Clinical Application of Liquid Chromatography Tandem Mass Spectrometry Using Dried Blood Spot as a More Rapid Method for Determination of Methylmalonic Acid, Propionylcarnitine, and Total Homocysteine

Nobuyuki Ishige,Mitsuru Kubota,Hiroyuki Iijima

doi:10.1590/2326-4594-jiems-2019-0005

Abstract

Abstract Methylmalonic acidemia (MMA) should be diagnosed in early infancy and receive appropriate management promptly after the diagnosis to prevent severe complications leading to death. At present, a newborn screening (NBS) method using tandem mass spectrometry (MS/MS) identifies suspected patients with MMA by elevated propionylcarnitine. In addition, a liquid chromatography tandem mass spectrometry (LC/MS/MS) method using dried blood spot is effective to detect some metabolites as a second-tier test, and reduces the false-positive rate in NBS. However, these tests were only used in screening, and not applied as an examination for evaluating treatment. Herein, we describe a 57-day-old girl with MMA under treatment with cobalamin who had elevated urinary methylmalonic acid levels. We applied the LC/MS/MS method with a separation column to evaluate her cobalamin responsiveness, and discovered an insufficient cobalamin dose earlier than would have been possible using other methods. Based on the current data, this method seems to be applicable for the follow-up of the treatment of MMA patients. However, this should be confirmed with more experience with a larger number of cases and a wider spectrum of disorders.

Highlights

Methylmalonic acidemia (MMA) is a relatively common autosomal recessive inherited disorder caused by a deficiency of methylmalonyl-CoA mutase (MCM) or its cofactor adenosylcobalamin
LC/method using tandem mass spectrometry (MS/MS) analysis was performed by a Nexera HPLC system, coupled with an LCMS-8050 (Shimadzu Corporation, Kyoto, Japan) for the second-tier test, total homocysteine (tHcy) and methylmalonic acid analysis on dried blood spot (DBS)
The results indicated that C3, C3/C2, and methylmalonic acid levels were decreased on DBS, tHcy was stable at the normal value

Summary

Introduction

Methylmalonic acidemia (MMA) is a relatively common autosomal recessive inherited disorder caused by a deficiency of methylmalonyl-CoA mutase (MCM) or its cofactor adenosylcobalamin. Methylmalonyl-CoA apoenzyme deficiencies are subdivided into two subgroups, i.e., mut– defect with some residual activity in the presence of high concentrations of adenosylcobalamin and mut0 defect with undetectable activity.[1] Patients with MMA display elevation of levels of propionylcarnitine (C3), methylmalonic acid, methylcitric acid, and 3-hydroxypropionic acid. These metabolites are derived from the propionate pathway, namely, isoleucine, valine, threonine, methionine, odd-chain fatty acids, and cholesterol metabolism.[2] the clinical presentation of patients with MMA is variable, the principal symptoms are vomiting, metabolic acidosis, hyperammonemia, and encephalopathy that could cause death. MMA patients with neonatal onset usually have a severe clinical course.[1,3,4] Even under appropriate metabolic management, patients with MMA can experience metabolic attacks and multisystemic disorders, including progressive renal disease,[3,4] cardiomyopathy,[5]

Methods

Results

Conclusion