In 1969, Dr Zatz started her work in genetic counseling in families which were carriers of neuromuscular diseases, in order to evaluate as well as to inform the risk of having offspring with a similar problem.

These children, who generally had a normal mental development but whose muscular problems were not treated, neither went to school nor underwent physical therapy.

100 children and adolescents divided into daily groups of twenty patients, besides eventual visits adding up to approximately 300 people per month.

[3] Since the beginning of her career Mayana has assisted approximately 16,000 people of families affected by genetic diseases (mostly neuromuscular problems), which is the highest number of cases registered in the world.

In the latter part of 1995, Mayana, professor Maria Rita Passos Bueno, and doctorate student Eloísa de Sá Moreira were the first scientists in the world to find one of the genes related to a dystrophy which affects the arms and legs.