Neonatal screening program for inborn errors of metabolism: a retrospective study from 1978 to 1997 in Northeastern Italy

Aims. To assess the prevalence in northeastern Italy of various metabolic diseases (phenylketonuria, maple syrup urine disease, galactosemia, biotinidase deficiency and glucose-6-phosphate dehydrogenase deficiency) by routine neonatal screening and to compare our results with those reported for other European regions. Methods.Between 1978 and 1997, a total of 1,142,338 newborns (≈97.1% of total births) in northeastern Italy underwent blood ampling for phenylketonuria, maple syrup urine disease and galactosemia, by absorption of the specimens onto Guthrie cards; between 1989 and 1997, a total of 509,556 newborns were screened for biotinidase deficiency. Fur-thermore, between 1982 and 1997 a total of 605,604 newborns were screened for glucose- 6-phosphate dehydrogenase deficiency solely in the Veneto region. Results. The incidence of each disease was 1:45,690 for phenylketonuria; 1:190,390 for maple syrup urine disease; 1:40,780 for galactosemia; 1:63,690 for biotinidase deficiency and 0.24% for glucose-6-phosphate dehydrogenase deficiency. Conclusions. The incidence for phenylketonuria and biotinidase deficiency was lower than that found in previous studies conducted in northeastern Italy. Maple syrup urine dis-ease is a rare condition in this area, as it is in the rest of Europe, although cases with a lat-er onset may not be detected by early screening. The incidence of galactosemia was sim-ilar to that reported for the rest of Europe, while the incidence of glucose-6-phosphate de- hydrogenase deficiency was lower and had a variable distribution over the territory.