The role of the neutral amino acid transporter B⁰AT1 (SLC6A19) in hartnup disorder and protein nutrition

Hartnup disorder (OMIM 234500) is an autosomal recessive disorder, which was first described in 1956 as an aminoaciduria of neutral amino acids accompanied by a variety of symptoms, such as a photo-sensitive skin-rash and cerebellar ataxia. The disorder is caused by mutations in the neutral amino acid transporter B⁰AT1 (SLC6A19)¹. To date 21 mutations have been identified in more than twenty families. SLC6A19 requires either collectrin or angiotensin-converting enzyme 2 for surface expression in the kidney and intestine, respectively. This ties SLC6A19 together with more complex functions such as blood-pressure control, glomerular structure, and exocytosis.