Leber hereditary optic neuropathy (LHON) is the most extensively studied mitochondrial disease, with the majority of the cases being caused by one of three primary mitochondrial DNA (mtDNA) mutations. Incomplete disease penetrance and gender bias are two features of LHON and indicate involvement of additional genetic or environmental factors in the pathogenesis of the disorder. Haplogroups J, K, and H have been shown to influence the clinical expression of LHON in subjects harboring primary mutations in European families. However, whether mtDNA haplogroups would affect the penetrance of LHON in East Asian families has not been evaluated yet. By studying the penetrance of LHON in 1859 individuals from 182 Chinese families (including one from Cambodia) with the m.11778G-->A mutation, we found that haplogroup M7b1'2 significantly increases the risk of visual loss, whereas M8a has a protective effect. Analyses of the complete mtDNA sequences from LHON families with m.11778G-->A narrow the association of disease expression to m.12811T-->C (Y159H) in the NADH dehydrogenase 5 gene (MT-ND5) in haplogroup M7b1'2 and suggest that the specific combination of amino acid changes (A20T-T53I) in the ATP synthase 6 protein (MT-ATP6) caused by m.8584G-->A and m.8684C-->T might account for the beneficial background effect of M8a. Protein secondary-structure prediction for the MT-ATP6 with the two M8a-specific amino acid changes further supported our inferences. These findings will assist in further understanding the pathogenesis of LHON and guide future genetic counseling in East Asian patients with m.11778G-->A.

Retinitis pigmentosa (RP) is the most common and highly heterogeneous form of hereditary retinal degeneration. This study was to identify mutations in the 60 genes that were known to be associated with RP in 157 unrelated Chinese families with RP. Genomic DNA from probands was initially analyzed by whole exome sequencing. Sanger sequencing was used to confirm potential candidate variants affecting the encoded residues in the 60 genes, including heterozygous variants from genes that are related to autosomal dominant RP, homozygous or compound heterozygous variants from genes that are related to autosomal recessive RP, and hemizygous variants from genes that are related to X-linked RP. Synonymous and intronic variants were also examined to confirm whether they could affect splicing. A total of 244 candidate variants were detected by exome sequencing. Sanger sequencing confirmed 240 variants out of the 244 candidates. Informatics and segregation analyses suggested 110 potential pathogenic mutations in 28 out of the 60 genes involving 79 of the 157 (50%) families, including 31 (39%, 31/79) families with heterozygous mutations in autosomal dominant genes, 37 (47%, 37/79) families with homozygous (9) or compound heterozygous (28) mutations in autosomal recessive genes, and 11 (14%, 11/79) families with hemizygous mutations in X-linked genes. Of the 110 identified variants, 74 (67%) were novel. The genetic defects in approximately half of the 157 studies families were detected by exome sequencing. A comprehensive analysis of the 60 known genes not only expanded the mutation spectrum and frequency of the 60 genes in Chinese patients with RP, but also provided an overview of the molecular etiology of RP in Chinese patients. The analysis of the known genes also supplied the foundation and clues for discovering novel causative RP genes.

We report the synthesis and characterization of two hexapole [7]helicenes (H7Hs). Single crystal X-ray diffraction unambiguously confirms the molecular structure. H7H absorbs light, with distinct Cotton effect, from ultraviolet to the near-infrared (λ = 618 nm). Cyclic voltammetry reveals nine reversible redox states, consecutively from -2 to +6. These chiroptical and electronic properties of H7H are inaccessible from helicene's small homologues.

BackgroundLeber congenital amaurosis (LCA) is the earliest onset and most severe form of hereditary retinal dystrophy. So far, full spectrum of variations in the 15 genes known to cause LCA has not been systemically evaluated in East Asians. Therefore, we performed comprehensive detection of variants in these 15 genes in 87 unrelated Han Chinese patients with LCA.Methodology/Principal FindingsThe 51 most frequently mutated exons and introns in the 15 genes were selected for an initial scan using cycle sequencing. All the remaining exons in 11 of the 15 genes were subsequently sequenced. Fifty-three different variants were identified in 44 of the 87 patients (50.6%), involving 78 of the 88 alleles (11 homozygous and 56 heterozygous variants). Of the 53 variants, 35 (66%) were novel pathogenic mutations. In these Chinese patients, variants in GUCY2D are the most common cause of LCA (16.1% cases), followed by CRB1 (11.5%), RPGRIP1 (8%), RPE65 (5.7%), SPATA7 (4.6%), CEP290 (4.6%), CRX (3.4%), LCA5 (2.3%), MERTK (2.3%), AIPL1 (1.1%), and RDH12 (1.1%). This differs from the variation spectrum described in other populations. An initial scan of 55 of 215 PCR amplicons, including 214 exons and 1 intron, detected 83.3% (65/78) of the mutant alleles ultimately found in these 87 patients. In addition, sequencing only 9 exons would detect over 50% of the identified variants and require less than 5% of the labor and cost of comprehensive sequencing for all exons.Conclusions/SignificanceOur results suggest that specific difference in the variation spectrum found in LCA patients from the Han Chinese and other populations are related by ethnicity. Sequencing exons in order of decreasing risk is a cost-effective way to identify causative mutations responsible for LCA, especially in the context of genetic counseling for individual patients in a clinical setting.

Our results provide additional evidence to support the idea that mutation in LRPAP1 is associated with high myopia. Further studies are expected to evaluate the pathogenicity of the variants in CTSH, LEPREL1, ZNF644, SLC39A5, and SCO2.