A novel missense mutation in the SLC6A19 gene in a Chinese family with Hartnup disorder.

BACKGROUND: Hartnup disease is a rare autosomal-recessive abnormality of renal and gastrointestinal neutral amino acid transport associated with neurologic, psychiatric, and dermatologic symptoms. Mutations in the SLC6A19 gene have been proposed to be responsible for the underlying changes in this disorder.

AIM: To investigate a pedigree with Hartnup disorder and to search for the mutation in the SLC6A19 gene in this pedigree.

METHODS: The encoding exons of the SLC6A19 gene were amplified and sequenced from genomic DNA samples. Amino acids were determined in urine samples from the proband and her family members.

RESULTS: The proband and her brother had a homozygous mutation of c.850G > A in the SLC6A19 gene, causing G284R in the transmembrane domain of the SLC6A19 transporter, inherited from their parents who were heterozygous carriers. Their urine samples showed increased values of eight neutral amino acids.

CONCLUSION: We found a novel homozygous mutation of G284R in the transmembrane domain of the SLC6A19 transporter in the proband, with typical dermatologic and neurologic manifestations and increased levels of urinary neutral amino acids.