The SMN1 (Survival Motor Neuron 1) gene is critical for producing a protein essential for the survival and function of motor neurons. These neurons transmit signals to muscles and enable voluntary movements. Mutations or deletions in the SMN1 gene lead to spinal muscular atrophy (SMA), a genetic disorder that causes progressive muscle weakness and wasting. SMA is one of the leading genetic causes of infant mortality, and the onset and severity of symptoms determine the form of the disease.
More Information
The SMN1 gene is located on chromosome 5 and produces the SMN protein, crucial for motor neuron maintenance. The SMN1 gene has a near-identical counterpart, SMN2, which can partially compensate for the loss of SMN1 function. However, SMN2 produces a truncated version of the less effective protein, resulting in SMA's characteristic symptoms. The number of copies of the SMN2 gene influences the severity of spinal muscular atrophy. Individuals with more copies of SMN2 tend to have milder forms of the disease, while those with fewer copies experience more severe symptoms. Genetic testing for SMN1 is essential in identifying these deletions or mutations, as early diagnosis enables timely intervention and the potential for effective treatments.
The MLPA method used for SMN1 testing is particularly effective in detecting gene deletions and duplications. MLPA works by amplifying specific DNA regions targeted by probes, allowing the detection of the number of gene copies present. This technique is more sensitive than traditional PCR or sequencing methods, especially when dealing with copy number variations common in SMN1 mutations. MLPA provides a quick, reliable, and cost-effective approach to diagnosing spinal muscular atrophy, particularly in cases where traditional genetic testing may be less effective.
In addition to diagnosing symptomatic patients, the SMN1 MLPA test is valuable in prenatal screening. It can be used to identify spinal muscular atrophy in unborn children through analysis of DNA from parents or amniotic fluid. Early detection through prenatal screening allows for better-informed decisions and the possibility of early intervention. For family planning, carrier screening using the SMN1 test can determine whether an individual carries a mutated SMN1 gene, which benefits couples considering pregnancy. If both parents are carriers, there is a 25% chance their child will inherit two mutated copies of the gene and develop spinal muscular atrophy.
See also: SMN1 and SMN2 Genes, Genetic Testing
