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Objective:To observe the clinical features of eyes in children with methylmalonic acidemia (MMA).Methods:A retrospective clinical case study. From June 2019 to June 2022, 13 children with MMA visited on the Department of Ophthalmology of Henan Children's Hospital were included in the study. The anterior segment and fundus were examined under surface or general anesthesia. Best corrected visual acuity (BCVA) and refraction were performed in 9 cases; fluorescein fundus angiography (FFA) was performed in 3 cases; flash electroretinogram (FERG) was performed in 6 cases; flash visual evoked potential (FVEP) was detected in 6 cases; optical coherence tomography (OCT) was performed in 3 cases.Results:Among the 13 pediatric patients with methylmalonic acidemia, 6 cases were male and 7 cases were female. The average age at first visit was 45 months. All cases suffered from hyperhomocysteinemia; 9 cases were with epilepsy; 2 cases were with infantile spasms; 11 cases were with stunting, 13 cases were with repeated pulmonary infection during growth period; 4 cases were with hydrocephalus; 1 cases was with hypertension and renal insufficiency. Genetic dectection results of 8 cases were recorded, MMACHC:c.609G>A:p.W203* mutation site was found in all cases. One case was accompanied by corneal ulcer. There were 10 cases with nystagmus, 4 cases with macular degeneration, 3 cases with hyperopic refractive error and esotropia. Nine cases underwent BCVA examination, BCVA was light perception-0.6. In OCT, 2 cases of 3 cases showed retinal thinning and photoreceptor cell layer atrophy in the macular area. In FFA, 2 cases of 3 cases showed circular transparent fluorescence in the macular area. Five cases of 6 cases who with FVEP had different degrees of P100 peak time delay and decreased amplitude, and 4 cases of 6 cases with FERG had decrease of a and b wave in light and dark adaptation. Conclusions:The clinical phenotypes of eyes in children with MMA are various and the severity was different; most of them are accompanied by nystagmus, and the fundus lesions are common in the characteristic bovine eye like macular region. Those with macular disease have severe visual impairment.
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Late onset methylmalonic acidemia (MMA) is a rare genetic metabolic disease.This case is a 46 year old adult patient with MMA complicated with hyperhomocysteinemia.It starts with progressive limb weakness and mental abnormality, and has dysuria and respiratory failure.Neurological examination showed decreased muscle strength of limbs and pyramidal tract sign.The levels of blood homocysteine and urinary methylmalonic acid increased significantly.Head, neck, thoracolumbar magnetic resonance imaging showed abnormal signals in the spinal cord from the level of foramen magnum to the level of lumbar 1 vertebral body.Two heterozygous variants of mmachc were found by gene detection: c: 609G>A, c: 349G>A, consistent with cobalamin C deficiency.Treat with L-carnitine, vitamin B12 and betaine.The patients′ mental symptoms, limb muscle strength and respiratory failure were improved, and the level of blood homocysteine also decreased significantly.
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Objective To explore the clinical manifestations, treatment and outcomes of patients with c. 482G>A ( p. R161Q ) variant of MMACHC gene in cblC type methylmalonic acidemia ( MMA ) . Methods The clinical manifestations, mass spectrometry results, genotypes, treatment and outcomes of 75 patients with cblC type MMAcarryingc.482G>A(p.R161Q)variantwereretrospectivelyanalyzed.Results Ofthe75patients,57(76％) were from newborn screening and one of them had an onset. Among the rest 18 unscreened patients, 2 were diagnosed after their full sisters' or brothers' diagnosis, the others were clinical patients. There were 17 clinical patients, with the medium age of onset 12 years old (10 days～26 years old). 12 late onset patients (70.6％) presented with poor academic performance, memory loss, poor expression, and decreased exercise capacity, while 5 early onset patients (29.4％) presented with convulsion and delay of development. All patients were vitamin B12-responsive. The levels of blood propionylcarnitine, the ratio of propionylcarnitine to acetylcarnitine, urinary methylmalonic acid and methyldecanoic acid, and plasma homocysteine were significantly decreased after treatment (P< 0.01). All patients diagnosed from newborn screening had normal development. However, only 3 clinical patients had a rather normal outcomes and the others remained different levels of intelligence and ( or ) motor dysfunction after treatment. Conclusion The c.482G>A ( p. R161Q) variant of MMACHC gene is associated with late onset cblC type MMA. Patients with this variant have a better response to hydroxycobalamin than other variants. The outcome of patients diagnosed from the newborn screening is good. When symptoms occur, the disability rate is often high. Therefore, newborn screening is a recommended method to prevent this disease.
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Objective@#To report on clinical characteristics and genetic findings in 15 Chinese patients with methylmalonic acidemia (MMA).@*Methods@#For the 15 MMA patients detected by tandem mass spectrometry, genetic analysis was carried out in twelve pedigrees. Clinical characteristics, genetic finding, treatment and outcomes were retrospectively analyzed.@*Results@#The main features of the patients included poor feeding, recurrent vomiting, lethargy, seizure and development retardation. Blood propionylcarnitine (except for 3 patients), its ratio with acetylcarnitine, and urine methylmalonic acid were increased in all patients. Twelve patients were diagnosed genetically, which included 7 with MUT variants, 4 with MMACHC variants, and 1 with MMAB variant. Nine MUT variants were detected, among which c. 1159A>C, 753+ 1delGinsTGGTTATTA and c. 504del were novel. Six known pathogenic MMACHC variants and two novel MMAB variants (c.289_290delGG, c. 566G>A) were also detected. Seven patients died of metabolic crises within a year, others had improved effectively following the treatment, but had mild to severe growth delay and/or developmental retardation.@*Conclusion@#The clinical manifestation of MMA are complex. Most patients have variants of the MUT and MMACHC genes. High mortality may occur before one year of age.
