Usher syndrome with methylmalonic acidemia and homocysteine in an infant / 中华围产医学杂志

A case of Usher syndrome with methylmalonic acidemia and homocysteine is reported. The patient was a two-month-old and small for gestational age male infant hospitalized for "feeding difficulties" during the neonatal period. The baby boy presented hypotonia, microcephaly, and hearing loss after birth. Genetic test found compound heterozygous mutations of c.482G>A and c.567dup in MMACHC, and both were pathogenic mutations inherited from his parents. Moreover, the patient also had compound heterozygous variants at c.2802T>G and c.14017T>C of USH2A gene. The former was suspected to be pathogenic, and the latter was of unknown clinical significance. Both were from the parents. Usher syndrome and methylmalonic acidemia with homocysteine were clinically diagnosed. Followed up to the age of two, the child was found with moderate mental retardation, while the physical development was comparable to that of the same age group.

Screening and gene mutations analysis for neonates with methylmalonic aciduria / 中华围产医学杂志

Objective To investigate the characteristics of neonatal methylmalonic aciduria (MMA)regarding clinical manifestations,laboratory findings,gene mutations,treatments and prognosis.Methods Acylcamitine levels in blood samples of 207 308 neonates born from January 2016 to December 2017 in Xuzhou were detected by liquid chromatography tandem mass spectrometry and the abnormal results were further confirmed by detecting organic acids in urine samples with gas chromatography-mass spectrometry and gene sequencing analysis.Patients with isolated MMA were treated with dietary control and levocarnitine,while those complicated by homocysteinemia were treated with vitamin B12,levocarnitine,glycine betaine and calcium folinate.Clinical manifestations,laboratory findings,imaging features,genotypes,treatments and prognosis of patients with MMA were retrospectively analyzed.Paired sample t-test was applied for statistical analysis.Results MMA was eventually diagnosed in 12 patients,among which three were isolated MMA and nine were complicated by homocysteinemia.The three isolated MMA cases failed to response to vitamin B12 treatment without any symptoms on diagnosis.However,vitamin B12 was effective for the other nine patients,among which four had no clinical symptoms on diagnosis and five had manifestations such as slow response,recurrent vomiting,poor feeding,dyspnea,anemia and jaundice.Abnormal results of cranial MRI included bilateral basal ganglia damage,enlarged extracranial space,ventriculomegaly and changes in white matter.All patients underwent genetic analysis and three were found with MUT gene mutations and nine with MMACHC gene mutations.MUT gene mutations were classified into five types,including c.I106G＞A,c.1880A＞G,c.441T＞A,c.581C＞T and c.1741C＞T.Eight types of MMACHC gene mutations were identified,including c.609G＞A,c.658_660delAAG,c.482G＞A,c.1A＞G,c.567dupT,c.80A＞G,c.276+1G＞A and c.228_23 l delTGAC.Two mutations,c.276+lG＞A and c.228 23 ldelTGAC,were novel mutations.The most common mutation in MMACHC gene was c.609G＞A,followed by c.658_660delAAG and c.482G＞A.One of the isolated MMA patients died after refusing treatments and the other two showed significant decrease in serum propionylcarnitine,propionylcarnitine to acetylcarnitine ratio,serum homocysteine and methylmalonic acid and methylcitric acid in urine after treatment.Moreover,of the two patients who were alive at follow-up,one experienced normal growth and development and the other suffered from growth retardation.The ratio of propionylcamitine to acetylcarnitine and the levels of serum propionylcarnitine,serum homocysteine and methylmalonic acid and methylcitric acid in urine were significantly decreased in the nine patients with MMA complicated by homocystinuria after one month of treatment [0.88±0.35 vs 0.13±0.05,(7.12±1.90) μ mol/L vs (3.18±1.08) μ mol/L,(136.48±38.14) μ mol/L vs (34.41±17.33) μmol/L,103.51±69.62vs 5.35±2.15 and 7.95±6.88 vs 1.02±0.48,t=-6.166,-6.687,-12.941,-4.208 and-3.015,respectively,all P＜0.05].Two deaths,three asymptomatic and four psychomotor retardation patients were reported during follow-up.Conclusions Newborn screening with liquid chromatography tandem mass spectrometry is important for early diagnosis of MMA.MMACHC gene defects are the main causes of MMA in Xuzhou area and the predominant one is c.609G＞A mutation.Prognosis of MMA might be related to disease type,age of onset and patient's reactivity to vitamin B12.

