Table 2.

Molecular genetics of disorders in the BCAA metabolic pathway

Disorder	MIM #	Gene	Locus
	Phenotype/Locus
Maple syrup urine disease
Type Ia	248600, 608348	BCKDHA	19q13.1-13.2
Type Ib	248600, 248611	BCKDHB	6q14.1
Type II	248600, 248610	DBT	1p21.2
?mild variant	615135, 611065	PPM1K	4q22.1
Isovaleric acidemia	243500, 607036	IVD	15q15.1
3-Methylcrotonyl-CoA carboxylase deficiency	210200, 609010	MCCC1	3q27.1
210210, 609014	MCCC2	5q13.2
3-Methylglutaconic aciduria type I	250950, 600529	AUH	9q22.31
3-Methylglutaconic aciduria type II:	302060, 300394	TAZ	Xq28
Barth syndrome
3-Methylglutaconic aciduria type III:	258501, 606580	OPA3	19q13.32
Costeff optic atrophy
3-Methylglutaconic aciduria type IV: “unclassified”	N/A	N/A	N/A
type V	610198, 608977	DNAJC19	3q26.33
type VI: deafness, encephalopathy, Leigh-like syndrome	614739, 614725	SERAC1	6q25.3
type VII: cataracts, neurological involvement and neutropenia	616271, 616254	CLPB	11q13.4
3-Hydroxy-3- methylglutaryl-CoA lyase deficiency	246450, 613898	HMGCL	1p36.11
Methylbutyryl-CoA dehydrogenase deficiency	610006, 600301	ACADSB	10q26.13
Mitochondrial acetoacetyl-CoA thiolase deficiency	203750, 607809	ACAT1	11q22.3
Isobutyryl-CoA dehydrogenase deficiency	611283, 604773	ACAD8	11q25
3-Hydroxyisobutyryl- CoA deacylase deficiency	250620, 610690	HIBCH	2q32.2
3-Hydroxyisobutyric aciduria	N/A	N/A	N/A
Methylmalonic semialdehyde dehydrogenase deficiency	614105, 603178	ALDH6A1	14q24.3
Propionic acidemia	606054, 232000	PCCA	13q32.3
606054, 232050	PCCB	3q22.3
Methylmalonic acidemia, isolated
Mut subtype	251000, 609058	MUT	6p12.2
Cobalamin A	251100, 607481	MMAA	4q31.21
Cobalamin B	251110, 607568	MMAB	12q24.11
Cobalamin D	277410, 611935	C2orf25	2q32.2