Jokela type spinal muscular atrophy (SMAJ), also known as late-onset spinal motor neuronopathy (LOSMoN), is an ultra-rare neuromuscular disorder characterized by muscle twitches and cramps. The symptoms appear in adulthood and gradually progress. The disease is caused by a mutation in the ''

CHCHD10 Coiled-coil-helix-coiled-coil-helix domain-containing protein 10, mitochondrial, also known as Protein N27C7-4 is a protein that in humans is encoded by the ''CHCHD10'' gene. Structure The ''CHCHD10'' gene is located on the Locus (genetic ...

'' gene and is inherited in an autosomal dominant pattern. It was first described by the Finnish neurologist Manu Jokela in 2011.

Symptoms and signs

The first symptoms include muscle cramps and

muscle twitch A fasciculation, or muscle twitch, is a spontaneous, involuntary muscle contraction and relaxation, involving fine muscle fibers. They are common, with as many as 70% of people experiencing them. They can be benign, or associated with more serio ...

es affecting the upper and lower limbs. They appear usually after age of 40. The disease is slowly progressive with adult onset and results in weakness and mild

muscle atrophy Muscle atrophy is the loss of skeletal muscle mass. It can be caused by immobility, aging, malnutrition, medications, or a wide range of injuries or diseases that impact the musculoskeletal or nervous system. Muscle atrophy leads to muscle weakness ...

. The disease does not affect life expectancy. However, it is difficult to differentiate the disease from a more fatal

amyotrophic lateral sclerosis Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...

in diagnosis. Ultimately, SMAJ can lead to reduced ability in motor function for skills such as walking. SMAJ may also reduce one’s nerve function and ability to sense vibrations.

Cause

Epidemiology

it has been found only in a handful of families living in the

Karelia Karelia ( Karelian and fi, Karjala, ; rus, Каре́лия, links=y, r=Karélija, p=kɐˈrʲelʲɪjə, historically ''Korjela''; sv, Karelen), the land of the Karelian people, is an area in Northern Europe of historical significance for ...

region of Finland.

History

The disease was first described by the Finnish neurologist Manu Jokela in 2011 who has also identified the gene responsible for the disease.

References

External links

Rare diseases Motor neuron diseases {{Finland-stub