This report describes glycerol kinase deficiency (GKD); GKD exhibits X-linked recessive inheritance. The human gene implicated in this disease is GK, which encodes glycerol kinase, a key enzyme in the regulation of glycerol uptake and metabolism. GK is also associated with Xp21 contiguous gene deletion syndrome (MIM:300679), in which it is one of three deleted genes. There are three high-scoring fly orthologs, Gk1, Gk2, and CG8298, for which RNAi targeting constructs and alleles caused by insertional mutagenesis have been generated.
A UAS construct of a wild-type human Hsap\GK gene has been introduced into flies, but has not been characterized.
Loss of function effect by RNAi against either Dmel\Gk1 or Dmel\Gk2 results in larval lethality (in some lines) or an adult conditional phenotype: adults have a reduced lifespan when raised on a glycerol food source, but not when raised on a sucrose food source (glycerol hypersensitivity). Genetic and physical interactions have been described for both Dmel\Gk1 and Dmel\Gk2; see below and in the Gk1 and Gk2 gene reports.
[updated Sep. 2018 by FlyBase; FBrf0222196]
[GLYCEROL KINASE DEFICIENCY; GKD](https://omim.org/entry/307030)
[GLYCEROL KINASE; GK](https://omim.org/entry/300474)
Glycerol kinase deficiency (GKD) can be either symptomatic with episodic metabolic and central nervous system decompensation or asymptomatic with hyperglycerolemia and glyceroluria only (Dipple, et al., 2001, pubmed:11479736). Isolated GK deficiency, in which the GK gene alone is affected, results in the juvenile and adult onset forms; the adult form has no symptoms and is often detected fortuitously (Francke, et al., 2007, pubmed:2883886). The infantile form, also referred to as GK complex, is part of the Xp21 contiguous gene deletion syndrome (MIM:300679), and is associated with severe developmental delay. [From MIM:307030 and MIM:300474, 2016.06.20]
Glycerol kinase deficiency (GKD) is caused by mutation in the gene encoding glycerol kinase (GK).
The infantile form of GK deficiency, or the 'GK complex,' results from the Xp21 contiguous gene deletion syndrome (MIM:300679) with congenital adrenal hypoplasia (MIM:300200) and/or Duchenne muscular dystrophy (DMD; MIM:310200), whereas the juvenile and adult forms have isolated GK deficiency (Walker et al., 1996, pubmed:8651297]). [From MIM:307030, 2016.06.20]
The GK gene encodes glycerol kinase, a protein that belongs to the FGGY kinase family. This protein is a key enzyme in the regulation of glycerol uptake and metabolism. It catalyzes the phosphorylation of glycerol by ATP, yielding ADP and glycerol-3-phosphate. [provided by RefSeq, Mar 2011]
Glycerol kinase (GK) catalyzes the phosphorylation of glycerol by ATP, yielding ADP and glycerol-3-phosphate. [From MIM:300474, 2016.06.16]
Many to many: 2 human to 3 Drosophila.
Ortholog of human GK and GK2 (3 Drosophila to 2 human). Dmel\Gk1 shares 53% identity and 70% similarity with human GK, and 53% identity and 69% similarity with human GK2.
Ortholog of human GK and GK2 (3 Drosophila to 2 human). Dmel\Gk2 shares 47% identity and 68% similarity with human GK, and 47% identity and 67% similarity with human GK2.
