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1.
Genet Med ; 26(8): 101165, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38762772

RESUMEN

PURPOSE: Galactose mutarotase (GALM) deficiency was first reported in 2019 as the fourth type of galactosemia. This study aimed to investigate the clinical and genotypic spectra of GALM deficiency. METHODS: This was a questionnaire-based retrospective survey conducted in Japan between February 2022 and March 2023. RESULTS: We identified 40 patients with GALM deficiency in Japan (estimated prevalence: 1:181,835). Four of 38 patients (10.5%) developed cataracts, which resolved with lactose restriction in 3 out of 4 patients. Transient transaminitis was the most common symptom (23.1%). All of the patients followed lactose restriction; discontinuation of the restriction after infancy did not cause any complications. Moreover, none of the participants experienced long-term complications. Two variants, GALM NM_138801.3: c.294del and c.424G>A, accounted for 72.5% of the identified pathogenic variants. The patients showed moderately elevated blood galactose levels with lactose intake; however, the elevation was lower than that observed in galactokinase deficiency. CONCLUSION: GALM deficiency is characterized by a similar but milder phenotype and lower blood galactose elevation than in galactokinase deficiency. Diagnosis and initiation of lactose restriction in early infancy should be essential for prevention of cataracts, especially in cases of irreversible opacity.


Asunto(s)
Galactosa , Galactosemias , Fenotipo , Humanos , Japón/epidemiología , Galactosemias/genética , Galactosemias/epidemiología , Femenino , Masculino , Preescolar , Lactante , Estudios Retrospectivos , Niño , Adolescente , Adulto , Encuestas y Cuestionarios , Mutación/genética , Genotipo , Catarata/genética , Catarata/epidemiología , Catarata/sangre
2.
Ann Neurol ; 93(2): 330-335, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36333996

RESUMEN

Infantile striatonigral degeneration is caused by a homozygous variant of the nuclear-pore complex (NPC) gene NUP62, involved in nucleo-cytoplasmic trafficking. By querying sequencing-datasets of patients with dystonia and/or Leigh(-like) syndromes, we identified 3 unrelated individuals with biallelic variants in NUP54. All variants clustered in the C-terminal protein region that interacts with NUP62. Associated phenotypes were similar to those of NUP62-related disease, including early-onset dystonia with dysphagia, choreoathetosis, and T2-hyperintense lesions in striatum. In silico and protein-biochemical studies gave further evidence for the argument that the variants were pathogenic. We expand the spectrum of NPC component-associated dystonic conditions with localized basal-ganglia abnormalities. ANN NEUROL 2023;93:330-335.


Asunto(s)
Distonía , Trastornos Distónicos , Proteínas de Complejo Poro Nuclear , Humanos , Cuerpo Estriado , Distonía/genética , Trastornos Distónicos/genética , Neostriado , Proteínas de Complejo Poro Nuclear/genética
3.
Neuropediatrics ; 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39008988

RESUMEN

X-linked myotubular myopathy (XLMTM) is a rare congenital myopathy that commonly manifests with liver involvement. In most XLMTM cases, disease-causing variants have been identified in the myotubularin gene (MTM1) on chromosome Xq28, which encodes myotubularin protein (MTM1). The impairment of mitochondrial respiratory chain (MRC) enzyme activity in muscle has been observed in the XLMTM mouse model. Though several reports mentioned possible mechanisms of liver involvement in XLMTM patients and animal models, the precise underlying mechanisms remain unknown, and there is no report focused on mitochondrial functions in hepatocytes in XLMTM. We encountered two patients with XLMTM who had liver involvement. We measured MRC enzyme activities in two muscle biopsy specimens, and one liver specimen from our patients to investigate whether MTM1 variants cause MRC dysfunction and whether mitochondrial disturbance is associated with organ dysfunction. MRC enzyme activities decreased in skeletal muscles but were normal in the liver. In our patients, the impaired MRC enzyme activity found in muscle is consistent with previously reported mechanisms that the loss of MTM1-desmin intermediate filament and MTM1-IMMT (a mitochondrial membrane protein) interaction led to the mitochondrial dysfunction. However, our study showed that liver involvement in XLMTM may not be associated with mitochondrial dysfunction.

