ACP5 Gene

The ACP5 gene (ACP5 stands for "Acid Phosphatase 5, Tartrate Resistant") is a protein-coding gene located on chromosome 19p13.2. The ACP5 gene encodes an iron-containing glycoprotein that catalyzes the conversion of orthophosphoric acid monoesters to alcohol and orthophosphate. It is the most basic of the acid phosphatases and the only form that is not inhibited by L(+) tartrate.

Tartrate-resistant acid phosphatase (TRAP): It is a member of the ubiquitously expressed enzyme family of acid phosphatases. It is involved in the dephosphorylation of osteopontin/bone sialoprotein. TRAP is localized intracellularly in the lysosomal compartment. Furthermore, TRAP is also known to be secreted by some cell types, particularly osteoclasts. Intracellular iron content, among other factors, is also involved in the regulation of the enzyme.

Almost 30 years ago, TRAP became known in hematology as a cytochemical marker enzyme of hairy cell leukemia . Physiologically, TRAP is primarily a cytochemical marker of macrophages, osteoclasts, and dendritic cells (Lamp EC et al. 2000).

Phosphatase expression appears to be elevated in certain pathological conditions such as Gaucher's disease, Hodgkin's disease, hairy cell leukemia.

Diseases associated with ACP5 include:

• Spondyloenchondrodysplasia With Immune Dysregulation (SPENCDI; OMIM: 607944)

and

• Hairy Cell Leukemia (chronic lymphocytic leukemia caused by excessive production of B cells that appear microscopically hairy).

1. Lamp EC et al (2000) Biology of tartrate-resistant acid phosphatase. Leuk Lymphoma. 39:477-484.
2. Menger H et al (1989) Spondyloenchondrodysplasia. J Med Genet 26: 93-99.
3. Ramesh J et al (2020) Characterization of ACP5 missense mutations encoding tartrate-resistant acid phosphatase associated with spondyloenchondrodysplasia. PLoS One 15:e0230052.