Healthy parents with unremarkable family history have the child with multiple developmental defects. Cytogenetic analysis revealed the trisomy 13 in the somatic cells (Patau syndrome). What phenomenon has caused the defects?

Answer options

1. Abnormal gametogenesis
2. Chromosomal mutation
3. Somatic mutation
4. Dominant mutation
5. Recessive mutation

Explanation

Patau syndrome is a syndrome caused by a chromosomal abnormality, in which some or all of the cells of the body contain extra genetic material from chromosome 13.