4.
Pediatr Transplant ; 28(1): e14659, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38012111

RESUMEN

BACKGROUND: POLG is one of several nuclear genes associated with mitochondrial DNA maintenance defects and is a group of diseases caused by mitochondrial DNA deficiency that results in impaired adenosine triphosphate production and organ dysfunction. Myocerebrohepatopathy spectrum (MCHS) is the most severe and earliest presentation of POLG mutations, and liver transplantation (LT) for MCHS has never been reported. CASE PRESENTATION: The patient was a 3-month-old boy with acute liver failure and no neurological manifestations (e.g., seizures). We performed a living donor LT using a left lateral segment graft from his father. The postoperative course was uneventful. Subsequently, a homozygous POLG mutation (c.2890C>T, p. R964C) was identified by multigene analysis of neonatal/infantile intrahepatic cholestasis. Moreover, respiratory chain complex I, II, and III enzyme activities and the ratio of mtDNA to nuclear DNA in the liver were reduced. Therefore, we considered that these clinical manifestations and examination findings met the definition for MCHS. During meticulous follow-up, the patient had shown satisfactory physical growth and mental development until the time of writing this report. CONCLUSION: We presumed that the absence of remarkable neurologic manifestations prior to LT in patients with MCHS is a good indication for LT and contributes to a better prognosis in the present case.


Asunto(s)
Fallo Hepático Agudo , Trasplante de Hígado , Masculino , Humanos , Recién Nacido , Lactante , ADN Polimerasa Dirigida por ADN/genética , ADN Polimerasa gamma/genética , Donadores Vivos , Mutación , ADN Mitocondrial/genética
5.
J Med Genet ; 60(10): 1006-1015, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37055166

RESUMEN

BACKGROUND: Enoyl-CoA hydratase short-chain 1 (ECHS1) is an enzyme involved in the metabolism of branched chain amino acids and fatty acids. Mutations in the ECHS1 gene lead to mitochondrial short-chain enoyl-CoA hydratase 1 deficiency, resulting in the accumulation of intermediates of valine. This is one of the most common causative genes in mitochondrial diseases. While genetic analysis studies have diagnosed numerous cases with ECHS1 variants, the increasing number of variants of uncertain significance (VUS) in genetic diagnosis is a major problem. METHODS: Here, we constructed an assay system to verify VUS function for ECHS1 gene. A high-throughput assay using ECHS1 knockout cells was performed to index these phenotypes by expressing cDNAs containing VUS. In parallel with the VUS validation system, a genetic analysis of samples from patients with mitochondrial disease was performed. The effect on gene expression in cases was verified by RNA-seq and proteome analysis. RESULTS: The functional validation of VUS identified novel variants causing loss of ECHS1 function. The VUS validation system also revealed the effect of the VUS in the compound heterozygous state and provided a new methodology for variant interpretation. Moreover, we performed multiomics analysis and identified a synonymous substitution p.P163= that results in splicing abnormality. The multiomics analysis complemented the diagnosis of some cases that could not be diagnosed by the VUS validation system. CONCLUSIONS: In summary, this study uncovered new ECHS1 cases based on VUS validation and omics analysis; these analyses are applicable to the functional evaluation of other genes associated with mitochondrial disease.


Asunto(s)
Enfermedades Mitocondriales , Humanos , Fenotipo , Enfermedades Mitocondriales/diagnóstico , Enfermedades Mitocondriales/genética , Mutación/genética , Enoil-CoA Hidratasa/genética , Enoil-CoA Hidratasa/metabolismo , Pruebas Genéticas
6.
Genet Med ; 25(6): 100314, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36305855

