Research

Cilia & Ciliopathies

Cilia are microtubule-based organelles that project from nearly every vertebrate cell and mediate critical processes including motility, mechanosensation, and developmental signalling through pathways such as Hedgehog and Wnt. Ciliopathies are a clinically and genetically heterogeneous group of rare diseases caused by structural or functional defects in cilia or basal bodies, encompassing syndromes that affect multiple organ systems simultaneously.

What are ciliopathies?

The Kaplan Lab focuses on a spectrum of ciliopathy syndromes including Joubert syndrome (JBTS), Bardet-Biedl syndrome (BBS), Meckel–Gruber syndrome (MKS), and cranioectodermal dysplasia (CED). These conditions share overlapping genetic architecture — mutations in genes encoding components of the transition zone, IFT machinery, or BBSome — yet produce distinct phenotypes affecting the kidney, retina, brain, and skeleton.

Key discoveries

CILK1 / DYF-5

Identified as a novel causative gene of cranioectodermal dysplasia in a consanguineous family carrying a homozygous frameshift variant. CILK1 encodes an ICK-related kinase that phosphorylates IFT-B components and regulates cilia length. Sezer et al., Eur J Hum Genet 2025 →

WDR31 / ELMOD

Demonstrated that WDR31 displays functional redundancy with ELMOD and RP2 in regulating IFT complex integrity and recruiting the BBSome to cilia in C. elegans. Single mutants have mild defects; double mutants show severe ciliary phenotypes. Cevik et al., Life Sci Alliance 2023 →

ARL13B / ARL-13

Showed that Joubert syndrome-associated ARL13B is restricted to an Inv-like ciliary membrane subdomain by active transport and diffusion barriers, defining a ciliary compartment relevant to JBTS pathogenesis. Cevik et al., PLoS Genet 2013 →

CC2D1A

Established CC2D1A as a ciliopathy gene causing intellectual disability, heterotaxy, renal dysplasia, and abnormal CSF flow — expanding the phenotypic spectrum of transition zone-associated genes. Kim et al., Life Sci Alliance 2024 →

Approaches & model systems

C. elegans genetics CRISPR/Cas9 knock-in & knock-out Confocal & TIRF microscopy FIB-SEM ultrastructure Whole exome sequencing Patient variant analysis Biochemical pull-down assays

Why C. elegans?

Caenorhabditis elegans is uniquely suited to ciliopathy research. Its 60 ciliated sensory neurons are anatomically invariant and genetically tractable. The nematode ciliome is highly conserved with humans, CRISPR editing is rapid and inexpensive, and fluorescent reporter strains allow real-time imaging of IFT trains and ciliary membrane proteins in living animals. The lab uses C. elegans to validate variants identified from patient sequencing and to dissect gene function at single-cell resolution.

Cilia types in C. elegans sensory neurons.

Related publications

Sezer et al. 2025 — CILK1 & CED Cevik et al. 2023 — WDR31 & IFT Kim et al. 2024 — CC2D1A Cevik et al. 2013 — ARL13B