Development of a new enzymatic diagnosis method for very-long-chain Acyl-CoA dehydrogenase deficiency by detecting 2-hexadecenoyl-CoA production and its application in tandem mass spectrometry-based selective screening and newborn screening in Japan.
The introduction of tandem mass spectrometry (MS/MS) has made it possible to screen for very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. To confirm the diagnosis in cases with an abnormal profile of blood acylcarnitines, we developed a new enzymatic assay method for determining dehydrogenase activity toward palmitoyl-CoA (C16:0) in lymphocytes. Using this method, the production of 2-hexadecenoyl-CoA (C16:1) by crude cell lysates can be directly quantified using high performance liquid chromatography (HPLC). We applied the assay to 7 myopathic patients, 7 hypoglycemic patients, and 2 presymptomatic newborns with elevated levels of tetradecenoylcarnitine (C14:1 AC) in blood, and found impaired VLCAD activity in all of the 7 myopathic patients and both of the 2 newborns. All of the 7 hypoglycemic patients had normal level of the enzyme activity. Results of the ACADVL gene analysis were in consistent with the enzymatic diagnosis. These results suggest that MS/MS-based screening for VLCAD deficiency using blood C14:1 AC as the indicator may show a considerably high false-positive rate in selective screening of symptomatic patients. Our practical enzymatic assay can be a useful test for the accurate diagnosis of VLCAD deficiency cases screened by MS/MS.
Tajima
Go
G
Department of Pediatrics, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima 734-8551, Japan. acadugo@mac.com
Sakura
Nobuo
N
Shirao
Kenichiro
K
Okada
Satoshi
S
Tsumura
Miyuki
M
Nishimura
Yutaka
Y
Ono
Hiroaki
H
Hasegawa
Yuki
Y
Hata
Ikue
I
Naito
Etsuo
E
Yamaguchi
Seiji
S
Shigematsu
Yosuke
Y
Kobayashi
Masao
M
D000214:Acyl Coenzyme A / Q000378:metabolism*; D044942:Acyl-CoA Dehydrogenase, Long-Chain / Q000172:deficiency* / Q000235:genetics; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007564:Japan; D052439:Lipid Metabolism Disorders / Q000175:diagnosis* / Q000235:genetics; D008297:Male; D015997:Neonatal Screening / Q000379:methods*; D010171:Palmitoyl Coenzyme A / Q000378:metabolism; D053719:Tandem Mass Spectrometry / Q000379:methods*; D055815:Young Adult
C117110:2-hexadecenoyl-coenzyme A; D000214:Acyl Coenzyme A; D010171:Palmitoyl Coenzyme A; D044942:Acyl-CoA Dehydrogenase, Long-Chain