A genome-wide association study yields five novel thyroid cancer risk loci

The great majority of thyroid cancers are of the non-medullary type. Here we report findings from a genome-wide association study of non-medullary thyroid cancer, including in total 3,001 patients and 287,550 controls from five study groups of European descent. Our results yield five novel loci (all with P_combined<3 × 10⁻⁸): 1q42.2 (rs12129938 in PCNXL2), 3q26.2 (rs6793295 a missense mutation in LRCC34 near TERC), 5q22.1 (rs73227498 between NREP and EPB41L4A), 10q24.33 (rs7902587 near OBFC1), and two independently associated variants at 15q22.33 (rs2289261 and rs56062135; both in SMAD3). We also confirm recently published association results from a Chinese study of a variant on 5p15.33 (rs2736100 near the TERT gene) and present a stronger association result for a moderately correlated variant (rs10069690; OR=1.20, P=3.2 × 10⁻⁷) based on our study of individuals of European ancestry. In combination, these results raise several opportunities for future studies of the pathogenesis of thyroid cancer.

Non-medullary thyroid cancers include papillary and follicular subtypes, and are the most common type of thyroid cancer. Here, the authors extend previous work by performing a large genome-wide association study and find five novel loci associated with this disease.

Reliability of stereoscopic nonmydriatic retinography for assessment of diabetic macular edema when performed by endocrinologists

BACKGROUND

Diabetic macular edema (DME) is the main cause of moderate vision loss in type 2 diabetes. Diagnosis is achieved by dilated fundus examination or by measuring retinal thickness. However, it can be identified in nonmydriatic retinography (NMR) with hard exudates as a surrogate marker or macular thickness under stereoscopic vision. To date, few studies have focused on interobserver reliability for DME with this technique.

METHODS

Fity-three type 2 diabetes patients with known diabetic retinopathy were studied. We obtained 182 pairs of stereoscopic retinographs with a nonmydriatic camera. Photographic options were 30 degrees or 45 degrees macula-centered retinal field and spontaneous or pharmacological dilation using tropicamide. An endocrinologist with a minimum of training and another with no specific training in this kind of examination diagnosed the images. DME was assumed if retinal thickness was identified within one disc diameter around the fovea.

RESULTS

The kappa index agreement between both endocrinologists for all the data was 0.16 (P = 0.02). Depending on the photographic options, all the kappa indices were below 0.25, except for the 45 degrees retinal field under spontaneous mydriasis (0.58) where the number of samples analyzed was reduced to 22.

CONCLUSIONS

In our study, endocrinologists with a low level of training did not reach a suitable level of agreement regarding the reliability of stereoscopic NMR as a technique for diagnosing DME. We feel that, as NMR can be performed by various different health providers, it would be advisable to establish generally agreed upon criteria for training staff in this technique.

Common variants on 9q22.33 and 14q13.3 predispose to thyroid cancer in European populations

In order to search for sequence variants conferring risk of thyroid cancer we conducted a genome-wide association study in 192 and 37,196 Icelandic cases and controls, respectively, followed by a replication study in individuals of European descent. Here we show that two common variants, located on 9q22.33 and 14q13.3, are associated with the disease. Overall, the strongest association signals were observed for rs965513 on 9q22.33 (OR = 1.75; P = 1.7 x 10(-27)) and rs944289 on 14q13.3 (OR = 1.37; P = 2.0 x 10(-9)). The gene nearest to the 9q22.33 locus is FOXE1 (TTF2) and NKX2-1 (TTF1) is among the genes located at the 14q13.3 locus. Both variants contribute to an increased risk of both papillary and follicular thyroid cancer. Approximately 3.7% of individuals are homozygous for both variants, and their estimated risk of thyroid cancer is 5.7-fold greater than that of noncarriers. In a study on a large sample set from the general population, both risk alleles are associated with low concentrations of thyroid stimulating hormone (TSH), and the 9q22.33 allele is associated with low concentration of thyroxin (T(4)) and high concentration of triiodothyronine (T(3)).