Wissinger Lab

Molecular Genetics Laboratory

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Achromatopsia

Achromatopsia (ACHM) is a rare autosomal recessive cone disorder with an estimated prevalence of one in 30,000 to one in 50,000. It typically manifests within the first weeks or months of life and affected individuals suffer from nystagmus, photophobia, severely reduced visual acuity (<0.1 or 20/200) and color blindness. Rod-mediated vision remains largely unaffected in ACHM patients. Originally thought to be a stationary disease, the application of optical coherence tomography has demonstrated progressive foveal outer retinal degeneration at least in some patients.

Most patients suffer from complete ACHM, with a total lack of function of all three types of cones. Rarely, patients have incomplete ACHM, with symptoms similar to those of individuals with complete ACHM, but generally less severe (i.e., residual color vision or cone responses on electroretinography, higher visual acuity, less photophobia, or no nystagmus).

Five genes, CNGA3, CNGB3, GNAT2, PDE6C, and PDE6H, all encoding functional components of the phototransduction cascade in cone photoreceptors, have been implicated in ACHM. Recently, we have shown that also mutations in ATF6, encoding a key regulator of the unfolded protein response and cellular endoplasmic reticulum homeostasis, can also cause ACHM.

Our group studies the molecular genetic basis of ACHM in individual patients and families as well as on the population level.

Main objectives of the project are:

  1. Provide research testing for patients with ACHM
  2. Reference center for the genetic testing of clinically diagnosed and genetically confirmed ACHM patients
  3. Determination of mutation spectrum and mutation rates in ACHM