After 42 month, the study will identify the responsible genes in a large proportion of patients with congenital hypothyroidism (excluding disorders organification of iodine), to establish a genotype-phenotype correlation and propose early genetic screening (through systematic newborn screening) to patients and their families. The study of the frequency of associated diseases and genetic elucidation will also provide recommendations for early treatment (possibly "preventive") from other later predictable and potentially negative repercussions associated with hypothyroidism