39. Sàng lọc Methylmalonic Acidemia và Propionic Acidemia bằng phương pháp khối phổ đôi: Hồi cứu loạt ca bệnh

Abstract

Methylmalonic Acidemia (MMA) is a group of autosomal recessive genetic disorders, typically involving defects in the conversion of methylmalonyl-CoA to succinyl-CoA, characterized by the accumulation of methylmalonic acid. Meanwhile, Propionic Acidemia (PPA) is an autosomal recessive disorder related to the conversion of propionyl-CoA to methylmalonyl-CoA by the enzyme propionyl-CoA carboxylase in the mitochondria. Due to nonspecific clinical manifestations, biochemical testing plays a crucial role in screening and diagnosing MMA and PPA. A retrospective study, describing a series of cases, was conducted to evaluate the result of screening for MMA and PPA in high-risk patients. Quantification of acylcarnitines in dried blood spots using tandem mass spectrometry (MS/MS) and analysis of organic acids in urine by gas chromatography-mass spectrometry (GC/MS) were applied for screening and diagnosis in 6 MMA patients and 7 PPA patients (from 9/2018 to 12/2021) at the National Children’s Hospital. Screening results by MS/MS for 6 MMA patients showed 4/6 had elevated C3, 3/6 had decreased C0, and all 6/6 had increased C3/C2 ratio. Screening results for metabolic disorders by MS/MS in 7 PPA patients showed all had elevated C3 and C3/C2 ratio. Urinary organic acid testing showed elevated methylmalonic acid, allowing differentiation between MMA and PPA since methylmalonic acid does not increase in PPA.