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Objective To analyze the clinical features and gene mutation in mthylmalonic acidemia (MMA) accompanied by homocysteinemia (cblC), and review the relevant literatures. Methods The clinical features of 3 cases of MMA diagnosed by gene detection were retrospectively analyzed, and meanwhile the pertinent literatures of pathogenesis of MMA, especially combined with late-onset cblC and its gene detection, were reviewed. Results Patient 1 (26 days old) suffered from intermittent convulsions for 3 days, with isosuccinic acid 175.8 μmol/L, C3/C2 rate 1.363, homocysteine >?65 μmol/L and abnormal EEG. MMACHC gene detection found an exon deficiency (delEXON1), which has not been reported. Patient 2 ( 12 year old) was hospitalized for limb shaking, hyperspasmia and vomiting. His isosuccinic acid level was 334.3 μmol/L, C3/?C2 rate was 0.37, homocysteine >?65 μmol/L, and had abnormal EEG. MMACHC gene detection found the mutations of c.482G?>?A and c.609G?>?A. Patient 3 was hospitalized for intermittent convulsions for 20 days, whose isosuccinic acid, C3/?C2 rate, and homocysteine were increased. MMACHC gene detection found the mutations of c.394C?>?T and c.540del8 and c.540del8 had not been reported. Review of literatures discovered that MMA was combined with epileptic seizure in some patents, which further validate that the mutation in MMACHC gene c.482G?>?A may be related to the late-onset of cblC. Conclusions Gene detection contributes to the diagnosis of MMA; the mutation of MMACHC gene c.482G>A may be related to the late-onset of cblC; delEXON1 and c.540del8 are new mutations which have not been reported.
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PURPOSE: Methylmalonic aciduria (MMA) and propionic aciduria (PA) are inborn errors in the catabolism of branched-chain amino acids. The study was undertaken to investigate the genotypes and clinical features of Korean patients with MMA and PA. METHODS: This study examined 12 patients with MMA and eight with PA. We analyzed various clinical features, laboratory findings, treatments, and neuro-developmental outcomes. Diagnoses were based on the presence of characteristic compounds detected by amino acid analysis in serum and organic acid analysis in urine. Mutation analysis was performed in the genes of MUT, MMAA, MMAB, and MMACHC for MMA and PCCA and PCCB for PA. RESULTS: Among the 20 patients, six patients were diagnosed before one month of age and nine patients were diagnosed after the newborn period. Five patients were diagnosed via a neonatal screening test. Patients with early-onset forms had more severe illness at presentation and generally poor outcomes. A favorable outcome was obtained in 55% patients; most of them were of a late-onset type or diagnosed by neonatal mass screening test without symptoms. Genotypes were confirmed in all patients with MMA. We detected 11 different mutations by MUT gene analysis in 10 patients, and three different mutations in MMACHC genes in two patients. PCCA and PCCB gene mutations were identified in 14 of the 16 alleles, in eight patients with PA. CONCLUSION: Organic aciduria is a fatal disease; however, better outcomes are expected whenever early diagnosis and prompt management are made possible. Mutation analysis is useful for confirming diagnoses and planning management strategies.
Subject(s)
Humans , Infant, Newborn , Alleles , Amino Acids, Branched-Chain , Chromones , Diethylpropion , Early Diagnosis , Genotype , Mass Screening , Neonatal Screening , Propionic AcidemiaABSTRACT
PURPOSE: Methylmalonic aciduria (MMA) and propionic aciduria (PA) are inborn errors in the catabolism of branched-chain amino acids. The study was undertaken to investigate the genotypes and clinical features of Korean patients with MMA and PA. METHODS: This study examined 12 patients with MMA and eight with PA. We analyzed various clinical features, laboratory findings, treatments, and neuro-developmental outcomes. Diagnoses were based on the presence of characteristic compounds detected by amino acid analysis in serum and organic acid analysis in urine. Mutation analysis was performed in the genes of MUT, MMAA, MMAB, and MMACHC for MMA and PCCA and PCCB for PA. RESULTS: Among the 20 patients, six patients were diagnosed before one month of age and nine patients were diagnosed after the newborn period. Five patients were diagnosed via a neonatal screening test. Patients with early-onset forms had more severe illness at presentation and generally poor outcomes. A favorable outcome was obtained in 55% patients; most of them were of a late-onset type or diagnosed by neonatal mass screening test without symptoms. Genotypes were confirmed in all patients with MMA. We detected 11 different mutations by MUT gene analysis in 10 patients, and three different mutations in MMACHC genes in two patients. PCCA and PCCB gene mutations were identified in 14 of the 16 alleles, in eight patients with PA. CONCLUSION: Organic aciduria is a fatal disease; however, better outcomes are expected whenever early diagnosis and prompt management are made possible. Mutation analysis is useful for confirming diagnoses and planning management strategies.