Cystinuria (Cystinuria) - Genes SLC3A1 or SLC7A9

Cystinuria is a disorder characterized by the accumulation of the amino acid cystine in the kidneys and bladder. When the kidneys filter blood, cystine normally reabsorbed into the bloodstream. People with cystinuria can not properly reabsorb cystine, so that the amino acid builds up in your urine. By focusing cystine, it crystallized. Larger crystals become stones that can be placed in the kidneys or bladder. Sometimes, the cystine crystals combine with calcium to form molecules large stones. These crystals and stones can create obstructions in the urinary tract and reduce the ability of the kidneys to eliminate waste through urine. The calculations also offer places where bacteria can settle and cause urinary tract infections.

Cystinuria is due to alterations in the SLC7A9 gene sequence of SLC3A1 and, located on the long arm of chromosome 19 (19q13.1), encoding two subunits of a protein complex found primarily in the kidneys. Typically this protein complex controlling the reabsorption of certain amino acids, including cystine, from the glomerular filtrate into the blood. Mutations in the gene SLC3A1 SLC7A9 gene or disrupt the ability of the complex of these proteins to reabsorb amino acids, mainly cystine, ornithine, arginine and lysine. Amino acids not reabsorbed are concentrated in the urine, forming crystals typical cystinuria, while other amino acids which are not reabsorbed by the complex of these proteins do not give rise to crystals when they accumulate in urine.

We found over 120 mutations in the SLC3A1 gene in people with cystinuria. Many of these mutations change a nucleotide, or insert or remove a small number of nucleotides in the gene. These changes result in the synthesis of a transport protein abnormal operation causing no certain amino acids in the urine concentrate properly reabsorbed. Some people with cystinuria have large deletions of DNA that removes not only the gene SLC3A1 but one or more genes neighbors. Individuals with these large DNA deletions have signs and symptoms of cystinuria, but may also have other diseases.

Meanwhile, at least 95 mutations in the SLC7A9 gene have been identified as responsible for the development of cystinuria. Many of these mutations change a single nucleotide, or inserted or deleted a small number of nucleotides in the SLC7A9 gene. These changes result in a complex carrier protein abnormal operation, causing certain amino acids in the urine concentrate. Cystine is the only amino acid that forms crystals and stones in the bladder or kidneys, causing signs and symptoms of cystinuria.

This disease is inherited in an autosomal recessive pattern, which means that both copies of the gene in every cell have mutations. The parents of an individual with an autosomal recessive disorder each has a copy of the mutated gene, but usually show no signs and symptoms of the disease.

Tests in IVAMI: in IVAMI perform detection of mutations associated with cystinuria, by complete PCR amplification of the exons of SLC3A1 and SLC7A9, respectively, and subsequent sequencing genes.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).