What is the definition of Spastic Paraplegia Type 11?
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. Additionally, the tissue connecting the left and right halves of the brain (corpus callosum) is abnormally thin in most individuals with SPG11. Onset of symptoms typically occurs during infancy or adolescence. SPG11 is caused by mutations in the SPG11 gene and is inherited in an autosomal recessive fashion. Treatment is focused on managing symptoms and may include physical therapy and antispastic medications to prolong muscle control.
What are the alternative names for Spastic Paraplegia Type 11?
- 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
What are the symptoms for Spastic Paraplegia Type 11?
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
- Involuntary movements of the eyes
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).
What are the current treatments for Spastic Paraplegia Type 11?
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.
What is the outlook (prognosis) for Spastic Paraplegia Type 11?
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.
Is Spastic Paraplegia Type 11 an inherited disorder?
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