Genetic Testing of Korean Familial Hypercholesterolemia Using Whole-Exome Sequencing

Familial hypercholesterolemia (FH) is a genetic disorder with an increased risk of early-onset coronary artery disease. Although some clinically diagnosed FH cases are caused by mutations in LDLR, APOB, or PCSK9, mutation detection rates and profiles can vary across ethnic groups. In this study, we aimed to provide insight into the spectrum of FH-causing mutations in Koreans. Among 136 patients referred for FH, 69 who met Simon Broome criteria with definite family history were enrolled. By whole-exome sequencing (WES) analysis, we confirmed that the 3 known FH-related genes accounted for genetic causes in 23 patients (33.3%). A substantial portion of the mutations (19 of 23 patients, 82.6%) resulted from 17 mutations and 2 copy number deletions in LDLR gene. Two mutations each in the APOB and PCSK9 genes were verified. Of these anomalies, two frameshift deletions in LDLR and one mutation in PCSK9 were identified as novel causative mutations. In particular, one novel mutation and copy number deletion were validated by co-segregation in their relatives. This study confirmed the utility of genetic diagnosis of FH through WES.     

Origin of Multicellular Pollen and Pollen Embryos in Cultured Anthers of Pepper (Capsicum Annuum)

Anthers of Capsicum annuum L. were cultured on Murashige and Skoog (MS) medium containing 0.1 mg l⁻¹ NAA and 0.1 mg l⁻¹ kinetin. Inoculated anthers were subjected to 31 °C and development of microspores in anthers of varying stages was observed cytologically using 4′-6-diamidino-2-phenylindol-2HCl (DAPI). Pepper was characterized by a strong asynchrony of pollen development within a single anther. Percentage of pollen at different stages changed with the culture period, and the proportion of dead pollen increased drastically from day 2 after culture. Microspores that were cultured at the late-uninucleate stage followed one of two developmental pathways. In the more common route, the first sporophytic division was asymmetric and produced what appeared to be a typical bicellular pollen. Embryogenic pollen was formed by repeated divisions of the vegetative nucleus. In the second pathway, which occurred in fewer microspores, the first division was symmetric and both nuclei divided repeatedly to form embryogenic pollen. In early-bicellular pollen, sporophytic pollen was produced through division of the vegetative nucleus. In mid-bicellular pollen, the generative nucleus may undergo division to produce two or more sperm-like nuclei. However, division of the generative nucleus alone to form the embryo was never observed. The anther stage optimal for embryo production contained a large proportion (>75%) of early-binucleate pollen. Associations were found among the percentage of early-binucleate pollen, the frequency of embryogenic multinucleate pollen, and the yield of pollen embryos.