Loss of function mutations in RP1 are responsible for retinitis pigmentosa in consanguineous familial cases.

PurposeThis study was undertaken to identify causal mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in consanguineous families.MethodsLarge consanguineous families were ascertained from the Punjab province of Pakistan. An ophthalmic examination consisting of a fundus evaluation and electroretinography (ERG) was completed, and small aliquots of blood were collected from all participating individuals. Genomic DNA was extracted from white blood cells, and a genome-wide linkage or a locus-specific exclusion analysis was completed with polymorphic short tandem repeats (STRs). Two-point logarithm of odds (LOD) scores were calculated, and all coding exons and exon-intron boundaries of RP1 were sequenced to identify the causal mutation.ResultsThe ophthalmic examination showed that affected individuals in all families manifest cardinal symptoms of RP. Genome-wide scans localized the disease phenotype to chromosome 8q, a region harboring RP1, a gene previously implicated in the pathogenesis of RP. Sanger sequencing identified a homozygous single base deletion in exon 4: c.3697delT (p.S1233Pfs22*), a single base substitution in intron 3: c.787+1G>A (p.I263Nfs8*), a 2 bp duplication in exon 2: c.551_552dupTA (p.Q185Yfs4*) and an 11,117 bp deletion that removes all three coding exons of RP1. These variations segregated with the disease phenotype within the respective families and were not present in ethnically matched control samples.ConclusionsThese results strongly suggest that these mutations in RP1 are responsible for the retinal phenotype in affected individuals of all four consanguineous families

Pathogenic mutations in TULP1 responsible for retinitis pigmentosa identified in consanguineous familial cases.

PurposeTo identify pathogenic mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in consanguineous familial cases.MethodsSeven large familial cases with multiple individuals diagnosed with retinitis pigmentosa were included in the study. Affected individuals in these families underwent ophthalmic examinations to document the symptoms and confirm the initial diagnosis. Blood samples were collected from all participating members, and genomic DNA was extracted. An exclusion analysis with microsatellite markers spanning the TULP1 locus on chromosome 6p was performed, and two-point logarithm of odds (LOD) scores were calculated. All coding exons along with the exon-intron boundaries of TULP1 were sequenced bidirectionally. We constructed a single nucleotide polymorphism (SNP) haplotype for the four familial cases harboring the K489R allele and estimated the likelihood of a founder effect.ResultsThe ophthalmic examinations of the affected individuals in these familial cases were suggestive of RP. Exclusion analyses confirmed linkage to chromosome 6p harboring TULP1 with positive two-point LOD scores. Subsequent Sanger sequencing identified the single base pair substitution in exon14, c.1466A>G (p.K489R), in four families. Additionally, we identified a two-base deletion in exon 4, c.286_287delGA (p.E96Gfs77*); a homozygous splice site variant in intron 14, c.1495+4A>C; and a novel missense variation in exon 15, c.1561C>T (p.P521S). All mutations segregated with the disease phenotype in the respective families and were absent in ethnically matched control chromosomes. Haplotype analysis suggested (p<10(-6)) that affected individuals inherited the causal mutation from a common ancestor.ConclusionsPathogenic mutations in TULP1 are responsible for the RP phenotype in seven familial cases with a common ancestral mutation responsible for the disease phenotype in four of the seven families

Short photoperiod-induced decrease of histamine H3 receptors facilitates activation of hypothalamic neurons in the Siberian Hamster

Nonhibernating seasonal mammals have adapted to temporal changes in food availability through behavioral and physiological mechanisms to store food and energy during times of predictable plenty and conserve energy during predicted shortage. Little is known, however, of the hypothalamic neuronal events that lead to a change in behavior or physiology. Here we show for the first time that a shift from long summer-like to short inter-like photoperiod, which induces physiological adaptation to winter in the Siberian hamster, including a body weight decrease of up to 30%, increases neuronal activity in the dorsomedial region of the arcuate nucleus (dmpARC) assessed by electro physiological patch-clamping recording. Increased neuronal activity in short days is dependent on a photoperiod-driven down-regulation of H3 receptor expression and can be mimicked in long-day dmpARC neurons by the application of the H3 receptor antagonist, clobenproprit. Short-day activation of dmpARC neurons results in increased c-Fos expression. Tract tracing with the trans-synaptic retrograde tracer, pseudorabies virus, delivered into adipose tissue reveals a multisynaptic neuronal sympathetic outflow from dmpARC to white adipose tissue. These data strongly suggest that increased activity of dmpARC neurons, as a consequence of down-regulation of the histamine H3 receptor, contributes to the physiological adaptation of body weight regulation in seasonal photoperiod

