Description

Spinal muscular atrophy with type 1 respiratory distress (SMARD1) is a fatal neurodegenerative childhood disease characterized by the selective death of motor neurons, the cells responsible for transmitting the signal from the brain to the muscles. The pathology is characterized by the involvement of the respiratory muscles and a predominantly distal involvement of the musculature of the limbs. It usually occurs between two and six months of life; progressive muscle weakness leads to early degeneration of spinal cord motor neurons, resulting in muscle atrophy and death by respiratory paralysis. To date there is no effective cure for SMARD1, which is a devastating disease for both patients and their families. The presence of atypical cases and milder phenotypes determines a variability in the casuistry that suggests the presence of elements modifying the disease that could alter the onset and the severity of the same. The disease is associated with genetic mutations in the gene that codes for the immunoglobulin μ-binding protein 2 (IGHMBP2) located on chromosome 11q13. The human gene is implicated in DNA replication and RNA metabolism, but its precise function in these processes and the reason why mutations in the IGHMBP2 gene are the cause of selective motor neuron death has not yet been clarified, although the defects in RNA metabolism have already been associated with neurodegenerative disorders. A mutation at the splicing site of the murine Ighmbp2 gene is responsible for a neuromuscular disorder similar to the human disease in the mouse, which is used in the laboratory as an animal model for the study of SMARD1.

External Information

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