Spastic paraplegia 11

Alternate names

SPG11; Hereditary spastic paraplegia mental impairment and thin corpus callosum; Autosomal recessive spastic paraplegia type 11; Hereditary spastic paraplegia 11; Nakamura Osame syndrome; Spastic paraplegia - intellectual deficit - thin corpus callosum

Definition

Spastic paraplegia 11 (SPG11) is a form of hereditary spastic paraplegia. People with SPG11 experience worsening muscle stiffness leading to eventual paralysis of the lower limbs, as well as a range of other neurologic symptoms that may include intellectual disability, speech difficulties (dysarthria), and reduced bladder control.

Cause

SPG11 is caused by mutations in the SPG11 gene.

Inheritance

Autosomal recessive inheritance, a 25% chance

SPG11 is inherited in an autosomal recessive manner. This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell. Affected people inherit one mutated copy of the gene from each parent, who is referred to as a carrier. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a:

• 25% (1 in 4) chance to be affected
• 50% (1 in 2) chance to be an unaffected carrier like each parent
• 25% chance to be unaffected and not be a carrier

Onset

• Age at time of symptom onset varies from infancy to early adulthood, with onset in infancy to adolescence being most common.
• Learning disability may begin in childhood.
• Most people experience a decline in intellectual ability and an increase in muscle weakness and nerve abnormalities over time.
• As the condition progresses, some people require wheelchair assistance (often 10 to 20 years after symptom onset).

Signs and symptoms

Signs and symptoms of SPG11 may include:

• Spasticity (progressive muscle stiffness)
• Paraplegia(eventual paralysis of the lower limbs)
• Numbness, tingling, or pain in the arms and legs
• Disturbance in the nerves used for muscle movement
• Intellectual disability
• Exaggerated reflexes of the lower limbs
• Speech difficulties (dysarthria)
• Reduced bladder control (Muscle wasting)

Less common features, include:

• Difficulty swallowing (dysphagia)
• High-arched feet
• Scoliosis
• Involuntary movements of the eyes

Diagnosis

The diagnosis of SPG11 is established in a proband with characteristic clinical and MRI findings and biallelic pathogenic variants in SPG11 identified on molecular genetic testing.[1].

Treatment

• Care for SPG11 is usually managed by a team including a primary care physician, neurologist, genetics professional (geneticist and/or genetic counselor), physical therapist, social worker, and psychologist.
• Treatment is focused on alleviating symptoms and may include:
• Medications for leg spasticity (antispastic drugs)
• Medications to assist in bladder control (anticholinergic antispasmodic drugs)
• Regular physician therapy
• Botulinum toxin and intrathecal baclofen for severe spasticity
• Regular outpatient clinic evaluations are recommended to adjust medications and physical therapy/rehabilitation routines.
• Routine brain MRI and electrophysiological investigations (muscle and nerve studies) may be useful to follow the progression of the disease.

Prognosis

The severity of symptoms in SPG11 worsen over time, with most individuals experiencing full clinical symptoms 10 years after onset. Most individuals with SPG11 require wheelchair assistance 10-20 years after onset. Intellectual disability and cognitive decline additionally typically worsen over time and may include short-term memory impairment, constant fluctuations in emotions, reduced verbal abilities, and attention deficits.

NIH genetic and rare disease info

• NIH info on Spastic paraplegia 11

Spastic paraplegia 11 is a rare disease.