Ganglioside-induced differentiation-associated protein-1 is mutant in Charcot-Marie-Tooth disease type 4A/8q21.

We previously localized and fine-mapped Charcot Marie Tooth 4A (CMT4A), the autosomal recessive, demyelinating peripheral neuropathy, to chromosome 8. Through additional positional cloning, we have identified a good candidate gene, encoding ganglioside-induced differentiation-associated protein-1 (GDAP1). We found three different mutations in four different Tunisian families-two nonsense and one missense mutation. How mutations in GDAP1 lead to CMT4A remains to be understood.     

PTK7/CCK-4 is a novel regulator of planar cell polarity in vertebrates

In addition to the apical-basal polarity pathway operating in epithelial cells, a planar cell polarity (PCP) pathway establishes polarity within the plane of epithelial tissues and is conserved from Drosophila to mammals. In Drosophila, a 'core' group of PCP genes including frizzled (fz), flamingo/starry night, dishevelled (dsh), Van Gogh/strabismus and prickle, function to regulate wing hair, bristle and ommatidial polarity. In vertebrates, the PCP pathway regulates convergent extension movements and neural tube closure, as well as the orientation of stereociliary bundles of sensory hair cells in the inner ear. Here we show that a mutation in the mouse protein tyrosine kinase 7 (PTK7) gene, which encodes an evolutionarily conserved transmembrane protein with tyrosine kinase homology, disrupts neural tube closure and stereociliary bundle orientation, and shows genetic interactions with a mutation in the mouse Van Gogh homologue vangl2. We also show that PTK7 is dynamically localized during hair cell polarization, and that the Xenopus homologue of PTK7 is required for neural convergent extension and neural tube closure. These results identify PTK7 as a novel regulator of PCP in vertebrates.     

A previously unidentified MECP2 open reading frame defines a new protein isoform relevant to Rett syndrome

Rett syndrome is caused by mutations in the gene MECP2 in approximately 80% of affected individuals. We describe a previously unknown MeCP2 isoform. Mutations unique to this isoform and the absence, until now, of identified mutations specific to the previously recognized protein indicate an important role for the newly discovered molecule in the pathogenesis of Rett syndrome.     

Sporting contests: seeing red? Putting sportswear in context

The shirt colour worn by sportsmen can affect the behaviour of the competitors, but Hill and Barton show that it may also influence the outcome of contests. By analysing the results of men's combat sports from the Athens 2004 Olympics, they found that more matches were won by fighters wearing red outfits than by those wearing blue; they suggest that red might confer success because it is a sign of dominance in many animal species and could signal aggression in human contests. Here we use another data set from the 2004 Olympics to show that similar winning biases occur in contests in which neither contestant wears red, indicating that a different mechanism may be responsible for these effects.