| Objective:The clinical data,genotype,responsiveness to vitamin B12,and prognosis of 77 patients with methylmalonic acidemia were analyzed to guide future clinical work.Methods:Single-center retrospective study Clinical features,laboratory tests,imaging studies,developmental tests,genotypes of 77 patients with methylmalonic acidemia who were admitted to the Second Hospital of Hebei Medical University from January 2009 to January 2019.And the effect of treatment.And compared with simple methylmalonic acidemia and methylmalonic acidemia with homocysteinemia for vitamin B12 loading after treatment with propionylcarnitine(C3),propionylcarnitine/acetylcarnitine(C3/C2),changes in urinary methylmalonic acid,methyl decanoic acid.Results:Of the 77 patients with methylmalonic acidemia,40(51.9%)were male,37(48.1%)were female,25(32.5%)were simple,and 52(67.5%)were homocysteinemia.).Twenty-four(31.2%)newborns were found to have clinical manifestations in 11 cases(14.3%);66 cases(85.7%)had different degrees and different types of clinical manifestations,which were clinically diagnosed cases.The children developed from a few minutes to 10 years after birth.The clinical manifestations included 42 cases of mental retardation and motor development,26 cases of lethargy,25 cases of feeding difficulties,18 cases of anemia,14 cases of vomiting,14 cases of convulsions,and 9 cases of abnormal muscle tone.There were 7 cases of coughing repeatedly,7 cases of hydrocephalus,6 cases of coma,3 cases of diarrhea,4 cases of acidosis,2 cases of thrombocytopenia and 2 cases of optic nerve injury.Some patients have multiple organ damage such as blood,cardiovascular and kidney.The 24 children diagnosed by newborn screening developed better.Of the 77 patients diagnosed,75(97.4%)received treatment,9(24.6%)had normal intelligence and motor development,3(3.9%)died,and 42(54.5%)had residual light to extreme Severe mental dyskinesia.59 patients underwent genetic analysis and obtained genetic diagnosis,including 42 patients(71.2%)with MMAKA and 17 patients(28.8%)with MUT.Among the MMACHC mutations,exon3 C.609 G>A(40.0%),exon1 C.80 A>G(9.4%)and exon4 C.656-658 del AGA(8.2%)were dominant,and MUT mutations were exon3.C.729-730insTT(18.2%)and exon2 C.323 G>A(15.2%)are mostly of two types.Sixteen patients with simple methylmalonic acidemia and 44 children with combined intramuscular injection of vitamin B12 1 mg/day were given for 7 consecutive days.Before and after treatment,blood C3,C3/C2,and urinary methylmalonic acid were compared.Changes in methyl decanoic acid,statistical analysis,the median of each indicator in simple children was 9.43 μmol / L before treatment,0.61,140.50 and 3.35 became 11.85μmol/L,0.69,141.50 and 2.95 after treatment,P>0.05,the difference was not statistically significant.The current data does not support the effective treatment of vitamin B12.The median of each index in the combined children decreased from 6.46μmol/L,0.45,51.65 and 1.12 before treatment to 4.29μmol/L,0.22,17.70 and 0.40 after treatment,P<0.05,the difference was statistically significant.Vitamin B12 is effective for its treatment.Conclusions:1.There are many genotypes in this disease,including MMACHC gene mutation(71.2%)and MUT gene mutation(28.8%).Exon3 C.609 G>A(40.0%)and exon1 C.80 in MMACHC mutation.A>G(9.4%)and exon4 C.656-658 del AGA(8.2%)are mostly three types.Exon3 C.729-730insTT(18.2%)and exon2 C.323 G>A(15.2%)Both types are mostly.2.Clinical phenotypic characteristics of methylmalonic acidemia: The clinical manifestations of this disease are complex and diverse,lacking specificity,and early diagnosis is of great significance.Mental retardation,drowsiness,feeding difficulties,anemia,vomiting,convulsions,and abnormal muscle tone are common first-episode symptoms.3.Reactive characteristics of vitamin B12: children with simple methylmalonic acidemia have poor response to vitamin B12,the current data does not support the effective treatment of vitamin B12;methylmalonic acidemia combined with homocysteineemia The child responds well to vitamin B12 and is effective.The response to vitamin B12 helps to distinguish whether methylmalonic acidemia is associated with homocysteinemia.4.The prognosis of patients with methylmalonic acidemia is closely related to the clinical type and the onset of the disease.Patients with effective vitamin B12 have a good prognosis,and patients with ineffective vitamin B12 have a poor prognosis.The earlier the onset age,the worse the prognosis.Early treatment can help improve prognosis. |
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