CTNS mutations in African American patients with cystinosis

Robert Kleta, Yair Anikster, Cynthia Lucero, Vorasuk Shotelersuk, Marjan Huizing, Isa Bernardini, Margaret Park, Jess Thoene, Jerry Schneider, William A. Gahl*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Cystinosis, an autosomal recessive lysosomal storage disorder, is rarely diagnosed in African Americans. The disease results from mutations in the gene CTNS; at least 55 such mutations have been reported. By far the most common is a 57,257-bp deletion of Northern European origin encompassing most of the CTNS gene. We performed mutation analysis on DNA from four African American patients with cystinosis. In one individual with classical, nephropathic cystinosis, we identified a new molecular defect, i.e., a homozygous GT→CC substitution at the +5 position of IVS 5 of CTNS (IVS 5+5 GT→CC). The out-of-frame splicing of exon 5 creates a null allele consistent with the patient's severe phenotype. Two patients were heterozygous and one homozygous for the common 57-kb deletion allele, reflecting the admixture of African and Northern European gene pools in North America. The two African Americans heterozygous for the 57-kb deletion were also hemizygous for a 928G→A change, associated with ocular or nonnephropathic cystinosis. These two individuals are the only known African Americans with ocular cystinosis. We conclude that the diagnosis of cystinosis should be entertained in African Americans with symptoms of the disease, and that mutation analysis for the 57-kb deletion should be considered in this group of patients.

Original languageEnglish
Pages (from-to)332-337
Number of pages6
JournalMolecular Genetics and Metabolism
Issue number3
StatePublished - 2001
Externally publishedYes


  • African American
  • Mutation analysis
  • Ocular cystinosis
  • Splicing


Dive into the research topics of 'CTNS mutations in African American patients with cystinosis'. Together they form a unique fingerprint.

Cite this