G proteins and cognitive ability
Ruano and colleagues add a spin to pathway-association analysis by grouping the variants from genes which share cellular functionality. The thought is that many pathways will be affected by a convergent set of functional proteins. The authors use such a process to identify variants that are associated with cognitive ability and find that the group of SNPs from synaptic heterotrimeric G proteins is associated with cognitive ability.

Aggrecan and osteochondritis dissecans
Aggrecan is a heavily glycosylated proteoglycan that that is crucial for cartilage function. Adding to the list of diseases caused by mutations in ACAN, the gene encoding aggrecan, here, Stattin and colleagues identify an ACAN mutation causative for familial osteochronditis dissecans in a large Swedish family. Extensive biochemical analyses reveal the detrimental effects of the mutation, which include altered interactions with other matrix proteins.

GRXCR1 and Grxcr1 mutations cause DFNB25 and the pirouette mouse phenotype, respectively
Schraders and colleagues use homozygosity mapping to narrow the DNFB25 locus by studying numerous families and an isolated case of hearing impairment. Sequencing of GRXCR1 within the shared homozygous region reveals several different pathogenic mutations. Meanwhile, Odeh and colleagues describe mutations in Grxcr1 to be responsible for the pirouette mouse phenotype, which includes deafness and circling behavior. A potential function of GRXCR1 is predicted to be that of actin cytoskeletal remodeling.

Distribution and most recent common ancestor of the 17q21 inversion
There is a region of complete linkage disequilibrium on 17q21 that has been found to harbor an inversion of about 900 kb. The most common version of the chromosome is called H1, and the inverted orientation of the chromosome is called H2. Previous estimates have suggested that the inversion occurred 2–3 million years ago, but there has been controversy about that timeline. Here, Donnelly and colleagues collect data from populations from around the world and combine it with previously published data sets and data from non-human primates to further examine this matter.

Association tests in structured samples
In case-control analyses, false positives can result from hidden structure, and correction methods cannot always handle all types of data, particularly if related individuals are included. Family-based methods are robust to population structure, but they often lack power and require additional data that can be difficult to obtain. Thornton and McPeek address these issues with the introduction of ROADTRIPS, a method which can perform genome-wide association analyses on case-control samples in the presence of both population and pedigree structure.