RESUMEN

PURPOSE: This study aimed to define the genotypic and phenotypic spectrum of reversible acute liver failure (ALF) of infancy resulting from biallelic pathogenic TRMU variants and determine the role of cysteine supplementation in its treatment. METHODS: Individuals with biallelic (likely) pathogenic variants in TRMU were studied within an international retrospective collection of de-identified patient data. RESULTS: In 62 individuals, including 30 previously unreported cases, we described 47 (likely) pathogenic TRMU variants, of which 17 were novel, and 1 intragenic deletion. Of these 62 individuals, 42 were alive at a median age of 6.8 (0.6-22) years after a median follow-up of 3.6 (0.1-22) years. The most frequent finding, occurring in all but 2 individuals, was liver involvement. ALF occurred only in the first year of life and was reported in 43 of 62 individuals; 11 of whom received liver transplantation. Loss-of-function TRMU variants were associated with poor survival. Supplementation with at least 1 cysteine source, typically N-acetylcysteine, improved survival significantly. Neurodevelopmental delay was observed in 11 individuals and persisted in 4 of the survivors, but we were unable to determine whether this was a primary or a secondary consequence of TRMU deficiency. CONCLUSION: In most patients, TRMU-associated ALF was a transient, reversible disease and cysteine supplementation improved survival.


Asunto(s)
Fallo Hepático Agudo , Fallo Hepático , Adolescente , Niño , Preescolar , Humanos , Lactante , Adulto Joven , Acetilcisteína/uso terapéutico , Fallo Hepático/tratamiento farmacológico , Fallo Hepático/genética , Fallo Hepático Agudo/tratamiento farmacológico , Fallo Hepático Agudo/genética , Proteínas Mitocondriales/genética , Mutación , Estudios Retrospectivos , ARNt Metiltransferasas/genética
7.
Mol Genet Metab ; 140(1-2): 107703, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37802748

RESUMEN

OBJECTIVE: To examine whether it is possible to screen for bile acid synthesis disorders (BASDs) including peroxisome biogenesis disorder 1a (PBD1A) and Niemann-Pick type C1 (NPC1) at the time of newborn mass screening by measuring the intermediary metabolites of bile acid (BA) synthesis. METHODS: Patients with 3ß-hydroxy-ΔSuchy et al. (2021)5-C27-steroid dehydrogenase/isomerase (HSD3B7) deficiency (n = 2), 3-oxo-ΔPandak and Kakiyama (n.d.)4-steroid 5ß-reductase (SRD5B1) deficiency (n = 1), oxysterol 7α-hydroxylase (CYP7B1) deficiency (n = 1), PBD1A (n = 1), and NPC1 (n = 2) with available dried blood spot (DBS) samples collected in the neonatal period were included. DBSs from healthy neonates at 4 days of age (n = 1055) were also collected for the control. Disease specific BAs were measured by newly optimized liquid chromatography-tandem mass spectrometry with short run cycle (5-min/run). The results were validated by comparing with those obtained by the conventional condition with longer run cycle (76-min/run). RESULTS: In healthy specimens, taurocholic acid and cholic acid were the two major BAs which constituted approximately 80% in the measured BAs. The disease marker BAs presented <10%. In BASDs, the following BAs were determined for the disease specific markers: Glyco/tauro 3ß,7α,12α-trihydroxy-5-cholenoic acid 3-sulfate for HSD3B7 deficiency (>70%); glyco/tauro 7α,12α-dihydroxy-3-oxo-4-cholenoic acid for SRD5B1 deficiency (54%); tauro 3ß-hydroxy-5-cholenoic acid 3-sulfate for CYP7B1 deficiency (94%); 3α,7α,12α-trihydroxy-5ß-cholestanoic acid for PBD1A (78%); and tauro 3ß,7ß-dihydroxy-5-cholenoic acid 3-sulfate for NPC1 (26%). *The % in the parenthesis indicates the portion found in the patient's specimen. CONCLUSIONS: Early postnatal screening for BASDs, PBD1A and NPC1 is feasible with the described DBS-based method by measuring disease specific BAs. The present method is a quick and affordable test for screening for these inherited diseases.


