A Genome-Wide Association Study of Diabetic Kidney Disease in Subjects With Type 2 Diabetes

dentification of sequence variants robustly associated with predisposition to diabetic kidney disease (DKD) has the potential to provide insights into the pathophysiological mechanisms responsible. We conducted a genome-wide association study (GWAS) of DKD in type 2 diabetes (T2D) using eight complementary dichotomous and quantitative DKD phenotypes: the principal dichotomous analysis involved 5,717 T2D subjects, 3,345 with DKD. Promising association signals were evaluated in up to 26,827 subjects with T2D (12,710 with DKD). A combined T1D+T2D GWAS was performed using complementary data available for subjects with T1D, which, with replication samples, involved up to 40,340 subjects with diabetes (18,582 with DKD). Analysis of specific DKD phenotypes identified a novel signal near GABRR1 (rs9942471, P = 4.5 x 10(-8)) associated with microalbuminuria in European T2D case subjects. However, no replication of this signal was observed in Asian subjects with T2D or in the equivalent T1D analysis. There was only limited support, in this substantially enlarged analysis, for association at previously reported DKD signals, except for those at UMOD and PRKAG2, both associated with estimated glomerular filtration rate. We conclude that, despite challenges in addressing phenotypic heterogeneity, access to increased sample sizes will continue to provide more robust inference regarding risk variant discovery for DKD.Peer reviewe

A Novel Gene Deletion Associated With Xeroderma Pigmentosum And Type IA Growth Hormone Deficiency. 611

A 15 year old Chilean male, the product of a nonsanguineous uncle-niece marriage, has type IA GH deficiency and xeroderma pigmentosum (XP), both rare autosomal recessive disorders. Type IA growth hormone (GH) deficiency which is due to a 6.7 or 7.6 kb GH gene deletion is associated with production of antibodies in response to growth hormone therapy. XP causes freckling, xerosis and a variety of skin cancers. The underlying defect is abnormal DNA repair. Eight complementation groups A through G exist for XP. The chromosomal location of most of these genes has been identified (except for the `variant' type). None of these genes are known to map to the the GH locus on chromosome 17q22-q24. The XP in our patient is associated with skin freckling, actinic keratosis and basal cell carcinoma of the face. Fibroblast DNA repair studies following exposure to mitomycin C and ultraviolet C are compatible with`variant' XP. Molecular studies of the growth hormone gene locus show a novel deletion extending 5′ from the GH gene cluster and including the GH gene. GH deficiency and XP appear to be co-segregating in this family. One male sibling with GH deficiency died at the age of 4 years. He was not old enough to have developed XP and none of the remaining 6 brothers have GH deficiency or XP. We postulate that the unique gene deletion causing GH deficiency in this family, is also the location of a previously unmapped`variant' XP gene

Effects of oral insulin in relatives of patients with type 1 diabetes: The Diabetes Prevention Trial--Type 1

This randomized, double-masked, placebo-controlled clinical trial tested whether oral insulin administration could delay or prevent type 1 diabetes in nondiabetic relatives at risk for diabetes. We screened 103,391 first- and second-degree relatives of patients with type 1 diabetes and analyzed 97,273 samples for islet cell antibodies. A total of 3,483 were antibody positive; 2,523 underwent genetic, immunological, and metabolic staging to quantify risk of developing diabetes; 388 had a 5-year risk projection of 26-50%; and 372 (median age 10.25 years) were randomly assigned to oral insulin (7.5 mg/day) or placebo. Oral glucose tolerance tests were performed every 6 months. The median follow-up was 4.3 years, and the primary end point was diagnosis of diabetes. Diabetes was diagnosed in 44 oral insulin and 53 placebo subjects. Annualized rate of diabetes was similar in both groups: 6.4% with oral insulin and 8.2% with placebo (hazard ratio 0.764, P = 0.189). In a hypothesis-generating analysis of a subgroup with insulin autoantibody (IAA) levels confirmed (on two occasions) > or =80 nU/ml (n = 263), there was the suggestion of benefit: annualized diabetes rate 6.2% with oral insulin and 10.4% with placebo (0.566, P = 0.015). It is possible to identify individuals at high risk for type 1 diabetes and to enroll them in a large, multisite, randomized, controlled clinical trial. However, oral insulin did not delay or prevent type 1 diabetes. Further studies are needed to explore the potential role of oral insulin in delaying diabetes in relatives similar to those in the subgroup with higher IAA levels

Psychological adaptation in children with idiopathic short stature treated with growth hormone or placebo

The influence of short stature on psychological adaptation in childhood and adolescence is controversial. GH is currently used to treat children with idiopathic short stature (ISS, also known as non-GH-deficient short stature). This study represents the first double-blind, placebo-controlled trial of the effects of GH on the psychological adaptation of children and adolescents with ISS, treated with GH until adult height was attained. Sixty-eight children (53 males, 15 females), 9-16 yr old, with marked ISS (measured height or predicted adult height -2.5 SD or less) received either GH 0.074 mg/kg or placebo sc three times per week until height velocity decreased to less than 1.5 cm/yr. Parents completed the Child Behavior Checklist (CBCL) and children the Self-Perception Profile (SPP) and Silhouette Apperception Technique at baseline and annually thereafter. Baseline behavioral/emotional adjustment (CBCL) and self-concept (SPP) scores for children with ISS were within the normative ra