A recent study has found that ‘clock’ genes that help to regulate the body’s circadian rhythm may be affected by spinal muscular atrophy. The original paper, which is published in Human Molecular Genetics, can be found here.
About Spinal Muscular Atrophy
Spinal muscular atrophy (SMA) is a genetic condition that causes issues with movement and muscle weakness. There are several different types of SMA, each with its own typical symptoms and onset-age. Types 1, 2, 3, and 4 are caused by changes to the SMN1 gene.
Some common symptoms of SMA include breathing and swallowing difficulties, floppy or weak arms and legs, tremors, movement problems, and bone and joint issues, such as a curved spine. However, there is a wide range in how severely people can be affected. It is estimated that approximately one in every 10,000 babies are born with the condition.
What Circadian Rhythms Are
Circadian regulation, or rhythm, is an internal 24-hour body clock that affects how sleepy or alert people feel at different times. According to the National Sleep Foundation, the circadian cycle makes most adults feel the most tired or lacking in energy between around 2-4 am, and between 1-3 pm, although the exact times differ between people. There is also some evidence that circadian rhythms may affect health and well-being, and that disrupting the rhythms can lead to sleep disruption and disturbances to the metabolism (the chemical reactions in the body). A group of genes known as clock genes play an important role in regulating circadian rhythms.
About the Study
Since metabolic and sleep disturbances have been linked to both circadian rhythm disruption and SMA, researchers carried out a study to investigate the link between the two.
Using animal models of SMA, the research team looked at how the genes linked to circadian rhythms behaved in different types of metabolic tissues and in the spinal cord.
The Findings
The results showed that clock genes, responsible for regulating circadian rhythms, showed altered (dysregulated) expression in tissues that were also affected by SMA during disease progression.
Furthermore, it was found that the daily expression of the SMN gene depended on age and body area (tissue type). It was shown that controlled light exposure could alter the circadian rhythm genes and reduce some of the effects of severe SMA in the mouse models, and may improve weight and survival.
The authors of the study conclude that these results provide evidence that tissues affected metabolically by SMA tend to also show altered expression (dysregulation) of circadian rhythm genes. It seems as though there is a link between the SMN gene, circadian rhythms, and metabolic processes.
For more detailed information about exactly what the researchers found, check out the published study here.
