The availability of genetic variants, together with phenotypic annotations from model organisms, facilitates comparing these variants with equivalent variants in humans. However, existing databases and search tools do not make it easy to scan for equivalent variants, namely ‘matching variants’ (MatchVars) between humans and other organisms. Therefore, we developed an integrated search engine called ConVarT (http://www.convart.org/) for matching variants between humans, mice, and Caenorhabditis elegans. ConVarT incorporates annotations (including phenotypic and pathogenic) into variants, and these previously unexploited phenotypic MatchVars from mice and C. elegans can give clues about the functional consequence of human genetic variants. Our analysis shows that many phenotypic variants in different genes from mice and C. elegans, so far, have no counterparts in humans, and thus, can be useful resources when evaluating a relationship between a new human mutation and a disease.

The availability of genetic variants, together with phenotypic annotations from model organisms, facilitates comparing these variants with equivalent variants in humans. However, existing databases and search tools do not make it easy to scan for equivalent variants, namely “orthologous variants,” between humans and other organisms. Therefore, we developed an integrated search engine called ConVarT (http://www.convart.org/) for orthologous variants between humans, mice, and C. elegans. ConVarT incorporates annotations (including phenotypic and pathogenic) into variants, and these previously unexploited phenotypic OrthoVars from mice and C. elegans can give clues about the functional consequence of human genetic variants. Our analysis shows that many phenotypic variants in different genes from mice and C. elegans, so far, have no counterparts in humans, and thus, can be useful resources when evaluating a relationship between a new human mutation and a disease.Graphical Abstract

The term ciliopathy refers to a group of over 35 rare disorders characterized by defective cilia and many overlapping clinical features, such as hydrocephalus, cerebellar vermis hypoplasia, polydactyly, and retinopathy. Even though many genes have been implicated in ciliopathies, the genetic pathogenesis in certain cases remains still undisclosed. Here, we identified a homozygous truncating variant in WDR31 in a patient with a typical ciliopathy phenotype encompassing congenital hydrocephalus, polydactyly and renal agenesis. WDR31 is an evolutionarily conserved protein that localizes to the cilium and cilia-related compartment. Analysis from zebrafish supports the role of WDR31 in regulating the cilia morphology. The CRISPR/Cas9 knock-in (p.Arg261del) C. elegans model of the patient variant (p.Arg268*) reproduced several cilia-related defects observed in wdr-31 null mutants. Mechanistic analysis from C. elegans revealed that WDR-31 functions redundantly with ELDM-1 (ELMOD protein) and RPI-2 (RP2) to regulate the IFT trafficking through controlling the cilia entry of the BBSome. This work revealed WDR31 as a new ciliopathy protein that regulates IFT and BBSome trafficking.

The term “ciliopathy” refers to a group of over 35 rare disorders characterized by defective cilia and many overlapping clinical features, such as hydrocephalus, cerebellar vermis hypoplasia, polydactyly, and retinopathy. Even though many genes have been implicated in ciliopathies, the genetic pathogenesis in certain cases remains still undisclosed. Here, we identified a homozygous truncating variant in WDR31 in a patient with a typical ciliopathy phenotype encompassing congenital hydrocephalus, polydactyly, and renal agenesis. WDR31 is an evolutionarily conserved protein that localizes to the cilium and cilia-related compartment. Analysis from zebrafish supports the role of WDR31 in regulating the cilia morphology. The CRISPR/Cas9 knock-in (p.Arg261del) C. elegans model of the patient variant (p.Arg268*) reproduced several cilia-related defects observed in wdr-31 null mutants. Mechanistic analysis from C. elegans revealed that WDR-31 functions redundantly with ELDM-1 (ELMOD protein) and RPI-2 (RP2) to regulate the IFT trafficking through controlling the cilia entry of the BBSome. This work revealed WDR31 as a new ciliopathy protein that regulates IFT and BBSome trafficking.

The correct intraflagellar transport (IFT) assembly at the ciliary base and the IFT turnaround at the ciliary tip are key for the IFT to perform its function, but we still have poor understanding about how these processes are regulated. Here, we identify WDR31 as a new ciliary protein, and analysis from zebrafish andCaenorhabditis elegansreveals the role ofWDR31in regulating the cilia morphology. We find that loss of WDR-31 together with RP-2 and ELMD-1 (the sole ortholog ELMOD1-3) results in ciliary accumulations of IFT Complex B components and KIF17 kinesin, with fewer IFT/BBSome particles traveling along cilia in both anterograde and retrograde directions, suggesting that the IFT/BBSome entry into the cilia and exit from the cilia are impacted. Furthermore, anterograde IFT in the middle segment travels at increased speed inwdr-31;rpi-2;elmd-1. Remarkably, a non-ciliary protein leaks into the cilia ofwdr-31;rpi-2;elmd-1, possibly because of IFT defects. This work reveals WDR31–RP-2–ELMD-1 as IFT and BBSome trafficking regulators.