Asunto(s)
Hepatopatías , Síndrome de Zellweger , Recién Nacido , Humanos , Ácidos y Sales Biliares , Tamizaje Neonatal , Esteroides , Sulfatos
8.
J Hum Genet ; 68(9): 649-652, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37246162

RESUMEN

Approximately 80% of rare diseases have a genetic cause, and an accurate genetic diagnosis is necessary for disease management, prognosis prediction, and genetic counseling. Whole-exome sequencing (WES) is a cost-effective approach for exploring the genetic cause, but several cases often remain undiagnosed. We combined whole genome sequencing (WGS) and RNA sequencing (RNA-seq) to identify the pathogenic variants in an unsolved case using WES. RNA-seq revealed aberrant exon 4 and exon 6 splicing of ITPA. WGS showed a previously unreported splicing donor variant, c.263+1G>A, and a novel heterozygous deletion, including exon 6. Detailed examination of the breakpoint indicated the deletion caused by recombination between Alu elements in different introns. The proband was found to have developmental and epileptic encephalopathies caused by variants in the ITPA gene. The combination of WGS and RNA-seq may be effective in diagnosing conditions in proband who could not be diagnosed using WES.


Asunto(s)
Familia , Pirofosfatasas , Humanos , Secuenciación del Exoma , Secuenciación Completa del Genoma , Exones , Análisis de Secuencia de ARN
9.
J Inherit Metab Dis ; 2023 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-37681292

RESUMEN

Citrin deficiency is an autosomal recessive disorder caused by a defect of citrin resulting from mutations in the SLC25A13 gene. Intrahepatic cholestasis and various metabolic abnormalities, including hypoglycemia, galactosemia, citrullinemia, and hyperammonemia may be present in neonates or infants in the "neonatal intrahepatic cholestasis caused by citrin deficiency" (NICCD) form of the disease. Because at present, newborn screening (NBS) for citrin deficiency using citrulline levels in dried blood spots (DBS) can only detect some of the patients, we tried to develop a new evaluation system to more reliably detect newborns with citrin deficiency utilizing parameters already in place in present NBS methods. To achieve this goal, we re-analyzed NBS profiles of amino acids and acylcarnitines in 96 NICCD patients, who were diagnosed through selective screening or positive family history. Hereby, we identified the combined evaluation of arginine (Arg), citrulline (Cit), isoleucine+leucine (Ile + Leu), tyrosine (Tyr), free carnitine (C0) / glutarylcarnitine (C5-DC) ratio in DBS as potentially sensitive to diagnose citrin deficiency in pre-symptomatic newborns. In particular, a scoring system using threshold levels for Arg (≥9 µmol/L), Cit (≥ 39 µmol/L), Ile + Leu (≥ 99 µmol/L), Tyr (≥ 96 µmol/L) and C0/C5-DC ratio (≥327) was significantly effective to detect newborns who later developed NICCD, and could thus be implemented in existing NBS programs at no extra analytical costs whenever citrin deficiency is considered to become a novel target disease.

10.
J Med Genet ; 59(4): 351-357, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-33811136

RESUMEN

BACKGROUND: Progressive cavitating leukoencephalopathy (PCL) is thought to result from mutations in nuclear genes affecting mitochondrial function and energy metabolism. To date, mutations in two subunits of complex I, NDUFS1 and NDUFV1, have been reported to be related to PCL. METHODS: Patients underwent clinical examinations, brain MRI, skin biopsy and muscle biopsy. Whole-genome or whole-exome sequencing was performed on the index patients from two unrelated families with PCL. The effects of the mutations were examined through complementation of the NDUFV2 mutation by cDNA expression. RESULTS: The common clinical features of the patients in this study were recurring episodes of acute or subacute developmental regression that appeared in the first years of life, followed by gradual remissions and prolonged periods of stability. MRI showed leukoencephalopathy with multiple cavities. Three novel NDUFV2 missense mutations were identified in these families. Complex I deficiency was confirmed in affected individuals' fibroblasts and a muscle biopsy. Functional and structural analyses revealed that these mutations affect the structural stability and function of the NDUFV2 protein, indicating that defective NDUFV2 function is responsible for the phenotypes in these individuals. CONCLUSIONS: Here, we report the clinical presentations, neuroimaging and molecular and functional analyses of novel mutations in NDUFV2 in two sibling pairs of two Chinese families presenting with PCL. We hereby expand the knowledge on the clinical phenotypes associated with mutations in NDUFV2 and the genotypes causative for PCL.


