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Worldwide, there is increasing acknowledgment of the importance of getting access to ancestry information. More and more countries facilitate access to this information through law changes and voluntary contact-services. In the Netherlands, the state-funded Fiom KID-DNA database was established in 2010 to facilitate information and/or contact exchange between those people who are genetically related as a result of donor-assisted conception. By the end of 2021, 846 donors and 2355 donor-conceived people are registered in the database. For 25% of the donors a link was found with one or more donor-conceived people, and 39% of the donor-conceived people were linked to a donor-profile. Fiom offers support by professionally qualified staff throughout the entire process from registration to contact to donor-conceived people, donors and their relatives. During the period of more than 10 years several challenges emerged; how does a state-funded DNA database function in the area of commercial DNA databases?; what can be learned from the continuous growing donor-conceived half-siblings networks?; how to deal with malpractices from the past and how to cope with ageing donors? [ABSTRACT FROM AUTHOR]

Results demonstrate a 4sodium/1calcium plus 1potasium stoichiometry for the retinal cone potassium-dependent sodium/calcium exchanger. High Five cells containing sodium/calcium channel proteins and deficient in two large hydrophilic loops, exhibit significant calcium-dependent rubidium uptake. The bovine sodium/calcium exchanger, however, does not show calcium-dependent rubidium uptake.

Purpose: To study the possible involvement of the rod (SLC24A1) and cone (SLC24A2) Na-Ca+K exchanger (NCKX) genes in retinal diseases., Methods: DNA was collected from unrelated patients with retinal disease, mainly from North America. A human genomic library was screened with the cone NCKX cDNA, and hybridizing clones were sequenced to determine the genomic organization of the SLC24A2 gene. The single-strand conformation polymorphism (SSCP) technique and direct sequencing were used to screen the patients' DNA for mutations in SLC24A1 and SLC24A2. The effect of selected missense changes on protein function was tested by measuring potassium-dependent Na-Ca exchange of the mutant proteins expressed in insect cells., Results: Twenty-seven novel sequence changes were found in the rod NCKX gene, 21 of which are unlikely to be pathogenic, because they did not cosegregate with the disease or did not affect conserved regions of the protein. Of the remaining six, two were frameshift mutations found in one patient each. If translated, these alleles would encode nonfunctional proteins. Three of the six possibly pathogenic mutations were missense changes located in conserved regions, and their protein functions were assayed. Only one (Ile992Thr) had a significantly low level of exchanger function, but it was found in two unrelated patients who were heterozygotes with different retinal diseases, and this mutation could not be unequivocally associated with either disease. The last of the six changes is likely to create a new splice acceptor site. The genomic organization of the cone NCKX gene was determined, and it contained 11 exons with a few splice variants. Fifteen novel sequence changes were identified in the cone exchanger gene in patients with a cone dysfunction or degeneration. Only three of these sequence changes, all missense changes found in heterozygous patients, were considered possibly pathogenic. Functional analysis showed only a slight reduction in the activity of the corresponding mutant proteins., Conclusions: Although variant alleles of the rod and cone NCKX genes were found, none could be definitively associated with a specific retinal disease. The human phenotype associated with mutant exchanger alleles remains unknown.

The past few years has seen significant progress in our understanding of the retinal rod and cone Na+/Ca2+-K+ exchanger (NCKX) genes. The human rod and cone NCKX genes were localized to chromosomes 15q22 and 9p22, respectively. In situ hybridization localized the rod and cone NCKX transcripts in both human and chicken retinas: rod NCKX transcripts were found only in the inner segments of rods, whereas cone NCKX transcripts were found in a subset of retinal ganglion cells as well as in the inner segments of cones. We identified two sets of putative transmembrane spanning segments (TM's) as the only sequence elements strongly conserved between the rod and cone NCKX cDNAs, as well as between mammalian NCKX cDNAs and NCKX cDNAs cloned from lower organisms (C. elegans and Drosophila). The two sets of TM's make up less than onethird of the rod NCKX sequence and less than half of the cone NCKX sequence. Basic cation binding properties as inferred from an analysis of 45Ca transport rates and NCKX currents were very similar for all our NCKX clones, implying that conserved residues within the two sets of TM's contain all the residues involved in cation binding and cation transport.