The value of screening tests in children with neurofibromatosis type 1 (NF1).

Neurofibromatosis type 1 (NF1) is one of the most prevalent rare diseases. Whilst penetrance is complete by adulthood, its expressivity is extremely variable with potential multi-systemic complications. Although NF1 is diagnosed clinically, molecular analysis has a part to play in the screening of atypical forms and in genetic counselling. The screening of complications is primarily based on a full annual clinical examination and an ophthalmological examination. Targeted paraclinical examinations will be carried out when clinical signs appear (neurological, ophthalmological, cutaneous, endocrinological, orthopaedic and cardiovascular, etc.). The implementation of routine paraclinical examinations, which are stressful for families, expensive and sometimes invasive (MRI under general anaesthetic), is only of minor interest and does not lead to any change in treatment if the child is asymptomatic. Part of the consultation should focus on evaluation of psychomotor development and learning difficulties, which are common features of this condition (50%), and impact the child's quality of life.