Asunto(s)
Leucoencefalopatías , Enfermedades Mitocondriales , NADH Deshidrogenasa , Exoma , Humanos , Leucoencefalopatías/diagnóstico por imagen , Leucoencefalopatías/genética , Enfermedades Mitocondriales/genética , Mutación , NADH Deshidrogenasa/genética , Secuenciación del Exoma
11.
Clin Exp Nephrol ; 27(3): 288-294, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36574104

RESUMEN

BACKGROUND: High-risk screening for Fabry disease in dialysis patients is an effective means for reducing the number of undiagnosed cases. However, such screening has not been conducted in Chiba Prefecture, Japan. Herein, we aimed to estimate the prevalence of Fabry disease among patients undergoing hemodialysis in Chiba Prefecture by high-risk screening using α-galactosidase A (αGal A) activity measurement, and examine the hemodialysis effect on αGal A activity. METHODS: Patients who underwent maintenance hemodialysis at 25 facilities in Chiba Prefecture were recruited. The αGal A activity was measured using the dried blood spot (DBS) test as the first screening. If the enzyme activity was lower than the cut-off, the second screening was performed with the same method before and after dialysis. RESULTS: Overall, 2924 patients (2036 men and 888 women) were included from which 94 cases (45 men and 48 women) showed decreased αGAL activity in the first screening and 3 (two men and one women) in the second screening. Genetic testing was performed in 3 patients, and the c.1078G > A mutation in GLA gene was detected in one male patient (0.03%). There has been a statistically significant decrease in αGal A activity of DBS at post-dialysis compared to that at pre-dialysis (20.5 ± 10.4 pmol/h/disk and 22.7 ± 11.5 pmol/h/disk, p < 0.0001). CONCLUSION: The prevalence of Fabry disease among patients undergoing hemodialysis in Chiba Prefecture was estimated as 0.03%. This is the first time that dialysis has been shown to affect the αGal A activity.


Asunto(s)
Enfermedad de Fabry , Humanos , Masculino , Femenino , Enfermedad de Fabry/genética , Japón/epidemiología , Diálisis Renal , alfa-Galactosidasa/genética , Pruebas Genéticas
13.
J Hum Genet ; 67(3): 143-148, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34650211

RESUMEN

Fanconi syndrome is a functional disorder of the proximal tubule, characterized by pan-aminoaciduria, glucosuria, hypophosphatemia, and metabolic acidosis. With the advancements in gene analysis technologies, several causative genes are identified for Fanconi syndrome. Several mitochondrial diseases cause Fanconi syndrome and various systemic symptoms; however, it is rare that the main clinical symptoms in such disorders are Fanconi syndrome without systematic active diseases like encephalomyopathy or cardiomyopathy. In this study, we analyzed two families exhibiting Fanconi syndrome, developmental disability and mildly elevated liver enzyme levels. Whole-exome sequencing (WES) detected compound heterozygous known and novel BCS1L mutations, which affect the assembly of mitochondrial respiratory chain complex III, in both cases. The pathogenicity of these mutations has been established in several mitochondria-related functional analyses in this study. Mitochondrial diseases with isolated renal symptoms are uncommon; however, this study indicates that mitochondrial respiratory chain complex III deficiency due to BCS1L mutations cause Fanconi syndrome with developmental disability as the primary indications.


Asunto(s)
Síndrome de Fanconi , Enfermedades Mitocondriales , ATPasas Asociadas con Actividades Celulares Diversas/genética , Niño , Discapacidades del Desarrollo/genética , Complejo III de Transporte de Electrones/genética , Síndrome de Fanconi/genética , Humanos , Enfermedades Mitocondriales/genética , Mutación
14.
J Inherit Metab Dis ; 45(3): 431-444, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35142380

