Molecular genetic analysis of long QT syndrome in Norway indicating a high prevalence of heterozygous mutation carriers.

Mutations in the KCNQ1, HERG, SCN5A, minK and MiRP1 genes cause long QT syndrome (LQTS), of which there are two forms: the Romano Ward syndrome and the Jervell and Lange-Nielsen syndrome. We have performed DNA sequencing of the LQTS-associated genes in 169 unrelated patients referred for genetic testing with respect to Romano Ward syndrome and in 13 unrelated patients referred for genetic testing with respect to Jervell and Lange-Nielsen syndrome. A total of 37 different mutations in the 5 genes, of which 20 were novel, were identified. Among patients with the most stringent clinical criteria of Romano Ward syndrome, a mutation was identified in 71%. Twelve of the 13 unrelated patients referred for genetic testing with respect to Jervell and Lange-Nielsen syndrome were provided with a molecular genetic diagnosis. Cascade genetic screening of 505 relatives of index patients with molecularly defined LQTS identified 251 mutation carriers. The observed penetrance was 41%. Although caution must be exerted, the prevalence of heterozygotes for mutations in the LQTS-associated genes in Norway could be in the range 1/100-1/300, based on the prevalence of patients with Jervell and Lange-Nielsen syndrome.

Patent ductus venosus does not lead to alimentary galactosaemia in preterm infants.

UNLABELLED: The aim of this study was to investigate if an open ductus venosus representing a portal-caval shunt can lead to transient "alimentary galactosaemia" in preterm infants fed human breast milk. Twenty-six preterm infants (28-34 wk of gestational age) with open ductus venosus were included. Capillary blood samples for measurement of galactose and glucose were collected before, 30 and 50 min after a meal with breast milk (range 12-23 mL/kg). Ultrasound studies of the blood flow in the ductus venosus, truncus coeliacus, superior mesenteric artery and left hepatic vein were performed before and 30 min after the meal. There was a significant rise in blood glucose after 30 and 50 min, indicating a sufficient lactose load. Galactose, however, was either not detectable or was just above the detectable limit (0.1-0.4 mmol/L), with no changes after the meal. An increased flow velocity was found in the ductus venosus and superior mesenteric artery after 30 min (p < or = 0.001) indicating increased entero-hepatic and portal-caval shunting. CONCLUSION: A patent ductus venosus does not lead to a significant hypergalactosaemia in preterm infants fed human breast milk. Thus, in respect to breast-milk feeding, this is regarded safe in healthy preterm infants even with an open ductus venosus. The increased portal-caval shunting may, however, influence the hepatic metabolism of other enterally absorbed substances.

A comparison between haematological parameters in 'capillary' and venous blood samples from hospitalized children aged 3 months to 14 years.

In 16 hospitalized children aged 3 months to 14 years EDTA-blood samples were taken simultaneously from an anticubital vein and from a finger tip. Haematological measurements were subsequently performed in an Ortho ELT 800/WS analyzer. The thrombocyte count and the red cell indices were nearly identical in the two sets of samples. The 'capillary' erythrocyte count, haematocrit and haemoglobin values exceeded those of venous blood by 2%, and the mean 'capillary' total leukocyte count by about 20%. The relative frequency of lymphocytes, granulocytes and mononuclear cells did not alter between the two sets of samples. The significant differences demonstrated may in certain clinical settings be of medical importance. Their possible explanations are discussed.