Nature Genetics pp 585 - 587

A potential barrier to the therapeutic use of human embryonic stem cells appears to be less of a concern than previously thought, according to a study published in the June issue of Nature Genetics. Peter Rugg-Gunn and colleagues report that the status of so-called 'imprinted' genes, in which only one copy of the gene is expressed, is generally normal in a sampling of such genes in a series of human stem cell lines grown in culture dishes.

Previous work had shown that imprinted genes in embryonic stem cells generated from mouse embryos had altered expression patterns. As such aberrant gene expression might affect the viability or proper functioning of the cells when introduced into individuals as a replacement for diseased cells, it was feared that this represented a major obstacle to their therapeutic use.

Rugg-Gunn and colleagues examined six genes and three other regions of the human genome that are involved in imprinting -- all but one of which had the normal pattern of expression in the human stem cell lines. Although they note that it is possible that the expression of other genes might be altered in human embryonic stem cells, the current work suggests a greater degree of stability than anticipated.

Nature Genetics pp 607- 612

A genetic variation associated with susceptibility to lumbar disc disease, one of the most common musculoskeletal disorders has been identified in a study published in the June issue of Nature Genetics.

Lumbar disc disease, caused by degeneration of intervertebral discs of the lumbar spine, is a primary cause of lower back pain. While previous studies have provided evidence for an important genetic component to development of lumbar disc disease, the mechanism leading to disease remains largely unknown. Shiro Ikegawa and colleagues describe an altered protein found in cartilage of affected individuals, based on results taken from two Japanese populations of patients and healthy controls. This protein is shown to interact with a growth factor previously associated with connective tissue disorders, suggesting a likely role for this protein in progression of the disease in intervertebral tissues.