Spinocerebellar ataxia 28

Alternate names

SCA28; Spinocerebellar ataxia type 28

Definition

Spinocerebellar ataxia 28 (SCA28)is a slowly progressive movement disorder that typically begins in early adulthood (but can affect children and older adults as well).

Cause

SCA28 is caused by changes in the AFG3L2 gene.

Inheritance

Autosomal dominant pattern, a 50/50 chance.

Spinocerebellar ataxia type 28 (SCA28) is inherited in an autosomal dominant manner.

Signs and symptoms

Early signs and symptoms include problems with coordination and balance when walking (gait ataxia), speech and swallowing difficulties (dysarthria), over-reactive reflex reactions in knees and ankles (hyperreflexia), weakness in the muscles that control eye movement (ophthalmoparesis), uncontrolled movement of the eye (nystagmus) and drooping eyelid (ptosis). The symptoms worsen very slowly over time.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Dysarthria(Difficulty articulating speech)
• Gait ataxia(Inability to coordinate movements when walking)
• Limb ataxia
• Lower limb hyperreflexia(Overactive lower leg reflex)

30%-79% of people have these symptoms

• Babinski sign
• Nystagmus(Involuntary, rapid, rhythmic eye movements)
• Ophthalmoparesis(Weakness of muscles controlling eye movement)
• Ptosis(Drooping upper eyelid)
• Slow saccadic eye movements(Slow eye movements)

5%-29% of people have these symptoms

• Dystonia
• Kinetic tremor
• Parkinsonism

1%-4% of people have these symptoms

• Depressivity(Depression)
• Head tremor
• Limb dystonia
• Memory impairment(Forgetfulness)
• Rigidity(Muscle rigidity)
• Spasticity(Involuntary muscle stiffness, contraction, or spasm)

Diagnosis

Spinocerebellar ataxia type 28 (SCA28) should be suspected in individuals with the following:[1].

• Onset generally in young adulthood (but with a wide range: ages 3-76 years)
• A slowly progressive gait disorder resulting from cerebellar impairment
• Cerebellar dysarthria
• Oculomotor abnormalities including ophthalmoparesis, nystagmus and ptosis
• Hyperreflexia or brisk deep tendon reflexes
• Brain MRI showing cerebellar atrophy predominantly of the superior vermis, with sparing of the brain stem
• A family history consistent with autosomal dominant inheritance

Establishing the Diagnosis The diagnosis of SCA28 is established in a proband with typical clinical findings and identification of a heterozygous pathogenic variant in AFG3L2 by molecular genetic testing.

Treatment

At present, only symptomatic treatments are available. These include the following:

• Crutches (less often canes) and walkers
• Home adaptations including grab bars for the bathtub or shower chairs and raised toilet seats as needed
• Physical therapy to ameliorate coordination difficulties, especially with tasks such as eating, dressing, walking, and bathing
• Stretching exercise for those with pyramidal involvement to avoid contractions and lack of comfort during sleep
• Speech/language therapy for dysarthria and swallowing difficulties
• Surgical intervention as needed for severe ptosis

Prevention of Secondary Complications

Psychological support helps affected individuals cope with the consequences of the disease. Weight control can facilitate ambulation. To avoid complications such as aspiration pneumonia, thickened feeds or gastrostomy should be considered.

NIH genetic and rare disease info

• NIH info on Spinocerebellar ataxia 28

Spinocerebellar ataxia 28 is a rare disease.