At first follow-up (79 ± 59 days), a statistically significant reduction in ammonia (from 40.2 ± 17.3 to 32.6 ± 13.9 µmol/L, p < 0.001) and glutamine levels (from 791.4 ± 289.8 to 648.6 ± 247.41 µmol/L, p < 0.001) was observed. After one year of GPB treatment (411 ± 92 days), we observed an improved metabolic control (maintenance of ammonia and glutamine reduction, with improved branched chain amino acids profile), and a reduction in hyperammonemic crisis rate (from 0.3 ± 0.7 to less than 0.1 ± 0.3 crisis/patients/year, p = 0.02) and related adverse effects (RAE, from 0.5 to less than 0.1 RAEs/patients/year p < 0.001). Conclusions: This study demonstrates the safety of direct switching from other nitrogen scavengers to GPB in clinical practice, which improves efficacy, metabolic control, and RAE compared to previous treatments.

[A study of epilepsy according to the age at onset and monitored for 3 years in a regional reference paediatric neurology unit]. / Estudio de las epilepsias según la edad de inicio, controladas durante 3 años en una unidad de neuropediatría de referencia regional.

OBJECTIVE: A study of epilepsy, according to the age at onset of the crisis and its causes, monitored by a Paediatric Neurology Unit over a period of three years. PATIENTS AND METHODS: Historical cohorts study was conducted by reviewing the Paediatric Neurology medical records data base of epileptic children followed-up from 1 January 2008 to 31 December 2010. RESULTS: A total of 4,595 children were attended during the study period. The diagnosis of epilepsy was established in 605 (13.17%): 277 (45.79%) symptomatic, 156 (25.79%) idiopathic, and 172 (28.43%) with cryptogenic epilepsy. Absence epilepsy and benign childhood epilepsy with centro-temporal spikes are the idiopathic epileptic syndromes most prevalent, and the most prevalent symptomatic epilepsies are prenatal encephalopathies. More than one-quarter (26.12%) of epilepsies began in the first year of life, and 67.72% were symptomatic. Refractory epilepsy was observed in 25.29%, 42.46% with cognitive impairment, 26.45% with motor involvement, and 9.92% with an autism spectrum disorder, being more frequent at an earlier age of onset. CONCLUSIONS: The absence of a universally accepted classification of epileptic syndromes makes tasks like this difficult, starting with the terminology. A useful classification would be aetiological, with two groups: a large group with established aetiology, or very likely genetic syndromes, and another with no established cause. The age of onset of epilepsy in each aetiological group helps in the prognosis, which is worsened by refractoriness and associated neurodevelopmental disorders, and are generally worse at an earlier onset and in certain aetiologies.

GNAO1 encephalopathy: further delineation of a severe neurodevelopmental syndrome affecting females.

BACKGROUND: De novo heterozygous mutations in the GNAO1 gene, encoding the Gα o subunit of G-proteins, are the cause of a severe neurodevelopmental disorder, featuring early infantile seizures, profound cognitive dysfunction and, occasionally, movement disorder (early infantile epileptic encephalopathy-17). METHODS: We report a further case of this association in a 20 month-old Spanish girl with neonatal-onset refractory seizures, progressive microcephaly, oral-lingual dyskinesia and nearly absent psychomotor development. We performed whole-exome sequencing, a computational structural analysis of the novel gene variant identified and reviewed the previously reported cases. RESULTS: Trio whole-exome-sequencing uncovered a de novo p.Leu199Pro GNAO1 mutation. Computational structural analysis indicates this novel variant adversely affects the stability of the G-protein heterotrimeric complex as a whole. Of note, our patient showed a sustained seizure reduction while on a ketogenic diet. CONCLUSIONS: With this observation, a total of twelve patients with GNAO1 encephalopathy have been reported. Oral-lingual dyskinesia and responsiveness of seizures to ketogenic diet are novel features. The distorted sex ratio (12/12 females) of the condition remains unexplained; a differential gender effect of the disruption of G-protein- mediated signal transduction on the developing brain can be hypothesized.

