Abstract: Objective To investigate the clinical and gene mutation characteristics of short chain acyl-CoA dehydrogenase deficiency(SCADD) in Qingdao area. Methods The acylcarnitine levels in the blood of 283104 neonates from newborns screening program were measured by tandem mass spectrometry. The suspected SCADD neonates were diagnosed by retrospective analysis of the urine organic acids and short chain acyl-CoA dehydrogenase (ACADS) gene mutation characteristics. Results Four cases of short chain acyl-CoA dehydrogenase deficiency(SCADD)were diagnosed, with an incidence of 0.0014%(1/70776). There was no obvious abnormality in clinical manifestations. The results showed blood butyl carnitine (C4) levels and the ratios of C4 to acetylcarnitine (C2) and propionyl carnitine (C3) increased. Urinary organic acids were analyzed in 4 cases, all of which ethyl malonate acid was increased [8.41~36.34 mg/g creatinine (reference value 0~6.20mg/g creatinine)], two patients were accompanied by increased lactic acid and one subiect with increased pyruvic acid. A total of 7 mutations were detected in the ACADS gene. Four are known mutations, three are not reported mutations, all of them are missense mutations. The 4 patients were all compound heterozygous mutations: c.1031A>G/c.989G>A；c.1186G>A/c.1195C>T；c.1031A>G/c.445A>T；c.1130C>T/ c.1157G>A。Common mutation was c.1031A>G(25%). The ACADS genotype was not significantly correlated with the concentrations of ethyl malonate acid and C4. Dietary guidance was provided to the SCADD patients. No clinical symptoms and normal physical and intellectual development occurred during the follow-up period. Conclusions The diagnosis of SCADD can be confirmed by the screening of neonatal blood mass spectrometry and gene sequencing. Early diagnosis of neonates without clinical symptoms and the prognosis is good.

Key words: Short chain acyl-CoA dehydrogenase deficiency, Tandem mass spectrometry, Gene mutation