MUT genetic analysis in isolated methylmalonic acidemia pedigrees and its application in prenatal diagnosis / 中华围产医学杂志

Objective To analyze the mutation of MUT with Sanger sequencing technology to explore the feasibility of its application in prenatal diagnosis.Methods MUT sequencing was performed in 24 pedigrees who had history of isolated methylmalonic acidemia (MMA) babies and came to the First Affiliated Hospital of Zhengzhou University and Newborn Screening Center of Maternal and Child Health Hospital of He'nan Province between October 2012 and June 2015 for genetic counseling.Meanwhile,another 100 cases of normal controls also had their MUT gene sequence analyzed.After confirming the genotype of each pedigree,we collected the villi of nine high-risk fetuses in nine pedigrees whose parents were prepared for prenatal diagnosis.Results Totally,25 kinds of MUT gene mutations were identified among the 24 isolated MMA pedigrees,in which 11 were novel mutations including one nonsense mutation [c.616C＞T(p.Q206X)],six missense mutations [c.613G＞A(p.E205K),c.894T＞G(p.1298N),c.1009T＞C(p.F337L),c.1154G＞T(p.L385W),c.1663G＞A(p.A555T) and c.1675G＞A(p.R559G) and four frame shift mutations [c.626-627insC(p.P209Pfs*2),c.755-756insA(p.H252Qfs*6),c.756-757insA(p.M253Nfs*5) and c.1581-1582insA(p.A528Ifs*4)].None of the above mutations was detected in the controls.Finally,among the nine pedigrees for prenatal diagnosis,two were determined to have normal MUT gene,four were found to be heterozygous mutation carriers of MUT gene and three were confirmed as complex heterozygous or homozygous mutation carriers.Families of fetus who had normal MUT gene or fetuses who were carriers chose to continue the pregnancy,while those who had heterozygous mutation of MUT gene chose termination.The results of follow-up of newborns were consistent with that of prenatal diagnosis.Conclusions We found two novel mutations in MUT gene that might lead to isolated MMA.And Sanger sequencing technology for MUT gene sequencing analysis might effectively avoid the birth of isolated MMA children.

MMACHC gene mutation analysis in the prenatal diagnosis of methylmalonic aciduria with homocystinuria / 中华检验医学杂志

Objective To analyse MMACHC mutations for 45 pedigrees with combined methylmalonic aciduria and homocyctinuria by Sanger sequencing, and to discuss the utility of prenatal genetic diagnosis for these pedigrees.Method Peripheral blood was collected from 45 probands and their parents from 2012-2015 in Genetic Counselling Clinic of the First Affiliated Hospital of Zhengzhou University, and the DNA were extracted from the blood.Then the coding sequence of MMACHC gene was amplified by PCR, and the PCR products were further sequenced to detect mutations for each pedigree.For 12 families, chorionic villus sampling was performed on the pregnant women to make prenatal genetic diagnosis.Result There were 14 distinct mutations detected in the 45 pedigrees, and the most frequent mutations are c.609G>A(W203X),c.658-660delAAG(K220del)and c.80A>G (Q27A).Two of those mutations have not been reported before:one is a splicing site mutation c.81+1G>A;while the other is a missense mutation c.665A>G,p.Y222C.Most mutations were found in exon 4.Among the 12 pedigrees who received prenatal diagnosis, 2 fetuses were normal, 7 fetuses were carriers of heterozygous mutation, and the other 3 fetuses were patients with compound heterozygous mutation or homozygous mutation.The couples whose fetuses were normal or carriers continued the gestation, while the couples whose fetuses were patients decided to terminate the pregnancy.After delivery, the outcome of the fetuses was the same as the prenatal diagnose results.Conclusion Two novel mutations of MMACHC were identified and prenatal genetic diagnosis helps to avoid the delivery of combined methylmalonic aciduria and homocyctinuria patients.

