The reason was the diagnosis of SMA in her younger brother, who, at the age of about 16 years, manifested the symptoms of SMA: lower limb muscle weakness, leading to difficulty walking, poor balance, tremors (genetically confirmed: the presence of deletions of exons 7 and 8 in the SMN1 gene, four copies of the SMN2 gene). Here, SMN1 is linked to proximal spinal muscular atrophy.