News on amyotrophic lateral sclerosis, congenital muscular dystrophy, Friedreich's ataxia and spinal muscular atrophy
Amyotrophic lateral sclerosis (ALS)
Mutations in the gene for the FUS protein, recently identified as a cause of amyotrophic lateral sclerosis (ALS), have been found to cause the FUS protein to become part of so-called "stress granules" in cells that are subjected to elevated temperatures and other challenges. The findings indicate a potential link between FUS gene mutations and cellular pathways involved in stress responses. See Mutant FUS proteins that cause amyotrophic lateral sclerosis incorporate into stress granules.
Congenital muscular dystrophies (CMD)
Researchers have created a mouse model of two types of congenital muscular dystrophy (CMD), known as muscle-eye-brain disease (MEB) and Walker-Warburg syndrome (WWS), both of which can result from mutations in the fukutin-related protein gene. The mouse model, which has a mutation in the fukutin-related protein gene, develops brain, eye and skeletal muscle defects similar to those seen in MEB and WWS and should help speed research in these diseases. See Fukutin-related protein is essential for mouse muscle, brain and eye development, and mutation recapitulates the wide clinical spectrums of dystroglycanopathies.
Friedreich's ataxia (FA)
Scientists have identified two "transcription factor" proteins and a specific DNA sequence in the frataxin gene that work together to regulate levels of frataxin protein production. Frataxin is deficient in Friedreich's ataxia (FA), and the findings could provide a new approach to increasing its synthesis. See Expression of human frataxin is regulated by transcription factors SRF and TFAP2.
Spinal muscular atrophy (SMA)
An MDA-supported research group has reported that deficiencies of SMN, the underlying cause of most cases of spinal muscular atrophy (SMA), result in reduced levels of alpha-synuclein, a protein believed to be involved in protection of nerve cells and nerve-cell signal transmission. See Alpha-synuclein loss in spinal muscular atrophy.
Six months of treatment with valproic acid and carnitine failed to benefit young, nonambulatory children ages 2-8 with spinal muscular atrophy (SMA) in a 61-person trial. Excessive weight gain was the most frequent treatment-related averse event. See SMA CARNI-VAL Trial Part I: Double-Blind, Randomized, Placebo-Controlled Trial of L-Carnitine and Valproic Acid in Spinal Muscular Atrophy for a complete analysis of this clinical trial.
A large, North American family with a dominantly inherited type of spinal muscular atrophy (SMA) was found to have a disorder linked to a specific region of chromosome 14. Most SMA is recessively inherited and arises from mutations in the SMN gene on chromosome 5. The study was supported in part by MDA. See Dominant spinal muscular atrophy with lower extremity predominant: linkage to 14q32.