BabyScreen+ newborn screening

Gene: MUT

Green List (high evidence)

Well established gene-disease association.

Isolated methylmalonic aciduria is found in patients with mutations in the MUT gene causing partial, mut(-), or complete, mut(0), enzyme deficiency. Variable severity and age of onset:

• Infantile completely deficient (mut0) or non-B12-responsive (clbB) is the most common phenotype and presents during infancy. Infants are normal at birth, but develop lethargy, vomiting, and dehydration within the first few months of life. They may also exhibit hepatomegaly, hypotonia, encephalopathy, metabolic acidosis, ketosis and ketonuria, hyperammonemia, and hyperglycemia.

• Partially deficient (mut-) or B12-responsive (cblA, cblD, rarely cblB) is an intermediate phenotype that can occur in the first few months or years of life. Symptoms include feeding problems, failure to thrive, hypotonia, and developmental delay. Some have protein aversion and vomiting, and lethargy after protein intake.

Non-genetic confirmatory tests: serum amino acids, urine organic acids

Treatment: cobalamin, N-carbamylglutamate, carnitine, diet, liver transplant

Created: 2 Oct 2022, 9:15 a.m. | Last Modified: 2 Oct 2022, 9:15 a.m.

Panel Version: 0.270

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Methylmalonic aciduria, mut(0) type, MIM# 251000

Green List (high evidence)

is on the current VCGS newborn screening panel

Created: 26 Sep 2022, 2:19 a.m. | Last Modified: 26 Sep 2022, 2:19 a.m.

Panel Version: 0.199

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal