Neuroimaging genomics as a window into the evolution of human sulcal organization

Primate brain evolution has involved prominent expansions of the cerebral cortex, with largest effects observed in the human lineage. Such expansions were accompanied by fine-grained anatomical alterations, including increased cortical folding. However, the molecular bases of evolutionary alterations in human sulcal organization are not yet well understood. Here, we integrated data from recently completed large-scale neuroimaging genetic analyses with annotations of the human genome relevant to various periods and events in our evolutionary history. These analyses identified single-nucleotide polymorphism (SNP) heritability enrichments in fetal brain human-gained enhancer (HGE) elements for a number of sulcal structures, including the central sulcus, which is implicated in human hand dexterity. We zeroed in on a genomic region that harbors DNA variants associated with left central sulcus shape, an HGE element, and genetic loci involved in neurogenesis including ZIC4, to illustrate the value of this approach for probing the complex factors contributing to human sulcal evolution.

The shared genetic architecture and evolution of human language and musical rhythm

Rhythm and language-related traits are phenotypically correlated, but their genetic overlap is largely unknown. Here, we leveraged two large-scale genome-wide association studies performed to shed light on the shared genetics of rhythm (N=606,825) and dyslexia (N=1,138,870). Our results reveal an intricate shared genetic and neurobiological architecture, and lay groundwork for resolving longstanding debates about the potential co-evolution of human language and musical traits.

NANOGP1, a tandem duplicate of NANOG, exhibits partial functional conservation in human naïve pluripotent stem cells

Gene duplication events can drive evolution by providing genetic material for new gene functions, and they create opportunities for diverse developmental strategies to emerge between species. To study the contribution of duplicated genes to human early development, we examined the evolution and function of NANOGP1, a tandem duplicate of the transcription factor NANOG. We found that NANOGP1 and NANOG have overlapping but distinct expression profiles, with high NANOGP1 expression restricted to early epiblast cells and naïve-state pluripotent stem cells. Sequence analysis and epitope-tagging revealed that NANOGP1 is protein coding with an intact homeobox domain. The duplication that created NANOGP1 occurred earlier in primate evolution than previously thought and has been retained only in great apes, whereas Old World monkeys have disabled the gene in different ways, including homeodomain point mutations. NANOGP1 is a strong inducer of naïve pluripotency; however, unlike NANOG, it is not required to maintain the undifferentiated status of human naïve pluripotent cells. By retaining expression, sequence and partial functional conservation with its ancestral copy, NANOGP1 exemplifies how gene duplication and subfunctionalisation can contribute to transcription factor activity in human pluripotency and development.

Discovery of 42 genome-wide significant loci associated with dyslexia

Reading and writing are crucial life skills but roughly one in ten children are affected by dyslexia, which can persist into adulthood. Family studies of dyslexia suggest heritability up to 70%, yet few convincing genetic markers have been found. Here we performed a genome-wide association study of 51,800 adults self-reporting a dyslexia diagnosis and 1,087,070 controls and identified 42 independent genome-wide significant loci: 15 in genes linked to cognitive ability/educational attainment, and 27 new and potentially more specific to dyslexia. We validated 23 loci (13 new) in independent cohorts of Chinese and European ancestry. Genetic etiology of dyslexia was similar between sexes, and genetic covariance with many traits was found, including ambidexterity, but not neuroanatomical measures of language-related circuitry. Dyslexia polygenic scores explained up to 6% of variance in reading traits, and might in future contribute to earlier identification and remediation of dyslexia.

Genome-wide analyses of individual differences in quantitatively assessed reading- and language-related skills in up to 34,000 people

The use of spoken and written language is a fundamental human capacity. Individual differences in reading- and language-related skills are influenced by genetic variation, with twin-based heritability estimates of 30 to 80% depending on the trait. The genetic architecture is complex, heterogeneous, and multifactorial, but investigations of contributions of single-nucleotide polymorphisms (SNPs) were thus far underpowered. We present a multicohort genome-wide association study (GWAS) of five traits assessed individually using psychometric measures (word reading, nonword reading, spelling, phoneme awareness, and nonword repetition) in samples of 13,633 to 33,959 participants aged 5 to 26 y. We identified genome-wide significant association with word reading (rs11208009, P = 1.098 × 10-8) at a locus that has not been associated with intelligence or educational attainment. All five reading-/language-related traits showed robust SNP heritability, accounting for 13 to 26% of trait variability. Genomic structural equation modeling revealed a shared genetic factor explaining most of the variation in word/nonword reading, spelling, and phoneme awareness, which only partially overlapped with genetic variation contributing to nonword repetition, intelligence, and educational attainment. A multivariate GWAS of word/nonword reading, spelling, and phoneme awareness maximized power for follow-up investigation. Genetic correlation analysis with neuroimaging traits identified an association with the surface area of the banks of the left superior temporal sulcus, a brain region linked to the processing of spoken and written language. Heritability was enriched for genomic elements regulating gene expression in the fetal brain and in chromosomal regions that are depleted of Neanderthal variants. Together, these results provide avenues for deciphering the biological underpinnings of uniquely human traits.

Stationary Patterns in a Two-Protein Reaction-Diffusion System

Patterns formed by reaction-diffusion mechanisms are crucial for the development or sustenance of most organisms in nature. Patterns include dynamic waves, but are more often found as static distributions, such as animal skin patterns. Yet, a simplistic biological model system to reproduce and quantitatively investigate static reaction-diffusion patterns has been missing so far. Here, we demonstrate that the Escherichia coli Min system, known for its oscillatory behavior between the cell poles, is under certain conditions capable of transitioning to quasi-stationary protein distributions on membranes closely resembling Turing patterns. We systematically titrated both proteins, MinD and MinE, and found that removing all purification tags and linkers from the N-terminus of MinE was critical for static patterns to occur. At small bulk heights, dynamic patterns dominate, such as in rod-shaped microcompartments. We see implications of this work for studying pattern formation in general, but also for creating artificial gradients as downstream cues in synthetic biology applications.

Palbebral anthrax

PURPOSE

Anthrax is a rare infection transmitted to humans from animals or animal products. In cutaneous anthrax it may produce lesions of the eyelids which can lead to cicatricial ectropion.

METHODS

We examined three women and five men with anthrax of the eyelids. Intravenous penicillin G was used alone as therapy.

RESULTS

All patients presented with a localized itchy erythematous papule of the eyelid. A necrotising ulcer formed in each case, resulting in black eschar. The lesions resolved, with only mild cicatrization of the eyelid in all the patients.

CONCLUSIONS

Anthrax is primarily an infectious disease of domestic animals but it is also seen in humans. Eyelids are rarely affected but cutaneous anthrax should be considered in any patient with a painless ulcer or black eschar who has a history of exposure to animals.

Ocular findings in Sturge-Weber syndrome

PURPOSE

We reviewed the rare ocular findings of Sturge-Weber syndrome (SWS) and the results of implantation of the Ahmed valve in cases associated with glaucoma.

METHODS

Seven patients (range 18 to 52 years) diagnosed as SWS were reviewed as clinical findings over two years. An anterior chamber maintainer was placed in patients with glaucoma to maintain stable intraocular pressure and minimize the risk of intraocular hemorrhage due to sudden pressure changes during surgery, when an Ahmed valve is implanted.

RESULTS

Episcleral venous vessels were prominent in all cases. Diffuse choroidal hemangiomas were seen in three cases. Nevus of Ota was observed in only one case. Three cases had juvenile glaucoma. One also had buphthalmos. No intraocular hemorrhage or choroidal effusion was observed intraoperatively in valve-implant patients. The surgical treatment of the patients with glaucoma gave favorable outcomes.

CONCLUSIONS

Rare ocular findings such as choroidal hemangioma and nevus of Ota are sometimes seen in SWS. Drainage valve implantation, with an anterior chamber maintainer, is a good choice for treatment when surgery is done in cases with glaucoma. This method may reduce the risk of intraoperative suprachoroidal effusion and expulsive hemorrhage by stabilizing intraocular pressure within normal limits during the surgery.

Color Doppler ultrasonography in ocular Behçet's disease

PURPOSE

The aim of this prospective study was to assess the ocular hemodynamic changes in patients with Behcet's disease who had involvement of the posterior segment by color Doppler ultrasonography.

METHODS

The present study was carried out in 32 eyes of 24 patients with ocular Behcet's disease and 42 eyes of 21 persons as a healthy age-matched control group. In order to detect the hemodynamic changes in ocular Behcet's disease, peak systolic and end-diastolic velocities (PSV, EDV; cm/sec), resistive and pulsatile indices (RI, PI), and PSV/EDV ratio of central retinal artery (CRA), short posterior ciliary artery (PCA) and ophthalmic artery (OA) were determined.

RESULTS

The mean PSV and EDV (8.1+/-2.6 and 2.7+/-0.1 cm/sec, respectively) in the CRA were significantly lower in patients with Behcet's disease than in healthy controls (11.5+/-2.2 and 3.5+/-1.0 cm/sec, respectively, p<0.001). For the PCA, these values (12.7+/-4.2 and 4.3+/-1.1 cm/sec, respectively) were significantly lower in the patient group than in the control the group (18.2+/-4.2 and 6.1+/-2.5 cm/sec, respectively, p<0.001). In the patient group, a statistically significant decrease compared to the control group was detected in the mean PSV of the OA (31.8+/-8.2 and 35.8+/-0.6 cm/sec, respectively, p<0.02). However, no significant difference in the other parameters of these vessels was observed between groups.

CONCLUSIONS

These results demonstrate the presence of some circulatory changes in the flow velocities of the CRA, PCA and OA in patients with Behcet's disease when compared with control subjects.

Penetration of oral and topical ciprofloxacin into human aqueous humor

PURPOSE

This study was planned to investigate the penetration of ciprofloxacin into aqueous humor following oral and topical application as a prophylactic antimicrobial agent.

METHODS

Forty-six patients undergoing cataract surgery were randomly divided into two groups. In the first group, the patients received 500 mg oral ciprofloxacin eight hours before surgery and in the second, 5 drops of 0.3% ciprofloxacin were applied to the patients every twenty minutes, starting 100 minutes before the surgery. By paracentesis, aqueous samples were taken just before the operation so the interval between the first topical application and paracentesis was 100 minutes.

RESULTS

The mean concentration of ciprofloxacin in aqueous humor was 0.63+/-0.29 microg/ml in the first group. The concentration was 0.69+/-0.30 microg/ml in the second group. Both of these mean concentrations were higher than the levels of MIC90 of S.aureus , S. epidermidis, P. aeruginosa and Gram (-) bacteriae.

CONCLUSION

As a result, both topically and orally applied ciprofloxacin achieved a significant aqueous concentration. Each route studied might be suitable for surgical prophylaxis or treatment of infections.

Anthrax as the cause of preseptal cellulitis

Anthrax is an infectious disease caused by Bacillus anthracis. It is primarily a disease of domestic animals such as cattle, goats, and sheep; but humans can rarely be infected by contact with infected animals or contaminated animal products. Our case is a 4-year-old boy who was initially diagnosed as preseptal cellulitis, but later he showed the characteristic anthrax lesions with a black necrotic eschar. Scrapings from the necrotic tissue showed gram positive rods and culture grew Bacillus anthracis. The patient responded to intravenous administration of penicillin G, and the lesions resolved, leaving a scar on the right upper eyelid. Eyelid involvement of anthrax is rarely seen in clinical practice, but should be considered in differential diagnosis.