Name short: HMG

Name long: 3-Hydroxy 3-methyl glutaric aciduria

Description: 3-Hydroxy-3-methylglutaryl-CoA lyase deficiency is a rare autosomal recessive disorder with the cardinal manifestations of metabolic acidosis without ketonuria, hypoglycemia, and a characteristic pattern of elevated urinary organic acid metabolites, which include 3-hydroxy-3-methylglutaric, 3-methylglutaric, and 3-hydroxyisovaleric acids. Urinary levels of 3-methylcrotonylglycine may be increased. Dicarboxylic aciduria, hepatomegaly, and hyperammonemia may also be observed. Presenting clinical signs include irritability, lethargy, coma, and vomiting

Incidence in the US 2001-2010: 16 in 24.5 million screens (0.7 cases per million).

Implicated genes:
3-hydroxy-3-methylglutaryl-Coenzyme A lyase, HMGCL


Variants in HMGCL (see gnomAD page):
total variable positions: 329
rare variants: 0
common variants: 0
Allele frequency of rare (<0.001) variants and the implied number of homozygotes and compound heterozygotes, per million births (under the naive assumption that gnomAD captures all variants present in the human population; PSC = premature stop codon):

Population All rare variants Rare, resulting in PSC Rare, not intronic and not silent Known disease related All presumably detrimental
all 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0
afr 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0
amr 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0
asj 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0
eas 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0
fin 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0
nfe 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0
oth 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0
sas 0 => 0 0 => 0 0 => 0 0 => 0 0 => 0


Expected number of homozygotes/compound heterozygotes in a demographic profile close to the US, using all known (as in, listed in gnomAD) rare nontrivial variants as causative variants: 0.

Expected number of homozygotes/compound heterozygotes in a demographic profile close to the US, using all presumably harmful variants as causative variants: 0.

Enzyme structure. Representative chain shown as white cartoon, with positions of known mutations shown as red sticks. Blue: physiological ions. Pink: substrates and cofactors.



Total estimated number of casses per million (all presumably harmful variants): 0.

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