Segregation of a novel p.(Ser270Tyr) <Emphasis Type="Italic">MAF</Emphasis> mutation and p.(Tyr56∗) <Emphasis Type="Italic">CRYGD</Emphasis> variant in a family with dominantly inherited congenital cataracts

A bilaterally blind woman, with a three generation family history of autosomal dominant congenital cataracts, variably associated with iris colobomata and microcornea, sought preconception genetic consultation. Whole-exome sequencing was performed in three affected family members, one unaffected first degree relative, and one spouse. The sequence variant c.168C>G; p.(Tyr56?) in CRYGD, previously reported as pathogenic, and a novel mutation c.809C>A; p.(Ser270Tyr) in MAF, were identified in two affected family members; the grandmother, and half-brother of the proband. The proband inherited only the MAF mutation, whereas her clinically unaffected sister had the CRYGD change. In silico analysis supported a pathogenic role of p.(Ser270Tyr) in MAF, which was absent from publicly available whole-exome datasets, and 1161 Czech individuals. The frequency of CRYGD p.(Tyr56?) in the ExAC dataset was higher than the estimated incidence of congenital cataract in the general population. Our study highlights that patients with genetically heterogeneous conditions may exhibit rare variants in more than one disease-associated gene, warranting caution with data interpretation, and supporting parallel screening of all genes known to harbour pathogenic mutations for a given phenotype. The pathogenicity of sequence variants previously reported as cataract-causing may require re-assessment in light of recently released datasets of human genomic variation.     

Invasion of the Zebra Mussel Dreissena polymorpha (Pallas, 1771) (Dreissenidae) in Lake Ladoga

Biology Bulletin - In May 2019, the invasive mollusk Dreissena polymorpha (Pallas, 1771) was found in Volkhov Bay of Lake Ladoga by means of an unmanned underwater vehicle. The age of some mollusks...     

The polygon method of the meiobenthos spatial distribution study in the littoral zone of Lake Ladoga (A case study of the northern skerry region of the Lake)

A new approach is applied in the study of the distribution of meiobenthos in the littoral zone of the skerry region of Lake Ladoga. The initial stage is the measurement of the polygon bathymetry; the study and mapping of the distribution of different sediments (taking into account their change with the increase in depth); and the distribution of macrophytes, phytobenthos, and large habitat-forming mollusks (Unionidae). The abundance, composition, and structure of meiobenthos are studied. The data make it possible to map the distribution of the community. Similar zonality in the distribution of bottom sediments and large habitatforming biota upon the transition from the water edge to the depths at the boundary of the littoral zone is found. Six main belts are revealed and described.