Effect of the H1N1 Influenza Pandemic on the Incidence of Epidemic Keratoconjunctivitis and on Hygiene Behavior: A Cross-Sectional Study

Background: EKC is transmitted chiefly by direct hand contact. It is suspected that the 2009/2010 influenza pandemic influenced hand washing. This study aims to examine the relationship between the 2009/2010 H1N1 influenza pandemic and hygiene behavior. Methods: We compared the EKC prevalence trends before, during and after the 2009/2010 influenza pandemic by using a t-test comparison of EKC sentinel surveillance. Results: During the pre-pandemic period, the incidence of EKC increased from the 21st to the 44th week each year. However, during the pandemic period in 2009, there was no epidemic peak. In the post-pandemic period, the epidemic curve was similar to that in the pre-pandemic period. Compared to the pre-pandemic period, the total number of EKC patients during the pandemic period showed a decrease of 44.9 % (t value = 27.23, p = 0.002). Comparing the pre-pandemic and pandemic periods by age group, we found there to be a significant decrease in the number of EKC patients for all age groups (24.12#t value#27.23, all P,0.05). This finding was most evident in the teenage group (62%) compared to the other age groups (decreases of 29 to 44%). Conclusions: A continuing effort should be made to educate the public on basic infection prevention behaviors in th

Reproductive Hormone-Dependent and -Independent Contributions to Developmental Changes in Kisspeptin in GnRH-Deficient Hypogonadal Mice

Kisspeptin is a potent activator of GnRH-induced gonadotropin secretion and is a proposed central regulator of pubertal onset. In mice, there is a neuroanatomical separation of two discrete kisspeptin neuronal populations, which are sexually dimorphic and are believed to make distinct contributions to reproductive physiology. Within these kisspeptin neuron populations, Kiss1 expression is directly regulated by sex hormones, thereby confounding the roles of sex differences and early activational events that drive the establishment of kisspeptin neurons. In order to better understand sex steroid hormone-dependent and -independent effects on the maturation of kisspeptin neurons, hypogonadal (hpg) mice deficient in GnRH and its downstream effectors were used to determine changes in the developmental kisspeptin expression. In hpg mice, sex differences in Kiss1 mRNA levels and kisspeptin immunoreactivity, typically present at 30 days of age, were absent in the anteroventral periventricular nucleus (AVPV). Although immunoreactive kisspeptin increased from 10 to 30 days of age to levels intermediate between wild type (WT) females and males, corresponding increases in Kiss1 mRNA were not detected. In contrast, the hpg arcuate nucleus (ARC) demonstrated a 10-fold increase in Kiss1 mRNA between 10 and 30 days in both females and males, suggesting that the ARC is a significant center for sex steroid-independent pubertal kisspeptin expression. Interestingly, the normal positive feedback response of AVPV kisspeptin neurons to estrogen observed in WT mice was lost in hpg females, suggesting that exposure to reproductive hormones during development may contribute to the establishment of the ovulatory gonadotropin surge mechanism. Overall, these studies suggest that the onset of pubertal kisspeptin expression is not dependent on reproductive hormones, but that gonadal sex steroids critically shape the hypothalamic kisspeptin neuronal subpopulations to make distinct contributions to the activation and control of the reproductive hormone cascade at the time of puberty

The PPCD1 Mouse: Characterization of a Mouse Model for Posterior Polymorphous Corneal Dystrophy and Identification of a Candidate Gene

The PPCD1 mouse, a spontaneous mutant that arose in our mouse colony, is characterized by an enlarged anterior chamber resulting from metaplasia of the corneal endothelium and blockage of the iridocorneal angle by epithelialized corneal endothelial cells. The presence of stratified multilayered corneal endothelial cells with abnormal patterns of cytokeratin expression are remarkably similar to those observed in human posterior polymorphous corneal dystrophy (PPCD) and the sporadic condition, iridocorneal endothelial syndrome. Affected eyes exhibit epithelialized corneal endothelial cells, with inappropriate cytokeratin expression and proliferation over the iridocorneal angle and posterior cornea. We have termed this the “mouse PPCD1” phenotype and mapped the mouse locus for this phenotype, designated “Ppcd1”, to a 6.1 Mbp interval on Chromosome 2, which is syntenic to the human Chromosome 20 PPCD1 interval. Inheritance of the mouse PPCD1 phenotype is autosomal dominant, with complete penetrance on the sensitive DBA/2J background and decreased penetrance on the C57BL/6J background. Comparative genome hybridization has identified a hemizygous 78 Kbp duplication in the mapped interval. The endpoints of the duplication are located in positions that disrupt the genes Csrp2bp and 6330439K17Rik and lead to duplication of the pseudogene LOC100043552. Quantitative reverse transcriptase-PCR indicates that expression levels of Csrp2bp and 6330439K17Rik are decreased in eyes of PPCD1 mice. Based on the observations of decreased gene expression levels, association with ZEB1-related pathways, and the report of corneal opacities in Csrp2bptm1a(KOMP)Wtsi heterozygotes and embryonic lethality in nulls, we postulate that duplication of the 78 Kbp segment leading to haploinsufficiency of Csrp2bp is responsible for the mouse PPCD1 phenotype. Similarly, CSRP2BP haploinsufficiency may lead to human PPCD

