Fatty Acid Oxidation Defects

Gene: ETFB

Green List (high evidence)

Glutaric aciduria II (GA2) is an autosomal recessively inherited disorder of fatty acid, amino acid, and choline metabolism. It differs from GA I in that multiple acyl-CoA dehydrogenase deficiencies result in large excretion not only of glutaric acid, but also of lactic, ethylmalonic, butyric, isobutyric, 2-methyl-butyric, and isovaleric acids.

The heterogeneous clinical features of MADD fall into 3 classes: a neonatal-onset form with congenital anomalies (type I), a neonatal-onset form without congenital anomalies (type II), and a late-onset form (type III). The neonatal-onset forms are usually fatal and are characterized by severe nonketotic hypoglycemia, metabolic acidosis, multisystem involvement, and excretion of large amounts of fatty acid- and amino acid-derived metabolites. Symptoms and age at presentation of late-onset MADD are highly variable and characterized by recurrent episodes of lethargy, vomiting, hypoglycemia, metabolic acidosis, and hepatomegaly often preceded by metabolic stress. Muscle involvement in the form of pain, weakness, and lipid storage myopathy also occurs. The organic aciduria in those with the late-onset form of MADD is often intermittent and only evident during periods of illness or catabolic stress.

Well established gene-disease association.

Created: 2 Jan 2021, 3:56 a.m. | Last Modified: 2 Jan 2021, 3:56 a.m.

Panel Version: 0.55

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Glutaric acidemia IIB, MIM# 231680