Disease relevance of PHKA1

• Muscle glycogenosis with low phosphorylase kinase activity: mutations in PHKA1, PHKG1 or six other candidate genes explain only a minority of cases [1].
• Myopathy and phosphorylase kinase deficiency caused by a mutation in the PHKA1 gene [2].

High impact information on PHKA1

• In contrast to the muscle isoform gene, PHKA1, the gene of this additional isoform, PHKA2, is predominantly expressed in liver and other nonmuscle tissues [3].
• Assignment of human genes for phosphorylase kinase subunits alpha (PHKA) to Xq12-q13 and beta (PHKB) to 16q12-q13 [4].
• Only in one male patient did we find a PHKA1 missense mutation (D299V) that explains the enzyme deficiency [1].
• In addition to mapping of the brain-specific gene (NAP1L2) and the phosphoglyceryl kinase alpha subunit 1 gene (PHKA1) and generation and mapping of a large number of STSs throughout the contig, we have mapped a putative transcriptional regulatory protein (HDACL1), and 35 ESTs [5].
• Dinucleotide repeat polymorphism within the PHKA1 gene at Xq12-q13 [6].

Biological context of PHKA1

• We recently mapped the muscle alpha-subunit gene (Phka) to the mouse X chromosome in a region syntenic with the proximal long arm of the human X chromosome and containing the human homologue of this gene, PHKA [7].
• We report here the chromosomal localization by in situ hybridization of a liver PHKA gene to the distal region of chromosome Xp [8].
• Regional mapping of a liver alpha-subunit gene of phosphorylase kinase (PHKA) to the distal region of human chromosome Xp [8].
• Our results localize PHKA to the X chromosome at the proximal end of the long arm, near the centromere, and PHKB to the same location on chromosome 5 [9].

References