RESUMEN

Citrin deficiency is an autosomal recessive disorder caused by mutations in the SLC25A13 gene. The disease can present with age-dependent clinical manifestations: neonatal intrahepatic cholestasis by citrin deficiency (NICCD), failure to thrive, and dyslipidemia by citrin deficiency (FTTDCD), and adult-onset type II citrullinemia (CTLN2). As a nationwide study to investigate the clinical manifestations, medical therapy, and long-term outcome in Japanese patients with citrin deficiency, we collected clinical data of 222 patients diagnosed and/or treated at various different institutions between January 2000 and December 2019. In the entire cohort, 218 patients were alive while 4 patients (1 FTTDCD and 3 CTLN2) had died. All patients <20 years were alive. Patients with citrin deficiency had an increased risk for low weight and length at birth, and CTLN2 patients had an increased risk for growth impairment during adolescence. Liver transplantation has been performed in only 4 patients (1 NICCD, 3 CTLN2) with a good response thereafter. This study reports the diagnosis and clinical course in a large cohort of patients with citrin deficiency and suggests that early intervention including a low carbohydrate diet and MCT supplementation can be associated with improved clinical course and long-term outcome.


Asunto(s)
Colestasis Intrahepática , Citrulinemia , Dislipidemias , Transportadores de Anión Orgánico , Adolescente , Adulto , Colestasis Intrahepática/etiología , Colestasis Intrahepática/terapia , Citrulinemia/diagnóstico , Citrulinemia/genética , Citrulinemia/terapia , Insuficiencia de Crecimiento , Humanos , Recién Nacido , Japón , Proteínas de Transporte de Membrana Mitocondrial/genética , Mutación
15.
J Inherit Metab Dis ; 45(6): 1143-1150, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36053827

RESUMEN

Pathogenic mitochondrial DNA heteroplasmy has mainly been assessed with bulk sequencing in individuals with mitochondrial disease. However, the distribution of heteroplasmy at the single-cell level in skin fibroblasts obtained from individuals, together with detailed clinical and biochemical information, remains to be investigated. We used the mitochondrial DNA single-cell assay for the transposase-accessible chromatin sequencing method. Skin fibroblasts were obtained from six individuals with mitochondrial disease and pathogenic m.3243A>G variants of differing severity. Different distributions of heteroplasmy at the single-cell level were identified in skin fibroblasts from all six individuals. Four individuals with different outcomes showed similar averaged heteroplasmy rates with normal mitochondrial respiratory chain enzyme activity, while the distribution of single-cell heteroplasmy patterns differed among the individuals. This study showed different heteroplasmy distribution patterns at the single-cell level in individuals with the m.3243A>G variant, who had a similar averaged heteroplasmy rates with normal mitochondrial respiratory chain enzyme activity. Whether such different heteroplasmy distribution patterns explain the different clinical outcomes should be assessed further in future studies. Measuring heteroplasmy of pathogenic mitochondrial DNA variants at the single-cell level could be important in individuals with mitochondrial disease.


Asunto(s)
ADN Mitocondrial , Enfermedades Mitocondriales , Humanos , ADN Mitocondrial/genética , Heteroplasmia , Enfermedades Mitocondriales/genética , Mitocondrias/genética
16.
Neuropediatrics ; 53(1): 65-68, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34448181

RESUMEN

KARS encodes lysyl-tRNA synthetase, which is essential for protein translation. KARS mutations sometimes cause impairment of cytoplasmic and mitochondrial protein synthesis, and sometimes lead to progressive leukodystrophies with mitochondrial signature and psychomotor regression, and follow a rapid regressive course to premature death. There has been no disease-modifying therapy beyond supportive treatment. We present a 5-year-old male patient with an asymmetrical leukodystrophy who showed overt evidence of mitochondrial dysfunction, including elevation of lactate on brain MR spectroscopy and low oxygen consumption rate in fibroblasts. We diagnosed this patient's condition as KARS-related leukodystrophy with cerebral calcification, congenital deafness, and evidence of mitochondrial dysfunction. We employed a ketogenic diet as well as multiple vitamin supplementation with the intention to alleviate mitochondrial dysfunction. The patient showed alleviation of his psychomotor regression and even partial restoration of his abilities within 4 months. This is an early report of a potential disease-modifying therapy for KARS-related progressive leukodystrophy without appreciable adverse effects.


