Ehlers-Danlos Syndrome Classical Type COL5A1

A 19-year-old woman with recurrent shoulder dislocations, bilateral patellar instability, hyperextensible velvety skin, and atrophic scars is evaluated for suspected Ehlers-Danlos Syndrome. Her pedigree demonstrates the inheritance pattern marked **A** in the diagram, with her mother, maternal grandfather, and maternal aunts all showing features of the condition. Her older brother is affected but her two young nieces (daughters of her affected brother) both show early signs. Genetic testing confirms a heterozygous pathogenic mutation in COL5A1 on chromosome 9q34.3. Which of the following best characterizes the inheritance pattern marked **A** that explains the transmission of this condition through her family?