Encefalopatía, fallo renal y retinopatía. Déficit de CoQ10 por mutación de COQ8B / Encephalopathy, kidney failure and retinopathy. CoQ10 deficiency due to COQ8B mutation

No disponible

Deficiencia de lipasa ácida lisosomal: una causa poco reconocida de dislipemia y disfunción hepática / Lysosomal acid lipase deficiency: A rarely recognised cause of dyslipidaemia and liver dysfunction

No disponible

Estudio de las epilepsias según la edad de inicio, controladas durante 3 años en una unidad de neuropediatría de referencia regional / A study of epilepsy according to the age at onset and monitored for 3 years in a regional reference paediatric neurology unit

OBJETIVO: Estudio de las epilepsias según la edad de inicio de las crisis y la etiología, de los pacientes controlados en una unidad de neuropediatría durante 3 años. PACIENTES Y MÉTODOS: Estudio de cohortes históricas. Revisión de historias de niños con epilepsia de la base de datos de neuropediatría controlados del 1 de enero de 2008 al 31 de diciembre de 2010. RESULTADOS: De 4.595 ni˜nos atendidos en el periodo, se estableció el diagnóstico de epilepsia en 605 (13,17%), siendo 277 (45,79%) epilepsias sintomáticas, 156 (25,79%) idiopáticas y 172 (28,43%) criptogénicas. La epilepsia de ausencias y la epilepsia benigna de la infancia con paroxismos centrotemporales son los síndromes epilépticos idiopáticos con mayor prevalencia, y las encefalopatías prenatales las epilepsias sintomáticas más prevalentes. El 26,12% iniciaron su epilepsia el primer a˜no, siendo sintomáticas el 67,72%. Se han considerado refractarias el 25,29% de las epilepsias; el 42,46% asocia déficit cognitivo, el 26,45% afectación motora y el 9,92% trastorno del espectro autista, siendo más frecuentes a menor edad de inicio. CONCLUSIONES: La ausencia de una clasificación universalmente aceptada de los síndromes epilépticos dificulta trabajos como este, empezando por la terminología. Una clasificación útil es la etiológica, con 2 grupos: un gran grupo con las etiologías establecidas o síndromes genéticos muy probables, y otro de casos sin causa establecida. La edad de inicio de la epilepsia en cada grupo etiológico añade orientación pronóstica. El pronóstico de la epilepsia lo ensombrecen la refractariedad y las alteraciones asociadas del neurodesarrollo, siendo peor en general a más precoz inicio y en etiologías concretas

OBJECTIVE: A study of epilepsy, according to the age at onset of the crisis and its causes, monitored by a Paediatric Neurology Unit over a period of three years. PATIENTS AND METHODS: Historical cohorts study was conducted by reviewing the Paediatric Neurology medical records data base of epileptic children followed-up from 1 January 2008 to 31 December 2010. RESULTS: A total of 4,595 children were attended during the study period. The diagnosis of epilepsy was established in 605 (13.17%): 277 (45.79%) symptomatic, 156 (25.79%) idiopathic, and 172 (28.43%) with cryptogenic epilepsy. Absence epilepsy and benign childhood epilepsy with centro-temporal spikes are the idiopathic epileptic syndromes most prevalent, and the most prevalent symptomatic epilepsies are prenatal encephalopathies. More than one-quarter (26.12%) of epilepsies began in the first year of life, and 67.72% were symptomatic. Refractory epilepsy was observed in 25.29%, 42.46% with cognitive impairment, 26.45% with motor involvement, and 9.92% with an autism spectrum disorder, being more frequent at an earlier age of onset. CONCLUSIONS: The absence of a universally accepted classification of epileptic syndromes makes tasks like this difficult, starting with the terminology. A useful classification would be aetiological, with two groups: a large group with established aetiology, or very likely genetic syndromes, and another with no established cause. The age of onset of epilepsy in each aetiological group helps in the prognosis, which is worsened by refractoriness and associated neurodevelopmental disorders, and are generally worse at an earlier onset and in certain aetiologies

Repercusión clínica de la traslocación t(7; 15) (p22; q26) en varios miembros de una misma familia / Clinical impact of translocation t(7; 15) (p22; q26) on several family members

No disponible

Leucoencefalopatía difusa por infección congénita por citomegalovirus / No disponible

No disponible

Autoevaluación del cumplimiento del protocolo de manejo del traumatismo craneoencefálico en niños menores de 1 año en urgencias / No disponible

No disponible