Between July 2014 and December 2023, 21 boys and 8 girls undergoing follow-up at a paediatric cardiology centre in Shanghai were genetically diagnosed with Danon disease, at around 7 years of age for the boys and slightly later (9.4 years on average) for the girls. Nearly half had a family history of this very rare X-linked disease.
- An asymptomatic phase with elevated transaminases and/or CPK was found in 10 boys and one girl.
- The mean age of onset was 3 years in boys and 10 years in girls.
- Hypertrophic cardiomyopathy was found in 95% of the boys and 88% of the girls.
- While a third of the boys showed muscle weakness, only one girl showed muscular signs such as fatigue without weakness.
- During an average follow-up of 2.7 years, one boy died of heart failure at the age of 13, one girl died suddenly at the age of 14 and two boys had heart transplants.
- The incidence of ventricular pre-excitation syndrome seems to increase with the progression of the disease, since it was initially found in 36% of the children and 54% at the last check-up.