Replication of TCF4 through Association and Linkage Studies in Late-Onset Fuchs Endothelial Corneal Dystrophy

Fuchs endothelial corneal dystrophy (FECD) is a common, late-onset disorder of the corneal endothelium. Although progress has been made in understanding the genetic basis of FECD by studying large families in which the phenotype is transmitted in an autosomal dominant fashion, a recently reported genome-wide association study identified common alleles at a locus on chromosome 18 near TCF4 which confer susceptibility to FECD. Here, we report the findings of our independent validation study for TCF4 using the largest FECD dataset to date (450 FECD cases and 340 normal controls). Logistic regression with sex as a covariate was performed for three genetic models: dominant (DOM), additive (ADD), and recessive (REC). We found significant association with rs613872, the target marker reported by Baratz et al.(2010), for all three genetic models (DOM: P = 9.33×10−35; ADD: P = 7.48×10−30; REC: P = 5.27×10−6). To strengthen the association study, we also conducted a genome-wide linkage scan on 64 multiplex families, composed primarily of affected sibling pairs (ASPs), using both parametric and non-parametric two-point and multipoint analyses. The most significant linkage region localizes to chromosome 18 from 69.94cM to 85.29cM, with a peak multipoint HLOD = 2.5 at rs1145315 (75.58cM) under the DOM model, mapping 1.5 Mb proximal to rs613872. In summary, our study presents evidence to support the role of the intronic TCF4 single nucleotide polymorphism rs613872 in late-onset FECD through both association and linkage studies

Why Did Memetics Fail? Comparative Case Study

Although the theory of memetics appeared highly promising at the beginning, it is no longer considered a scientific theory among contemporary evolutionary scholars. This study aims to compare the genealogy of memetics with the historically more successful gene-culture coevolution theory. This comparison is made in order to determine the constraints that emerged during the internal development of the memetics theory that could bias memeticists to work on the ontology of meme units as opposed to hypotheses testing, which was adopted by the gene-culture scholars. I trace this problem back to the diachronic development of memetics to its origin in the gene-centered anti-group-selectionist argument of George C. Williams and Richard Dawkins. The strict adoption of this argument predisposed memeticists with the a priori idea that there is no evolution without discrete units of selection, which in turn, made them dependent on the principal separation of biological and memetic fitness. This separation thus prevented memeticists from accepting an adaptationist view of culture which, on the contrary, allowed gene-culture theorists to attract more scientists to test the hypotheses, creating the historical success of the gene-culture coevolution theory

Discovery of potent kisspeptin antagonists delineate physiological mechanisms of gonadotropin regulation

Neurons that produce gonadotropin-releasing hormone (GnRH) are the final common pathway by which the brain regulates reproduction. GnRH neurons are regulated by an afferent network of kisspeptin-producing neurons. Kisspeptin binds to its cognate receptor on GnRH neurons and stimulates their activity, which in turn provides an obligatory signal for GnRH secretion—thus gating down-stream events supporting reproduction. We have developed kisspeptin antagonists to facilitate the direct determination of the role of kisspeptin neurons in the neuroendocrine regulation of reproduction. In vitro and in vivo studies of analogues of kisspeptin-10 with amino substitutions have identified several potent and specific antagonists. A selected antagonist was shown to inhibit the firing of GnRH neurons in the brain of the mouse and to reduce pulsatile GnRH secretion in female pubertal monkeys; the later supporting a key role of kisspeptin in puberty onset. This analogue also inhibited the kisspeptin-induced release of luteinizing hormone (LH) in rats and mice and blocked the post-castration rise in LH in sheep, rats and mice, suggesting that kisspeptin neurons mediate the negative feedback effect of sex steroids on gonadotropin secretion in mammals. The development of kisspeptin antagonists provides a valuable tool for investigating the physiological and pathophysiological roles of kisspeptin in the regulation of reproduction and could offer a unique therapeutic agent for treating hormone-dependent disorders of reproduction, including precocious puberty, endometriosis, and metastatic prostate cancer