Table 3 Severe MSN_I in 1739 children born 1980–1994, according to the origin of the impairment
1980–19841985–19891990–1994Total
N (%)Prevalence(per 1000)N (%)Prevalence(per 1000)N (%)Prevalence(per 1000)N (%)Prevalence(per 1000)
Children resident in Isere at the age of 774 118 (–)72 261 (–)71 904 (–)218 283 (–)
MSN_I497 (–)6.7587 (–)8.1655 (–)9.11739 (–)8.0
    Rare diseases129 (26)1.7154 (26.2)2.1176 (26.9)2.5459 (26.4)2.1
    Known origin
        Down syndrome66 (13.3)0.972 (12.3)1.073 (11.1)1.0211 (12.1)1.0
        Others126 (25.4)1.7137 (23.3)1.9175 (26.7)2.4438 (25.2)2.0
    Unknown origin176 (35.4)2.4224 (38.2)3.1231 (35.3)3.2631 (36.3)2.9
Total497 (100)587 (100)655 (100)1739 (100)