Genetic Analysis of CYP1B1 and Other Anterior Segment Dysgenesis-Associated Genes in Latvian Cohort of Primary Congenital Glaucoma

<b>Background</b>: Primary congenital glaucoma (PCG) is a rare disease with an incidence of 1 in 12,000 to 18,000 in Europeans. The scarcity of the disease and limited access to genetic testing have hindered research, particularly within the Latvian population. <b>Objectives</b>: This study aims to present the preliminary results of a molecular genetic investigation into PCG in a Latvian cohort and to compare the prevalence of gene <i>CYP1B1</i> variants with other European studies as well as to the general population in Latvia. <b>Methods</b>: Twenty probands with clinically diagnosed PCG and 36 family members enrolled in the study. Genetic testing was conducted using genomic DNA from peripheral blood using next generation sequencing (NGS) of seven selected genes: <i>CYP1B1, FOXC1, FOXE3, PXDN, PITX2, PITX3, PAX6</i>, and <i>CPAMD8</i>. Four probands had whole-genome sequencing (WGS). <b>Results</b>: All participants were of European ancestry, with no family history of PCG. Most probands were diagnosed in their first year of life, with a female to male ratio of 1:1.2 and with 80.0% of cases being unilateral. No <i>CYP1B1</i> pathogenic variants were identified in the screened subjects. However, a heterozygous missense variant c.4357C>A (p.Pro4357Thr) in the <i>PXDN</i> gene was found in one proband and one of her parents that was classified as a variant of uncertain significance. <b>Conclusions</b>: This study represents the first genetic characterization of PCG in the Latvian population. Using NGS, we identified no pathogenic variants in the <i>CYP1B1</i> gene among affected individuals. Preliminary evidence from this cohort does not support <i>CYP1B1</i> variants as a predominant cause of PCG, though larger studies are needed to confirm this observation. Comprehensive genetic screening using whole-exome or whole-genome sequencing will be essential to identify the underlying genetic etiology of PCG in Latvia.