Asunto(s)
Sordera , Dieta Cetogénica , Lisina-ARNt Ligasa , Preescolar , Humanos , Lisina-ARNt Ligasa/genética , Lisina-ARNt Ligasa/metabolismo , Masculino , Mitocondrias/genética , Mitocondrias/metabolismo , Mutación
17.
Int Heart J ; 63(5): 970-977, 2022 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-36104228

RESUMEN

Hypertrophic cardiomyopathy is a common cardiac complication in mitochondrial disorders, and the morbidity rate in neonatal cases is up to 40%. The mortality rate within 3 months for neonatal-onset mitochondrial cardiomyopathy is known to be high because there is currently no established treatment.We report the case of a male infant with neonatal-onset mitochondrial disorder presenting lactic acidosis and hypertrophic cardiomyopathy. Genetic analysis of the patient revealed recurrent m.13513G>A, p.Asp393Asn in mitochondrially encoded NADH dehydrogenase 5 gene (MT-ND5). Low-dose propranolol was initially administered for cardiomyopathy; however, he developed hypertrophic obstructive cardiomyopathy (HOCM) at 3 months of age. To reduce the risk of hypoglycemia associated with high-dose propranolol, cibenzoline, a class Ia antiarrhythmic drug, was added at a dose of 2.5 mg/kg/day and increased weekly to 7.5 mg/kg/day with monitoring of the blood concentration of cibenzoline. Left ventricular outflow tract stenosis (LVOTS) dramatically improved from 5.4 to 1.3 m/second in LVOTS peak velocity after 6 weeks, without notable adverse effects. The plasma N-terminal pro-brain natriuretic peptide level decreased from 65,854 to 10,044 pg/mL. Furthermore, myocardial hypertrophy also improved, as the left ventricular mass index decreased from 173.1 to 108.9 g/m2 after 3 months of the treatment.The administration of cibenzoline, in conjunction with low-dose propranolol, may serve an effective treatment for HOCM in infantile patients with mitochondrial disorders.


Asunto(s)
Antiarrítmicos , Cardiomiopatía Hipertrófica , Antiarrítmicos/uso terapéutico , Cardiomiopatía Hipertrófica/complicaciones , Cardiomiopatía Hipertrófica/diagnóstico , Cardiomiopatía Hipertrófica/tratamiento farmacológico , Constricción Patológica , Humanos , Imidazoles , Recién Nacido , Masculino , NADH Deshidrogenasa/farmacología , NADH Deshidrogenasa/uso terapéutico , Propranolol/farmacología , Propranolol/uso terapéutico , Función Ventricular Izquierda
18.
Hum Mutat ; 42(11): 1422-1428, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34405929

RESUMEN

Isolated complex I deficiency is the most common cause of pediatric mitochondrial disease. Exome sequencing (ES) has revealed many complex I causative genes. However, there are limitations associated with identifying causative genes by ES analysis. In this study, we performed multiomics analysis to reveal the causal variants. We here report two cases with mitochondrial complex I deficiency. In both cases, ES identified a novel c.580G>A (p.Glu194Lys) variant in NDUFV2. One case additionally harbored c.427C>T (p.Arg143*), but no other variants were observed in the other case. RNA sequencing showed aberrant exon splicing of NDUFV2 in the unsolved case. Genome sequencing revealed a novel heterozygous deletion in NDUFV2, which included one exon and resulted in exon skipping. Detailed examination of the breakpoint revealed that an Alu insertion-mediated rearrangement caused the deletion. Our report reveals that combined use of transcriptome sequencing and GS was effective for diagnosing cases that were unresolved by ES.


Asunto(s)
Elementos Alu , Complejo I de Transporte de Electrón/deficiencia , Eliminación de Gen , Genoma Humano , Mutación INDEL , Enfermedades Mitocondriales/genética , NADH Deshidrogenasa/genética , Análisis de Secuencia de ARN/métodos , Complejo I de Transporte de Electrón/genética , Femenino , Humanos , Lactante , Masculino , Enfermedades Mitocondriales/diagnóstico , Linaje
19.
Am J Hum Genet ; 103(2): 221-231, 2018 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-30057030

