Two American teams, one from Boston and the other from New York, have compared their points of view on the thorny question of whether or not to treat so-called “presymptomatic” subjects carrying 4 or more copies of the SMN2 gene. This question is all the more important as newborn screening for SMA is very advanced in the USA. From these exchanges, it appears that :
- A significant number of these children will become symptomatic at some point in their development,
- standardisation and reliability of the measurement of the number of copies of the SMN2 gene are necessary, as the variations are so great (including within the same laboratory),
- the borderline between presymptomatic and symptomatic states is tenuous, especially for paediatricians who are less expert in the disease.
As for the choice of treatment, and in the absence of controlled comparative trials between the three approved innovative therapies, it is still difficult to decide.
