Objective: To estimate at the national level the overall and disease-specific incidence of inborn errors of metabolism not mass screened at birth. Study design: Prospective nonconcurrent study (1985-1997) on patients 0 to 17 years of age, diagnosed in 23 Italian pediatric reference centers. Results: Cases (n = 1935) were recruited representing an incidence of 1:3707 live births for ∼200 diseases. In the last 5 years the incidence was 1:2758, reflecting improved diagnostic facilities, better coverage, increased medical awareness, and newly discovered diseases. In this period, the most frequent classes of diseases were lysosomal storage disease, 1:8275; disorders of carbohydrate metabolism, 1:19,532; organic acidopathies, 1:21,422; and primary lactic acidemias, 1:27,106. The most frequent individual diseases were Gaucher type I, 1:40,247; glycogenosis type 1a, 1:57,746; methylmalonic acidurias, 1:61,775; and ornithine transcarbamylase deficiency, 1:69,904. The incidence of diseases potentially identifiable with the use of a new neonatal mass screening technique is 1:6200. Of surviving patients, 11% reached adulthood by the end of the study. Conclusions: Inborn errors of metabolism constitute a highly heterogeneous category of rare diseases, representing a relevant cause of morbidity and mortality in childhood. This study quantifies the minimum size of the disease burden, providing useful tools for public health and health policy planning.
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health