Pediatria Clínica: Acesso Aberto
Acesso livre

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A Rare Case of Malonyl-CoA Decarboxylase Deficiency with Novel Mutations in the MLYCD Gene in Two Indian Patients and Literature Review

Radha Rama Devi*, Nalinikanth Panigrahi

Malonyl-CoA decarboxylase deficiency causing isolated malonic aciduria is a rare inborn error of metabolism with heterogeneous phenotypic manifestations. The disease can be diagnosed in new-born screening. Early treatment prevents development of cardiomyopathy and intellectual disability. Tandem Mass Spectrometer (TMS) and urine Gas Chromatography Mass Spectrometry (GC-MS) and whole exome sequencing confirms the diagnosis.

Results: Two patients from unrelated families were diagnosed with elevated C3DC acyl carnitine and increases excretion of malonic acid in the urine. The concentration of malonic acid in the urine was very high in case 1 as the test was done during acute crisis (423-fold elevation). Case 2 had 11-fold elevation (not in decompensation). No methyl malonic acid was detected in both the cases. Both the patients harbored novel mutations in the MLYCD gene. Case1 was homozygous c.C928T (p.Arg 310Ter) is stop gain mutation and case 2 was a compound heterozygote missense c.G1153A (p.Val385Met) and missense/exonic splicing c.G1175A (p.Arg392Gln) mutation in Exon 5.

Conclusion: Two additional cases of malonic aciduria were reported adding to the 54 earlier reported cases. The disease is extremely rare, mainly characterized by hypoglycemia and metabolic acidosis cardiomyopathy is a later manifestation. Newborn screening can identify the presence of elevated C3DC. There are no recommendations regarding the appropriate treatment regimen. Both the patients have novel genetic variants.