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GENETICS: Second Sightings
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Paula A. Kiberstis

The inherited disorder retinitis pigmentosa (RP) affects 1 in 4000
individuals and is characterized by progressive degeneration of the
photoreceptor cells in the retina. Patients with this disorder commonly
develop tunnel vision and night blindness, which can then progress to
complete blindness. Although RP is genetically heterogeneous, several of
the loci have been identified as genes involved in the phototransduction
pathway.

In an appealing convergence of concept, researchers now report that two of
the genes responsible for autosomal dominant RP encode putative pre-
messenger RNA (mRNA) splicing factors: proteins that are needed to make
mature mRNA. McKie et al. show that the culprit gene on chromosome 17p13.3
(RP13) encodes an ortholog of yeast splicing factor PRP8, and Vithana et
al. show that the culprit gene on chromosome 19q13.4 (RP11) encodes an
ortholog of yeast splicing factor PRP31. Why defects in a fundamental
housekeeping function such as splicing would affect only the retina and not
other tissues is unclear, but the authors note that the retina is one of
the fastest metabolizing tissues in the body and may be particularly
vulnerable when splicing is disrupted. -- PAK

Human Molecular Genetics 10, 1555 (2001); Molecular Cell 8, 375 (2001).