Pregnancy planning

A very rare situation has developed for a family from the southern region of the Russian Federation. The young couple gave birth to their first child, who died immediately after birth. The second child survived, but was diagnosed with a very severe neuromuscular disease. The child is seriously disabled. He underwent biochemical studies aimed at diagnosing hereditary diseases - no changes were revealed. Research on chromosome abnormalities - negative; various genetic analyzes (gene panels, targeting studies of specific genes, sequencing of the complete exome, sequencing of the mitochondrial genome) did not reveal any pathological changes. The family really wants to have children. After two pregnancies, they are afraid of having another sick child. In complete despair, they turned to the fund for help. The family underwent a study of the complete genome in the TRIO format (mom, dad, child), which revealed a rare genetic breakdown in the currently poorly studied genome region. It turned out that both parents passed on to the child an absolutely identical, very small, unique genetic abnormality, which caused the child's illness. Given the identity of the genetic changes in mom and dad, it was suspected that they are related, which was confirmed upon questioning.