Hartnup syndrome E72.02

Autosomal-recessive inherited disorder of tubular and enteral absorption of certain amino acids, especially tryptophane with cerebellar symptoms, light dermatosis and aminoaciduria.

One of the most common hereditary disorders of amino acid transport. Prevalence: about 1/40.000 births.

Autosomal recessive mutations of the "hartnup disorder" gene (HND gene; gene locus: 5p15) and consecutive defects in the transport of monoaminomonocarboxylic acids in the small intestine and kidneys with reduced renal absorption of neutral amino acids.

• Skin symptoms: Seasonal pellagroid skin changes with redness, swelling and itching, poikiloderma.
• Extracutaneous manifestations: cerebellar ataxia, psychic changes.

Nicotinamide (e.g. Nicotinamide 200 Jenapharm) in high doses (50-300 mg/day). Protein-rich diet. Avoid greater exposure to the sun, sun protection. Monoamine oxidase inhibitors are contraindicated.

The name Hartnup comes from the family where the disease was first diagnosed.

1. Baron DN, Dent CE, Harris H, Hart EW, Jepson JB (1956) Hereditary pellagra-like skin rash with temporary cerebellar ataxia, constant renal amino-aciduria and other bizarre biochemical features. Lancet II: 421-433
2. Potter SJ et al (2002) Hartnup disorder: polymorphisms identified in the neutral amino acid transporter SLC1A5. J Inherite Metab Dis 25: 437-448