Changing incidence of neonatal hypermethioninaemia: implications for the detection of homocystinuria.

Hyperphenylalaninaemia of various types among three-quarters of a million neonates tested in a screening programme.

“…The method4 was based on the principles given by Guthrie and Susi5 except that after December 1974 the Guthrie cards were not autoclaved before assay. Phenylalanine was semiquantitated by reference to standard blood spots containing 60-1200 Vmol/l (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) Vmol/l (4 mg/100 ml) was accepted as a negative result provided some growth was visible around the disc on the Guthrie plate. Every positive test, no matter how small the increase in phenylalanine, was followed up until a negative screening test was obtained or a definitive diagnosis was reached.…”

Alterations in Bone Mineral Density in Marfan Syndrome and Homocystinuria

“…False negative newborn screening filter paper specimens may occur for various reasons. These include that hypermethioninemia may not manifest itself during the first few days of life [20] and may be further compounded due to infant feeding practices which lead to lower protein intake [21]. The collection of specimens for newborn screening during early infant discharge may preclude ascertainment of some cases of homocystinemia [22].…”

Homocystinuria

“…Secondly, Cruysberg et al's findings suggest the need for research into identifying suitable tests to undertake mass neonatal screening. Unfortunately, the use of hypermethioninaemia for this purpose is unreliable,6 19 and perhaps research would be better directed towards tests based on molecular genetic techniques.…”