Spinal muscular atrophy SMA is a genetic condition which affects the nerves that control muscle movement — the motor neurons. There is wide variability in age of onset, symptoms and rate of progression of SMA and it is often classified into types one to four based on the physical milestones achieved. Adults are usually diagnosed with SMA type 4 in their second or third decade of life, usually after the age of 35, although some may have symptoms as early as 18 years of age. This type of SMA is much less common than types one to three. Symptoms usually include mild muscle weakness, tremor and twitching.
Spinal Muscular Atrophy
Looking After Yourself If You Have Adult Onset SMA - Spinal Muscular Atrophy UK
Alternative titles; symbols. Spinal muscular atrophy is characterized by degeneration of the anterior horn cells in the spinal cord, leading to symmetric muscle weakness and wasting. See also autosomal recessive adult-onset proximal spinal muscular atrophy SMA4; , caused by defect in the SMN1 gene , and autosomal dominant childhood-onset proximal SMA Pearn reported 13 patients from 6 kindreds with autosomal dominant proximal spinal muscular atrophy. Median age at disease onset was 37 years. Pearn suggested that a separate gene was responsible for autosomal dominant SMA with childhood onset birth to 8 years. Richieri-Costa et al.
Spinal Muscular Atrophy Type 4
You may prefer to read this as a printed version — use the print button at the top right of this page. If you are in the UK, you can ask us to send it to you in booklet form. This guide is for adults who have had a recent diagnosis of an adult onset form of SMA.
Spinal muscle atrophy SMA is a serious heritable condition characterized by the loss of motor neurons, or nerve cells responsible for carrying instructions from the brain to the muscles to control their movement. Without these nerve cells, muscles weaken and atrophy. Patients with SMA may have difficulty standing, walking, and dressing.