Prenatal diagnosis of methylmalonic acidemia by amniotic fluid metabolites analysis using mass spectrometry / 中华围产医学杂志

Objective To investigate the effect of tandem mass spectrometry and gas chromatography-mass spectrometry to make prenatal diagnosis of methylmalonic acidemia (MMA) by detecting organic acid and acylcarnitine in amniotic fluid.Methods From October 11,2007 to December 20,2014,131 pregnant women with MMA proband received prenatal diagnosis of MMA in Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (case group).Another 120 cases of pregnant women for conventional prenatal diagnosis at the same period were as control group.The pregnant women of two groups had the amniocentesis at 16 to 20 weeks of gestation.The levels of propionylcarnitine(C3) and acetylcarnitine(C2)in amniotic fluid were detected by tandem mass spectrometry.The methylmalonic acid and methylcitrate acid were detected by gas chromatography-mass spectrometry.MMA gene of cells in amniotic fluid of eighty fetuses with proband clearly diagnosed were detected by gene testing.Data were analyzed by Wilcoxon test.Results In case group,29 fetuses were found positive for higher level of C3,C3/C2,methylmalonic acid and methylcitrate acid compared with normal reference value,and the detected rate of fetal MMA was 22.1％(29/131).The levels of C3 and C3 / C2 in amniotic fluid of these 29 cases were higher than those in control group[8.13(2.42-16.70) vs 1.04(0.52-3.40) μmol/L,Z =-8.313; 0.77(0.30-1.79) vs 0.10(0.05-0.22),Z=-8.374; P ＜ 0.05 respectively].The levels of methylmalonic acid and methylcitrate acid were also higher[9.13(1.68-61.78) vs 0.00(0.00-1.31) mmol/mol Crea,Z=-11.348; 0.58(0.00-1.90) vs 0.05(0.00-0.52) mmol/mol Crea,Z=-6.632,P ＜ 0.05 respectively].For the other 102 cases in case group,the levels of C3,C3/C2,methylmalonic acid and methylcitrate acid were not higher than normal reference value,and were similar to those in control group (P ＞ 0.05); while they were lower than those of positive MMA fetuses (all P ＜ 0.05).Among 29 positive fetuses,16 fetuses were detected MMA gene,five were diagnosed as MUT forms of MMA and 11 were MMACHC forms of MMA.In 102 MMA negative fetuses,64 fetuses were detected MMA gene,44 were found one mutant site and 20 were found no gene mutation.The coincidence rate between gene detecting and mass spectrometry was 100％(80/80).Conclusions Mass spectrometry could be used to measure the C3,methylmalonic acid and methylcitrate acid levels in amniotic fluid of pregnant women with MMA proband to make prenatal diagnosis.

Adultos jóvenes con deficiencia de metilentetrahidrofolato reductasa y aciduria etilenmalónica. Reporte de dos casos y revisión de tema / Female adults with ethylenmalonic aciduria and methylentretrahydropholate reductase deficiency: two cases report and review the literature / Adultos jovens com deficiência de metilentetrahidrofolato reductasa e aciduria etilenmalónica. Reporte de dois casos e revisão de tema

RESUMENLa combinación de la Aciduria etilmalónica y la homocistinuria son desórdenes del metabolismo heredados con un amplio espectro de manifestaciones clínicas que se pueden presentar desde la infancia hasta los adultos mayores. Sin embargo, con la detección temprana de estas enfermedades, en el periodo neonatal, se tendría la oportunidad de mejorar la calidad de vida de los pacientes afectados.

