Novel mutations in ETFDH gene in Chinese patients with riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency.
BACKGROUND
Multiple acyl-CoA dehydrogenase deficiency (MADD, OMIM 231680) or glutaric aciduria type II (GAII) is an inherited autosomal recessive disease affecting fatty acid, amino acid and choline metabolism, due to mutations in one of three genes namely, electron transfer flavoprotein alpha-subunit, ETFA (OMIM 608053), electron transfer flavoprotein beta-subunit, ETFB (OMIM 130410) and electron transfer flavoprotein dehydrogenase, ETFDH (OMIM 231675). Some MADD patients are responsive to riboflavin treatment with an excellent prognosis. Recently, mutations in ETFDH were found to be responsible for all riboflavin-responsive MADD patients. In this study, we present the clinical features and molecular studies of 2 Chinese families with riboflavin-responsive MADD.


METHODS
Genomic DNA was extracted from peripheral blood samples or skin fibroblast cultures from the patients and normal controls. The thirteen exons of ETFDH were amplified by PCR. PCR products were sequenced in both forward and reverse directions. To rule out mutations in other genes, phenotype segregation was studied in the families by microsatellite markers in the proximity of the 3 genes, ETFA, ETFB and ETFDH.


RESULTS
Four novel mutations in ETFDH were detected in the 2 families. In family 1, a frame shift mutation, c.1355delG which introduced a premature-termination codon (PTC), I454X in exon 11 of ETFDH was found. Another mutation was a c.250G>A transition in exon 3 of ETFDH, A84T. In family 2, two novel missense mutations were identified, P137S, in exon 4 and G467R in exon 11. No carrier of these four mutations was identified from about 150 alleles of healthy Chinese control subjects.


CONCLUSIONS
Four novel mutations (3 missenses and 1 deletion) in ETFDH were found in Chinese families that presented with riboflavin-responsive MADD, which further expands the list of mutations found in patients with riboflavin-responsive MADD. Furthermore, we illustrated the utility of phenotype-genotype segregation in MADD families to prioritize genes for sequencing or to rule out the presence of disease causing mutation in other genes in MADD and other diseases caused by multiple genes.
Law
Lap-Kay
LK
Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong.
Tang
Nelson L S
NL
Hui
Joannie
J
Fung
Simon L M
SL
Ruiter
Jos
J
Wanders
Ronald J A
RJ
Fok
Tai-Fai
TF
Lam
Christopher W K
CW
D002675:Child, Preschool; D002681:China; D004252:DNA Mutational Analysis; D044927:Electron-Transferring Flavoproteins / Q000187:drug effects / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D016368:Frameshift Mutation / Q000235:genetics; D006801:Humans; D007223:Infant; D007506:Iron-Sulfur Proteins / Q000187:drug effects / Q000235:genetics*; D018895:Microsatellite Repeats / Q000235:genetics; D054069:Multiple Acyl Coenzyme A Dehydrogenase Deficiency / Q000188:drug therapy* / Q000235:genetics*; D020125:Mutation, Missense / Q000235:genetics; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000187:drug effects / Q000235:genetics*; D012256:Riboflavin / Q000627:therapeutic use; D055815:Young Adult
D044927:Electron-Transferring Flavoproteins; D007506:Iron-Sulfur Proteins; D000587:Oxidoreductases Acting on CH-NH Group Donors; C023120:electron-transferring-flavoprotein dehydrogenase; D012256:Riboflavin