Stargardt-like Clinical Characteristics and Disease Course Associated with Variants in the WDR19 Gene

WDR19-associated retinopathy presenting with adult-onset Stargardt-like phenotype

BACKGROUND

Pathogenic variants in the WDR19 gene are linked to a spectrum of ciliopathies, which can present with ophthalmic symptoms. In this study, we describe the multimodal imaging findings of a patient with an adult-onset Stargardt-like phenotype associated with biallelic WDR19 variants.

METHODS

The patient underwent a comprehensive ophthalmologic evaluation, including slit-lamp examination, optical coherence tomography (OCT), fundus autofluorescence (FAF), and OCT-angiography (OCTA). Genetic testing was conducted using next-generation sequencing (NGS).

RESULTS

The patient carried the WDR19 p.(Arg477Leu) missense variant (class 3) in trans with the c.1777 + 1delG splice variant (class 4), never described before in association with a clinical phenotype. Multimodal imaging revealed bilateral areas of definitely decreased autofluorescence (DDAF), which progressively expanded over time. Additionally, bilateral thickening of the ellipsoid zone and intraretinal cysts in the left eye were observed.

CONCLUSIONS

Biallelic variants in the WDR19 gene can cause an autosomal recessive, adult-onset Stargardt-like phenotype. Ophthalmologists should consider this as possible molecular differential diagnosis when encountering atypical features on multimodal imaging in cases with negative genetic testing for ABCA4.

Dynamic Outlier Slicing Allows Broader Exploration of Adaptive Divergence: A Comparison of Individual Genome and Pool-Seq Data Linked to Humic Adaptation in Perch

How genetic variation contributes to adaptation at different environments is a central focus in evolutionary biology. However, most free-living species still lack a comprehensive understanding of the primary molecular mechanisms of adaptation. Here, we characterised the targets of selection associated with drastically different aquatic environments-humic and clear water-in the common freshwater fish, Eurasian perch (Perca fluviatilis). By using whole-genome sequencing (WGS) on a large population dataset (n = 42 populations) and analysing 873,788 SNPs, our primary aim was to uncover novel and confirm known footprints of selection. We compared individual and pooled WGS, and developed a novel approach, termed dynamic outlier slicing, to assess how the choice of outlier-calling stringency influences functional and Gene Ontology (GO) enrichment. By integrating genome-environment association (GEA) analysis with allele frequency-based approaches, we estimated composite selection signals (CSS) and identified 2679 outlier SNPs distributed across 324 genomic regions, involving 468 genes. Dynamic outlier slicing identified robust enrichment signals in five annotation categories (upstream, downstream, synonymous, 5'UTR and 3'UTR) highlighting the crucial role of regulatory elements in adaptive evolution. Furthermore, GO analyses revealed strong enrichment of molecular functions associated with gated channel activity, transmembrane transporter activity and ion channel activity, emphasising the importance of osmoregulation and ion balance maintenance. Our findings demonstrate that despite substantial random drift and divergence, WGS of high number of population pools enabled the identification of strong selection signals associated with adaptation to both humic and clear water environments, providing robust evidence of widespread adaptation. We anticipate that the dynamic outlier slicing method we developed will enable a more thorough exploration of adaptive divergence across a diverse range of species.