SNP Shot: Genomic Insights

Spastic paraplegia type 4 (SPG4) is the most frequent form of hereditary spastic paraplegia, a group of inherited conditions causing progressive muscle stiffness (spasticity) and walking difficulties, primarily in the legs. Hereditary spastic paraplegias are classified as either pure or complex. Pure forms mainly affect the lower limbs, causing spasticity and impaired walking. Complex forms, however, involve broader issues affecting the nervous system, including the brain, and the peripheral nervous system responsible for transmitting sensory information and controlling muscles. Complex forms can also involve problems outside the nervous system. SPG4 is typically a pure hereditary spastic paraplegia, though rare complex cases exist.

Similar to other hereditary spastic paraplegias, SPG4 is characterized by leg muscle spasticity and weakness. Individuals with SPG4 may also exhibit exaggerated reflexes (hyperreflexia), ankle spasms, high arches in their feet (pes cavus), and impaired bladder control. Generally, SPG4 primarily impacts nerve and muscle function in the lower body.

Inheritance:

SPG4 follows an autosomal dominant inheritance pattern. This means that possessing just one copy of the mutated gene in each cell is enough to cause the condition. In most instances, an affected individual inherits the mutated gene from one parent who also has the condition. However, some cases arise from new mutations in the gene, occurring in individuals with no family history of SPG4.