RESUMEN

Bloom syndrome, caused by biallelic mutations in BLM, is characterized by prenatal-onset growth deficiency, short stature, an erythematous photosensitive malar rash, and increased cancer predisposition. Diagnostically, a hallmark feature is the presence of increased sister chromatid exchanges (SCEs) on cytogenetic testing. Here, we describe biallelic mutations in TOP3A in ten individuals with prenatal-onset growth restriction and microcephaly. TOP3A encodes topoisomerase III alpha (TopIIIα), which binds to BLM as part of the BTRR complex, and promotes dissolution of double Holliday junctions arising during homologous recombination. We also identify a homozygous truncating variant in RMI1, which encodes another component of the BTRR complex, in two individuals with microcephalic dwarfism. The TOP3A mutations substantially reduce cellular levels of TopIIIα, and consequently subjects' cells demonstrate elevated rates of SCE. Unresolved DNA recombination and/or replication intermediates persist into mitosis, leading to chromosome segregation defects and genome instability that most likely explain the growth restriction seen in these subjects and in Bloom syndrome. Clinical features of mitochondrial dysfunction are evident in several individuals with biallelic TOP3A mutations, consistent with the recently reported additional function of TopIIIα in mitochondrial DNA decatenation. In summary, our findings establish TOP3A mutations as an additional cause of prenatal-onset short stature with increased cytogenetic SCEs and implicate the decatenation activity of the BTRR complex in their pathogenesis.

20.
Mol Genet Metab ; 133(1): 63-70, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33741270

RESUMEN

Patients with citrin deficiency during the adaptation/compensation period exhibit diverse clinical features and have characteristic diet of high protein, high fat, and low carbohydrate. Japanese cuisine typically contains high carbohydrate but evaluation of diet of citrin-deficient patients in 2008 showed a low energy intake and a protein:fat:carbohydrate (PFC) ratio of 19:44:37, which indicates low carbohydrate consumption rate. These findings prompted the need for diet intervention to prevent the adult onset of type II citrullinemia (CTLN2). Since the publication of the report about 10 years ago, patients are generally advised to eat what they wish under active dietary consultation and intervention. In this study, citrin-deficient patients and control subjects living in the same household provided answers to a questionnaire, filled-up a maximum 6-day food diary, and supplied physical data and information on medications if any. To study the effects of the current diet, the survey collected data from 62 patients and 45 controls comparing daily intakes of energy, protein, fat, and carbohydrate. Food analysis showed that patient's energy intake was 115% compared to the Japanese standard. The confidence interval of the PFC ratio of patients was 20-22:47-51:28-32, indicating higher protein, higher fat and lower carbohydrate relative to previous reports. The mean PFC ratio of female patients (22:53:25) was significantly different from that of male patients (20:46:34), which may explain the lower frequency of CTLN2 in females. Comparison of the present data to those published 10 years ago, energy, protein, and fat intakes were significantly higher but the amount of carbohydrate consumption remained the same. Regardless of age, most patients (except for adolescents) consumed 100-200 g/day of carbohydrates, which met the estimated average requirement of 100 g/day for healthy individuals. Finally, patients were generally not overweight and some CTLN2 patients were underweight although their energy intake was higher compared with the control subjects. We speculate that high-energy of a low carbohydrate diet under dietary intervention may help citrin-deficient patients attain normal growth and prevent the onset of CTLN2.


Asunto(s)
Proteínas de Unión al Calcio/genética , Citrulinemia/dietoterapia , Metabolismo Energético/fisiología , Transportadores de Anión Orgánico/genética , Adolescente , Adulto , Proteínas de Unión al Calcio/deficiencia , Metabolismo de los Hidratos de Carbono/fisiología , Carbohidratos/administración & dosificación , Citrulinemia/epidemiología , Citrulinemia/metabolismo , Citrulinemia/patología , Grasas de la Dieta/administración & dosificación , Grasas de la Dieta/metabolismo , Ingestión de Alimentos/fisiología , Femenino , Humanos , Japón/epidemiología , Masculino , Proteínas de Transporte de Membrana Mitocondrial/genética , Transportadores de Anión Orgánico/deficiencia , Proteínas/administración & dosificación , Proteínas/metabolismo
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