The impact of genomics in clinical medicine has been significant in recent years. Up to 2012, more than 3,000 genetic conditions have been implicated in clinical medicine. Today, with the new methodology of genome sequencing (next-generation sequencing (NGS) and comparative genomic sequencing (CGH), Mendelian conditions have been identified, as well as their role in genetic variations and polygenetic multifactorial disorders that affect the clinical prognosis and response to treatment.The integration of these diagnostic approaches in clinical practice requires an understanding of the basic principles of heredity, genome organization and molecular genetics. Generally, these conditions are single-gene disorders (also known as monogenic disorders), meaning that a single gene mutation is responsible for the disease.The genetic screening test analyzes hundreds of mutations for recessive genetic diseases. This test informs whether or not such mutations are present, which may lead to large-scale genotyping in children using multiple molecular probes.We report two cases of young adult women with symptoms and multiple medical consultations with disease recurrence and uncertain diagnosis, who underwent genetic testing and were determined to be carriers of heterozygous and homozygous mutant ethylmalonic aciduria and methylenetetrahydrofolate reductase deficiency, which could be responsible, in part, for their confusing symptoms.

A combinação da Aciduria etilmalónica e a homocistinuria são desordens do metabolismo herdados com um amplo espectro de manifestações clínicas que se podem apresentar desde a infância até os adultos maiores. No entanto, com a detecção precose destas doenças, no período neonatal, se teria a oportunidade de melhorar a qualidade de vida dos pacientes afetados.

Tamiz de los errores innatos del metabolismo por espectrometría de masas en tándem: principales biomarcadores / Tandem mass spectrometry as screening for inborn errors of metabolism

The use of tandem mass spectrometry for the diagnosis of inborn errors of metabolism has the potential to expand the newborn screening panel to include a vast number of diseases. This technology allows the detection, in the same spot of dried blood on filter paper and during one single analytical run, of different metabolic diseases. Tandem mass spectrometry is rapidly replacing the classical screening techniques approach of one-metabolite detected per analysis per disease by its ability of simultaneous quantification of several metabolites as markers of many diseases, such as acylcarnitines and amino acids. It is clear that a single metabolite can be a biomarker for several diseases, so the multiplex approach of using tandem mass spectrometry enhances, on average, the sensitivity and specificity of the screening. However, there are differences for particular metabolites and the diseases they detect within the same method. Disorders such as the tyrosinemias and among the organic acidemias, the methylmalonic acidemias, have a substantially higher false-positive rate than other more common metabolic diseases such as medium-chain acyl-CoA dehydrogenase deficiency and phenylketonuria. Before introducing this technology into routine newborn screening programs it is necessary to consider the frequency of each disease, as well as the response to early treatment or variables related to the collection of the sample.

MR study of the brain in patients with tetrahydrobiopterin deficiency / 中华放射学杂志

Objective To observe the brain abnormalities of the white matter and myelination in patients with BH4 deficiency using MRI examination, and to further estimate the effect of treatment. Methods Eleven patients with BH4 deficiency aged 17 weeks to 4 years were observed, including 9 cases who were detected by newborn screening program. Although those patients were treated with low phenylalanine diet, and the blood phenylalanine 1evels maintained to 120-240 ?mol/L, the patients presented progressive hypotonia, convulsion, and mental retardation. All cases were diagnosed as BH4 deficiency by analysis of urinary pterins profile, BH4 loading test, and determination of dihydropteridine reductase in RBC. The patients received MRI examination using a 0.5 T MR system. Results Delayed myelination was found in 11 cases (100%) in frontal lobe, 8 cases (72.2%) in occipital lobe, 4 cases (36.3%) in temporal lobe, and 3 cases (27.3%) in parietal lobe. Delayed myelination of corpus callosum could be found in 6 cases (54.5%). There were abnormal diffuse high signals in the white matter on T_2WI in all cases. Conclusion Patients with BH4 deficiency demonstrate a high occurrence of brain abnormalities in the white matter. Those abnormalities are related not only with hyperphenylalaninemia, but also due to the decreased synthesis of neurotransmitters, such as L-Dopa and 5-HTP, all of these could be the reasons of adverse effect of the development of white matter.