SLC3A1 gene

solute carrier family 3 member 1

The SLC3A1 gene provides instructions for producing one part (subunit) of a protein made primarily in the kidneys. This subunit joins with another protein subunit, produced from the SLC7A9 gene, to form a transporter protein complex. During the process of urine formation in the kidneys, this protein complex absorbs particular protein building blocks (amino acids) back into the blood. In particular, the amino acids cystine, ornithine, arginine, and lysine are absorbed back into the blood through this mechanism.

More than 120 mutations in the SLC3A1 gene have been found to cause cystinuria. Many of these mutations alter a single DNA building block (nucleotide) or insert or delete a small number of nucleotides in the SLC3A1 gene. These changes lead to an abnormally functioning transporter protein complex, which causes certain amino acids to become concentrated in the urine. Cystine is the only amino acid that forms crystals and stones in the bladder or kidneys, leading to the signs and symptoms of cystinuria.

Some people with cystinuria have large DNA deletions that remove not only the SLC3A1 gene but one or more neighboring genes. Individuals with these large DNA deletions have the signs and symptoms of cystinuria, but they can also have other features.

Deletions of the SLC3A1 gene and the neighboring PREPL gene cause hypotonia-cystinuria syndrome. In addition to cystinuria, people with this condition have low muscle tone (hypotonia) and poor feeding, which usually improves by early childhood. They may also have droopy eyelids (ptosis), an elongated head (dolichocephaly), and mild intellectual disability. Most people with this condition have short stature.

Deletions of the SLC3A1 gene, the PREPL gene, and the C2orf34 gene cause atypical hypotonia-cystinuria syndrome. In addition to the symptoms of hypotonia-cystinuria syndrome, individuals with the atypical form have mild to moderate delay in the development of mental and motor skills (psychomotor delay).

Deletions of the SLC3A1 gene, the PREPL gene, the C2orf34 gene, and the PPM1B gene cause 2p21 deletion syndrome. In addition to all the symptoms of the previous syndromes, individuals with 2p21 deletion syndrome have seizures soon after birth, moderate to severe psychomotor delay, and impairments in the process from which cells derive much of their energy (oxidative phosphorylation). People with this condition typically have a characteristic facial appearance with a prominent forehead, long eyelashes, a flat nasal bridge, and abnormally turned ears.

Cytogenetic Location: 2p16.3, which is the short (p) arm of chromosome 2 at position 16.3

Molecular Location: base pairs 44,275,458 to 44,320,824 on chromosome 2 (Homo sapiens Annotation Release 108, GRCh38.p7) (NCBI)

Cytogenetic Location: 2p16.3, which is the short (p) arm of chromosome 2 at position 16.3
  • amino acid transporter 1
  • ATR1
  • CSNU1
  • D2H
  • NBAT
  • RBAT
  • SLC31_HUMAN
  • solute carrier family 3 (amino acid transporter heavy chain), member 1
  • solute carrier family 3 (cystine, dibasic and neutral amino acid transporters), member 1
  • solute carrier family 3 (cystine, dibasic and neutral amino acid transporters, activator of cystine, dibasic and neutral amino acid transport), member 1
  • solute carrier family 3, member 1