Symptoms SEPN1-related myopathy

Children with SEPN1-related myopathy often have hypotonia (low muscle-tone, floppiness) at birth. They may have difficulty in achieving motor milestones, such as head control, sitting unaided, crawling or walking.

Most children with SEPN1-related myopathy develop a curvature of the spine (scoliosis), which needs to be carefully monitored.

People with SEPN1-related myopathy may also develop joint ‘contractures’ or ‘tightness’, meaning they may be unable to move the joints as freely as a healthy person. Physiotherapy can help to prevent or slow the progression of joint contractures, so it is important to work with a physiotherapist soon after diagnosis to establish a programme of exercises.

Because the muscles that assist breathing are affected, children with SEPN1-related myopathy experience breathing problems while sleeping. It is therefore essential to monitor lung function on a regular basis and to perform annual overnight ‘sleep studies’. Night-time breathing problems can cause children to feel tired during the day, have headaches on waking in the morning, have loss of appetite for breakfast and lose weight.

A decrease in lung function can also result in frequent chest infections. If these signs are present, or if the level of oxygen recorded during an overnight sleep study is not satisfactory, it is essential that children are referred to a respiratory clinician to initiate night-time non-invasive ventilation (NIV). NIV entails using a special facial or nasal mask attached to a small machine that pumps air into the lungs to maintain adequate ventilation.

Another frequent problem encountered by people with SEPN1-related myopathy is failure to gain weight normally. It is therefore essential to monitor weight (and height) to be sure that children with SEPN1-related myopathy receive enough food and energy. Some people with SEPN1-related myopathy may need to take nutritional supplements. Rarely, a small surgical procedure called a gastrostomy may be recommended, which entails inserting a tube directly into the stomach, and ensures an adequate level of nutrition is ingested.

Can a child with SEPN1-related myopathy learn to walk?

The severity of this condition varies greatly from person to person. However, children with SEPN1-related myopathy invariably achieve the ability to walk, albeit at a delayed age. Most people with SEPN1-related myopathy maintain the ability to walk throughout their lives.