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What is spinal muscular atrophy? -

Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disease. It's a congenital condition in which the spinal cord does not form normally. It makes the muscles weaker and causes problems with movement.

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First case discovered -

The first case of what is now called spinal muscular atrophy was described in 1891 by Austrian neurologist Guido Werdnig (pictured) and Johann Hoffmann. The condition was found in two baby brothers.

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What causes spinal muscular atrophy? -

The disease is caused by a mutation in the survival motor neuron 1 (SMAN1) gene.

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(SMAN1) gene -

SMAN1 is responsible for producing survival motor neuron (SMN) protein, which maintains the health and normal function of motor neurons.

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Spinal muscular atrophy -

Loss of these neurons in the spinal cord prevents signaling between the brain and skeletal muscles.

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Spinal muscular atrophy -

The degeneration of motor neurons leads to a gradual decrease in the mass and strength of muscles (atrophy).

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How do you get spinal muscular atrophy? -

This rare neuromuscular disorder is inherited. In most cases, a child can only be born with SMA if both of their parents have a faulty gene that causes the condition. The parents will not usually have SMA themselves.

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Infants with SMA -

SMA is usually diagnosed in infancy or early childhood, and if left untreated is the most common genetic cause of infant death.

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Spinal muscular atrophy -

Around one in every 40 to 60 people is a carrier of the main faulty gene that causes SMA.

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Types of SMA -

There are four types of SMA: Type 1 is the most common and severe form of SMA; Type 2 is an intermediate form; Type 3 is a milder form; and Type 4 is very rare.

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Type 1 -

Type 1, also known as infant-onset SMA, comprises 60% of all cases of the disease. Affected toddlers are unable to sit up, so-called "non-sitters."

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Type 2 -

Intermediate SMA is usually diagnosed between seven and 18 months. Affected youngsters can typically sit up (also known as "sitters") without help.

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Type 3 -

Type 3 is sometimes referred to as juvenile-onset SMA. The condition is commonly diagnosed after 18 months of age, but before the child reaches three years old. While very often able to walk, mobility will decrease as they grow older, eventually resulting in the need for a wheelchair.

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Type 4 -

Type 4 is characterized by mild, gradual limb weakness that usually occurs after 30 years of age but can manifest itself as early as age 18. This is the rarest form of SMA.

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Symptoms of SMA -

Infants who have noticeable SMA symptoms at or shortly after birth usually are very weak. SMA affects every child differently, but common symptoms include poor head control, lack of muscle tone, weak cough, and progressive difficulty in chewing and swallowing.

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SMA symptoms -

As they approach two years old, affected children will demonstrate further muscle weakness and may develop spinal problems such as scoliosis (curvature of the spine).

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SMA -

Aged three and beyond, symptoms are noticeably more severe as muscles weaken and ache. Muscles in the legs are more prone to the effects of the disease than those in the arms.

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Symptoms of SMA -

As the disease takes hold, affected individuals will likely experience amplified mobility issues compounded by twitching or shaking muscles, joint overuse symptoms, and further breathing and swallowing difficulties.

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SMA -

Fortunately, SMA does not affect intelligence or cause learning difficulties.

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Diagnosis -

Timing of diagnosis is crucial for spinal muscular atrophy. The earlier the condition is identified, the quicker treatment and supportive care can be implemented. A genetic blood test will be carried out to confirm or rule out the presence of the disease.

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Managing SMA -

There is currently no cure for spinal muscular atrophy. Instead, treatment and support is available to manage the symptoms and help people with SMA obtain the best possible quality of life.

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SMA care -

The level of care for SMA patients may range from proactive to palliative. Treatment may involve exercises and equipment to help with movement such as this exoskeleton designed for children.

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Back brace -

Those with SMA often wear a specially designed back brace to help support the back and encourage the spine to grow correctly.

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Custom-made wheelchairs -

Custom-made wheelchairs are designed to meet the specific needs of SMA suffers. They include, for example, special motion control dials, which greatly assist in mobility and offer a degree of independence.

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Treatment orthopaedic care -

Equipment is also available to assist in breathing. Indeed, proactive care refers to procedures that address both acute problems and the day-to-day management of a patient's medical needs. These procedures include airway clearance and ventilator support, dietary advice, and orthopedic care.

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Acute care -

Acute care is actioned when a patient needs to go into hospital for specialist observation. There, braces or surgery to treat problems with the spine or joints will likely be recommended.

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Treatment with new medicines -

Treatment with new medicines approved for spinal muscular atrophy on children with juvenile-onset SMA has resulted in motor function improvements and disease activity stabilization.

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Physiotherapy -

Treatment for SMA extends to physiotherapy and occupational therapy, with particular emphasis on stretching and positioning.

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Help -

There are numerous national and international organizations that offer up a wide range of information about SMA, care, and related topics. Start with a search online.

Sources: (Together in SMA) (Boston Children's Hospital) (American Academy of Neurology) (Spinal Muscular Atrophy UK) (Cure SMA)

See also: What is juvenile arthritis?

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