GroupPresentingHPOs: HP:0001987, HP:0001942, HP:0003128, HP:0002912 (hyperammonemia, metabolic acidosis, lactic acidosis, methylmalonic acidemia)
HPOsFreeText: elevated blood levels of propionylcarnitine (C3) (median 13.56 umol/L), and elevated C3 to acetylcarnitine (C2) ratio (median 0.85). elevated urine methylmalonate levels (median 598.96 mmol/mol creatinine). 28/73.7% displayed recurrent vomiting (HP:0002572). 28/73.7% displayed disturbances of consciousness (HP:0004372). 23/60.5% displayed feeding difficulties in infancy (HP:0008872), 20/52.6% displayed respiratory distress (HP:0002098), 20/52.6% displayed failure to thrive (HP:0001508), 20/52.6% displayed dystonia (HP:0001332), 14/36.8% displayed mental retardation, 12/31.6% displayed convulsions.
GroupNotHPOs: normal plasma total homocysteine
NotHPOsFreeText:
NumberMales: 27
NumberFemales: 16
CountryOrigin: China
Ethnicity: Chinese
AgeRange: 33d- 10.3 y at last follow up
TotalNumber 43
FamilyInfo: 43
NoFamily: 0
GroupAddInfo: 9 identified by NBS, 34 recruited after being suspected of inherited metabolism disorders. 42 families from 14 provinces of the Mainland of China. 8 died during acute metabolic crisis, 7 lost to follow up, 28 alive at end of study.
Group (Level 2)
VariantCount: 43 (35 had two mutant alleles)
NonVariant: 0
OtherVariant: 0
GroupPreviousTesting: tandem mass spectrometry for blood levels, gas chromatography-mass spectrometry for urine,
GroupMethod1: PCR
GroupGenotypingMethod: genomic DNA extracted from peripheral blood leukocytes from patients and their parents. Exonic and flanking intronic regions of the MUT gene were amplified through PCR. PCR products were sequenced directly using forward and reverse primers on ABI 3700 sequencer. Mutation analysis using MUT reference NM_000255.3. Nucleotide numbering reflects cDNA numbering (initiation codon= codon1). All detected mutations were confirmed in the patients' parents. Novel variants were screened in 100 alleles from 50 control children. Novel variants were considered pathogenic when predicted to be deleterious by two algorithms.