Hartnup disease

Epidemiology

rare: 1 in 15,000 newborns

Pathology

• reduced renal tubular resorption mono-amino & carboxylic- amino acids (renal function otherwise normal)
• aberrant intestinal transport of mono-amino & carboxylic- amino acids
• inadequate tryptophan availability limits nicotinamide synthesis; secondary pellagra

Genetics

• autosomal recessive
• caused by mutations in the SLC6A19 gene

Clinical manifestations

• pellagra-like rash (after exposure to sunlight)
• episodic cerebellar ataxia
• delirium
• malnutrition may occur
• disorder often improves with age
• clinical variability, may be asymptomatic

Laboratory

• neutral aminoaciduria
• hypouricemia

Management

• nicotinamide 40-200 mg PO QD
• high protein diet
• prognosis is good

More general terms

• genetic disease of the kidney
• genetic syndrome (multisystem disorder)

Additional terms

• solute carrier family 6 member 10 (SLC6A19, Na+ dependent neutral amino acid transporter B0, system B0 neutral amino acid transporter, B0AT1)

Database

• OMIM: https://mirror.omim.org/entry/234500