Objectives To assess the feasibility of detecting new cases of heterozygous familial hypercholesterolaemia by using a nurse led genetic register. Design Case finding among relatives of patients with familial hypercholesterolaemia. Setting Two lipid clinics in central and south Manchester. Subjects 259 (137 men and 122 women) probands and 285 first degree relatives. Results Of the 200 first degree relatives tested, 121 (60%) had inherited familial hypercholesterolaemia. The newly diagnosed patients were younger than the probands and were generally detected before they had clinically overt atherosclerosis. Concentrations of serum cholesterol were, respectively, 8.4 (1.7 SD) mmol/l and 8.1 (1.9 SD) mmol/l in affected men and women and 5.6 (1.0 SD) mmol/l and 5.6 (1.1 SD) mmol/l in unaffected men and women. Screening for risk factors as recommended in recent guidelines for coronary heart disease prevention would have failed to identify most of the affected relatives in whom hypertension, diabetes mellitus, cigarette smoking, and obesity were uncommon. Conclusions By performing cholesterol tests on 200 relatives, 121 new patients with familial hypercholesterolaemia were discovered. Because 1 in 500 people in the UK are affected by this condition, to detect a similar number by population screening over 60 000 tests would be required, and only a few of these patients would have been detected had cholesterol testing been restricted to those with other risk factors for coronary heart disease. A case exists for organising a genetic register approach, linking lipid clinics nationally.

To cite this article: Harrington DJ, Siddiq S, Allford SL, Shearer MJ, Mumford AD. More on: endoplasmic reticulum loop VKORC1 substitutions cause warfarin resistance but do not diminish gamma-carboxylation of the vitamin K-dependent coagulation factors. J Thromb Haemost 2011; 9: 1093-5.See also Watzka M, Geisen C, Bevans CG, Sittinger K, Spohn G, Rost S, Seifried E, Mnller CR, Oldenburg J. Thirteen novel VKORC1 mutations associated with oral anticoagulant resistance: insights into improved patient diagnosis and treatment. J Thromb Haemost 2011; 9: 109-18.Watzka et al. [1] have recently reported the phenotype of patients with therapeutic resistance to 3-substituted-4-hydroxycoumarin oral anticoagulants (OACs) and with point mutations in VKORC1, which encodes vitamin K epoxide reductase subunit 1 (VKORC1). This study extends the repertoire of naturally occurring VKORC1 variants and provides valuable confirmation that VKORC1 is a molecular target of OACs. Watzka et al. also present a new topology model of VKORC1 and demonstrate that most mutations associated with OAC resistance predict substitutions within, or adjacent to, the VKORC1 endoplasmic reticulum (ER) loop (residues 30-79). This model also identifies the VKORC1 active site (CXXY; residues 132-135) that mediates de-epoxidation of vitamin K 2,3-epoxide (KO) to vitamin K (K) and the reduction of K to K hydroquinone (KH 2 ) and a putative 4-hydroxycoumarin binding motif (TYA; residues 138-140).Several groups have proposed that OACs inhibit VKORC1 reductase function by binding irreversibly at the VKORC1 active site to prevent the formation of transition state complexes that are formed normally during reduction of KO to K [2]. It is a plausible extension of this model to suggest that in OAC resistance, structural disruption of VKORC1 diminishes the affinity of OAC binding and thereby reduces this inhibition. Watzka et al. argue further that structural disruptions of VKORC1 sufficient to reduce OAC binding are also likely to reduce the binding of the KO transition state complexes and thereby, impair VKORC1 function. This is supported by previous data from ex vivo expression studies that indicate that most OAC-resistant VKORC1 variants showed a markedly impaired KO de-epoxidase activity compared with wild-type controls [1].However, some OAC-resistant ER-loop variants showed similar, or even increased, KO de-epoxidase function compared with wild-type controls [1]. Mutagenesis of the conserved Cys residues at 51 and 43 in VKORC1 did not diminish dithiothreitol-driven KO de-epoxidase and K reductase activities [3], although there was marked loss of both activities compared with wild-type VKORC1 when reduction was supported by thioredoxin oxidoreductase [4]. These data highlight continued uncertainty about the mechanism of OAC resistance and how structural variation in VKORC1 contributes to substrate and OAC interactions.We contribute to this debate by presenting phenotypic data from a subject with a previously unreported Ala34Pro substitution and two subjects with th...

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Preeclampsia (PE) is characterized by maternal hypertension, intrauterine growth restriction, increased cytolytic natural killer cells (cNKs), which secrete interferon gamma (IFNγ). However, the precise role of IFNγ in contributing to PE pathophysiology remains unclear. Using the Reduced Uterine Perfusion Pressure (RUPP) rat model of placental ischemia, we tested the hypothesis that neutralization of IFNγ in RUPPs will decrease placental reactive oxygen species (ROS) and improve vascular function resulting in decreased MAP and improved fetal growth. On Gestation Day (GD) 14, the RUPP procedure was performed and on GDs 15 and 18, a subset of normal pregnant rats (NP) and RUPP rats were injected with 10μg/kg of an anti rat-IFNγ monoclonal antibody. On GD18, Uterine Artery Resistance Index (UARI) was measured via Doppler Ultrasound and on GD19, mean arterial pressure (MAP) was measured, animals were sacrificed, and blood and tissues were collected for analysis. Increased MAP was observed in RUPP rats compared to NP and was reduced in RUPP+anti-IFNγ. Placental ROS was also increased in RUPP rats compared to NP and was normalized in RUPP+anti-IFNγ. Fetal and placental weights were reduced in RUPP rats, but were not improved following anti-IFNγ treatment. However, UARI was elevated in RUPP compared to NP and was reduced in RUPP+anti-IFNγ. In conclusion, we observed that IFNγ neutralization reduced MAP, UARI, and placental ROS in RUPP recipients. These data suggest that IFNγ is a potential mechanism by which cNKs in contribute to PE pathophysiology and may represent a therapeutic target to improve maternal outcomes in PE.