*3.1.5. ALDH7A1*

ALDH7A1 is a homotetramer that's expressed in a large number of tissues; in rat heart, liver and kidney, increased levels of ALDH7A1 are noted, whereas in black seabream fish (sbALDH7A1), ALDH7A1 is significantly formed in the liver and the kidney, excluding the heart. In human fetal tissues, ALDH7A1 has been encountered at elevated levels in the cochlea, eye, ovary, heart and kidney. In contrast, balanced levels are detected in the liver, spleen, muscle, lung and brain.

Human ALDH7A1's primary role happens in the pipecolic acid pathway of lysine catabolism, in which it catalyzes the oxidation reaction of alpha-aminoadipic semialdehyde (AASA) (*K*m180 μM) to alpha-aminoadipate. *ALDH7A1* mutations form the molecular basis for pyridoxine-dependent epilepsy (PDE), an autosomal recessive disorder characterized by the aggression of tenacious seizures during infancy and early childhood and are avoidable by daily use of high-dose pyridoxine (Vitamin B6) supplementation.

Remarkably, ADH7A1 expression in the cochlea of the ear, the region dependent on the healthy upkeep of internal hydrostatic pressure, clarifies that mammalian ALDH7A1 might have an accomplishable function in osmotic regulation and in hearing disorders. However, no connection has been revealed yet, including patients with the inner-ear disorder Ménière's disease, which effects hearing and balance.

ALDH7A1 is notably and differentially expressed within the first and second meiotic stages of porcine oocyte development. Screening of the promoter region *sbALDH7A1* has discovered *cis*-elements linked with cell cycle regulation (Marchitti*, et al.*, 2008).
