Spastic paraplegia type 5B, recessive

Spastic paraplegia type 5B, recessive
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Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Progressive spasticity and weakness of the lower limbs
Complications	N/A
Onset	Childhood or adolescence
Duration	N/A
Types	N/A
Causes	Genetic mutation in the CYP7B1 gene
Risks	N/A
Diagnosis	Genetic testing, clinical evaluation
Differential diagnosis	N/A
Prevention	N/A
Treatment	Symptomatic management, physical therapy
Medication	N/A
Prognosis	Variable
Frequency	N/A
Deaths	N/A

Spastic paraplegia type 5B, recessive (SPG5B) is a rare hereditary spastic paraplegia (HSP) characterized by progressive spasticity and weakness of the lower limbs. It is caused by mutations in the CYP7B1 gene, which is inherited in an autosomal recessive manner.

Clinical Features

Patients with SPG5B typically present with progressive spasticity and weakness in the lower limbs. The onset of symptoms usually occurs in childhood or adolescence, although the age of onset can vary. The spasticity leads to difficulties with walking and balance, and over time, patients may require assistive devices for mobility.

Genetics

SPG5B is caused by mutations in the CYP7B1 gene, which encodes the enzyme oxysterol 7-alpha-hydroxylase. This enzyme is involved in the metabolism of cholesterol and bile acids. Mutations in CYP7B1 disrupt this metabolic pathway, leading to the accumulation of neurotoxic intermediates that contribute to the degeneration of motor neurons.

The condition is inherited in an autosomal recessive pattern, meaning that an affected individual must inherit two copies of the mutated gene, one from each parent. Carriers, who have only one copy of the mutation, typically do not show symptoms.

Diagnosis

Diagnosis of SPG5B involves a combination of clinical evaluation and genetic testing. A neurologist may suspect HSP based on the clinical presentation of spasticity and weakness. Genetic testing can confirm the diagnosis by identifying mutations in the CYP7B1 gene.

Management

There is currently no cure for SPG5B, and treatment is focused on managing symptoms and improving quality of life. Physical therapy is often recommended to maintain mobility and reduce spasticity. Medications such as baclofen or tizanidine may be prescribed to help manage spasticity. Assistive devices, such as canes or walkers, can aid in mobility.

Prognosis

The prognosis for individuals with SPG5B varies. Some patients may experience a slow progression of symptoms, while others may have a more rapid decline in mobility. Early intervention with physical therapy and supportive care can help improve outcomes.

Research Directions

Ongoing research is focused on understanding the pathophysiology of SPG5B and developing potential therapies. Gene therapy and other molecular approaches are being explored as potential treatments for hereditary spastic paraplegias.

Also see

• Hereditary spastic paraplegia
• Autosomal recessive inheritance
• CYP7B1 gene
• Spasticity