Possible counter effect in newborns of 1936A>G (I646V) polymorphism in the AKAP10 gene encoding A-kinase-anchoring protein 10

More evidence for widespread antagonistic pleiotropy in polymorphic disease alleles

Introduction

Many loci segregate alleles classified as "genetic diseases" due to their deleterious effects on health. However, some disease alleles have been reported to show beneficial effects under certain conditions or in certain populations. The beneficial effects of these antagonistically pleiotropic alleles may explain their continued prevalence, but the degree to which antagonistic pleiotropy is common or rare is unresolved. We surveyed the medical literature to identify examples of antagonistic pleiotropy to help determine whether antagonistic pleiotropy appears to be rare or common.

Results

We identified ten examples of loci with polymorphisms for which the presence of antagonistic pleiotropy is well supported by detailed genetic or epidemiological information in humans. One additional locus was identified for which the supporting evidence comes from animal studies. These examples complement over 20 others reported in other reviews.

Discussion

The existence of more than 30 identified antagonistically pleiotropic human disease alleles suggests that this phenomenon may be widespread. This poses important implications for both our understanding of human evolutionary genetics and our approaches to clinical treatment and disease prevention, especially therapies based on genetic modification.

Missense splice variant (g.20746A>G, p.Ile183Val) of interferon gamma receptor 1 (IFNGR1) coincidental with mycobacterial osteomyelitis - a screen of osteoarticular lesions

Previously, dominant partial interferon-gamma receptor 1 (IFN-g-R1) susceptibility to environmental mycobacteria was found with IFNGR1 deletions or premature stop. Our aim was to search for IFNGR1 variants in patients with mycobacterial osteoarticular lesions. Biopsies from the patients were examined for acid-fast bacilli, inflammatory cell infiltration, and mycobacterial niacin. Mycobacterial rRNA was analyzed using a target-amplified rRNA probe test. Peripheral-blood-leukocyte genomic DNA was isolated from 19 patients using the QIAamp DNA Mini Kit, and all IFNGR1 exons were sequenced using an ABIPRISM 3130 device. After the discovery of an exon 5 variant, a Polish newborn population sample (n = 100) was assayed for the discovered variant. Splice sites and putative amino acid interactions were analyzed. All patients tested were positive for mycobacteria; one was heterozygous for the IFNGR1 exon 5 single-nucleotide-missense substitution (g.20746A>G, p.Ile183Val). No other variant was found. The splice analysis indicated the creation of an exonic splicing silencer, and alternatively, molecular graphics indicated that the p.Ile183Val might alter beta-strand packing (loss of van der Waals contacts; Val183/Pro205), possibly altering the IFN-g-R1/IFN-g-R2 interaction. The probability of non-deleterious variant was estimated as <10%. Heterozygous IFNGR1:p.Ile183Val (frequency 0.003%) was found to be coincidental with mycobacterial osteomyelitis. The small amount of variation detected in the patients with osteoarticular lesions indicates that screens should not yet be restricted: Intronic variants should be analyzed as well as the other genes affecting Type 1 T-helper-cell-mediated immunity.

Genetic association of AKAP10 gene polymorphism with reduced risk of preterm birth

OBJECTIVE

Preterm birth (PTB) is a multifactorial complication in which genetic and environmental factors contribute to the phenotype. The AKAP10 protein encoded by AKAP10 gene has a vital role in the maintenance of myometrial quiescence and pregnancy. This study aimed to investigate whether polymorphisms in the AKAP10 gene are associated with the risk of PTB.

STUDY DESIGN

A total of 664 women (132 preterm and 532 term) with spontaneous singleton deliveries were genotyped for AKAP10 polymorphisms (rs119672, rs203462 and rs169412) using Sequenom MassARRAY platform.

RESULT

A significant association was observed between the CC and AC genotypes of AKAP10 rs169412 with reduced risk of PTB (CC: adjusted odds ratio (OR) 2.95, 95% confidence interval (CI): 1.23-7.09, P=0.016. AC: adjusted OR 3.46, 95% CI: 1.38-8.68, P=0.008), respectively. Following stratification by ethnicity, a significant association was observed between the AC and CC genotypes of rs169412 and term birth in the Malay ethnic subgroup. (CC: OR 2.9, 95% CI: 1.01-8.59, P=0.041. AC: OR 3.14, 95% CI: 1.04-9.54, P=0.043). A significant association was also observed between the CT genotypes of AKAP10 rs119672 with reduced risk of PTB deliveries (CT: OR 3.2, 95% CI: 1.06-9.76 P=0.007, TT: OR 2.8, 0.98-8.34, P =.0.015) Alternatively, there was no association between AKAP10 rs169412 and rs119672 polymorphisms with PTB in the Indians and Chinese ethnic groups.

CONCLUSION

This study indicates a significant association between the AKAP10 polymorphisms and reduced risk of PTB in the Malays. This demonstrates the potential role of AKAP10 polymorphisms in preterm complications.

Association of BMPR1A polymorphism, but not BMP4, with kidney size in full-term newborns

BACKGROUND

A correlation between renal mass and nephron number in newborns allows the use of total kidney volume at birth as a surrogate for congenital nephron number. As the bone morphogenetic protein type 4 (BMP4), and its receptor type 1A (BMPR1A, ALK3), play an important role in renal development, we hypothesized that common, functional polymorphisms in their genes might be responsible for variation in kidney size among healthy individuals.

METHODS

We recruited 179 healthy full-term newborns born to healthy women. Kidney volume was measured sonographically. Total kidney volume (TKV) was calculated as the sum of left and right kidneys, and normalized for body surface area (TKV/BSA). Genomic DNA was extracted from umbilical cord blood leukocytes, and c.455T > C (rs17563) BMP4 and c.67 + 5659A > T (rs7922846) BMPR1A genotypes were identified by PCR-RFLP.

RESULTS

TKV/BSA in newborns carrying at least one A BMPR1A allele (AA + AT) was significantly reduced by approximately 13 % as compared with TT homozygous newborns (106.7 ± 21.5 ml/m(2) vs. 122.7 ± 43.8 ml/m(2), p < 0.02). No significant differences in TKV/BSA were found among newborns with different BMP4 genotypes.

CONCLUSIONS

Results suggest that rs7922846 BMPR1A polymorphism may account for subtle variation in kidney size at birth, reflecting congenital nephron endowment.