Research

Disease Modeling

Rare disease diagnosis is hampered by the sheer number of genetic variants of uncertain significance (VUS) discovered by next-generation sequencing. The Kaplan Lab develops and applies a systematic pipeline — combining patient genomics with functional validation in C. elegans — to resolve which variants are truly pathogenic and to understand the mechanisms by which they cause disease.


The variant-to-function pipeline

When a patient presents with a suspected ciliopathy or rare developmental syndrome, whole exome or genome sequencing identifies candidate variants. The challenge is distinguishing causative mutations from benign polymorphisms. The lab's pipeline moves from sequencing to functional answer in three stages:

1
Variant prioritisation

Candidate variants are filtered by allele frequency, conservation across species, and predicted functional impact. The lab's own ConVarT tool searches for equivalent variants in non-human model organisms to flag those with prior experimental evidence.

2
CRISPR/Cas9 modelling in C. elegans

The orthologous mutation is precisely introduced into the C. elegans genome using CRISPR/Cas9. The lab uses a PCR-based, cost-efficient screening strategy (see Resources) to confirm correct edits without sequencing every candidate.

3
Phenotypic & molecular characterisation

Edited worms are assessed for ciliary defects (dye-filling, IFT velocity, cilia morphology by confocal and electron microscopy), developmental phenotypes, and protein localisation using fluorescent reporters. Rescue experiments with wild-type and patient-variant alleles confirm pathogenicity.

Key findings

Cross-species variant matching
ConVarT, developed by the lab, enables systematic matching of human missense variants to equivalent positions in C. elegans, zebrafish, and other organisms — accelerating functional triage of VUS from patient cohorts. Pir et al., Nucleic Acids Res 2022 →
CRISPR variant validation
Applied CRISPR/Cas9 knock-in of patient-derived variants to distinguish causative from benign alleles in genes including CILK1, WDR31, and CC2D1A, establishing functional criteria for pathogenicity classification. Cevik et al., G3 2023 →

Technologies used

Whole exome sequencing CRISPR/Cas9 knock-in ConVarT variant matching C. elegans dye-filling assay IFT live imaging Fluorescent protein reporters Phenotypic rescue
Disease modeling in C. elegans

Functional screening of patient variants using C. elegans disease models.