A Rare Case of Malonic Aciduria Diagnosed by Newborn Screening in Qatar

Malonic aciduria is a rare autosomal recessive organic acid disorder. With the widespread use of tandem mass spectrometry for analysis of the amino acid/acylcarnitine profile on dried blood spots for newborn screening (NBS), this condition can be readily diagnosed and can be included in the organic acid screen in NBS programs. In Qatar, we report the first case of an asymptomatic baby screened and diagnosed with malonic aciduria through NBS. This patient has a genetic variant of malonyl-CoA decarboxylase that has not been previously reported in the literature. This condition should be differentiated from a similar disorder, combined malonic and methylmalonic aciduria. The clinical phenotype of malonic aciduria is variable and the pathophysiology is not fully understood. There is no established guidance or recommendations regarding the appropriate treatment regimen, dietary therapy or regular follow-up of these patients. Most available evidence for treatment is based on a single study or case report.