A new 2-base pair deletion in the RPGR gene in a black family with X-linked retinitis pigmentosa.

OBJECTIVE

To report the genetic and ophthalmic findings in a black family with X-linked retinitis pigmentosa resulting from a newly identified mutation in the RPGR (retinitis pigmentosa GTPase regulator) gene.

PATIENTS

Four affected hemizygotes with retinitis pigmentosa and 2 obligate carriers were examined. Two unaffected family members, 1 woman and her unaffected son, were also examined.

METHODS

Patients underwent a routine ocular examination including slitlamp examination and a dilated fundus examination. Certain patients also underwent testing with Goldmann visual field kinetic perimetry and electroretinography. DNA screening from affected male patients, 2 obligate carriers, and 2 unaffected family members was performed to determine the presence of any mutation in the RPGR gene.

RESULTS

A 2-base pair deletion in exon 13 of the RPGR gene that creates a frameshift was found to segregate with the retinal disease in affected males and the carrier state in female heterozygotes in this family. The ophthalmic findings in hemizygotes and carriers were within the spectrum of findings characteristically noted in families with X-linked retinitis pigmentosa. In 2 obligate carriers, a tapetal-like reflex was not clinically apparent.

CONCLUSIONS

The described mutation is the first RPGR gene mutation reported in a black family. A 2-base pair deletion in exon 13 segregates with a clinical phenotype of X-linked retinitis pigmentosa.