# The CTDP1 Founder Variant in CCFDN: Insights into Pathogenesis, Phenotypic Spectrum and Therapeutic Approaches

## TL;DR

This paper reviews the genetic and clinical aspects of CCFDN syndrome, a rare disorder caused by a CTDP1 gene variant, and explores potential treatments.

## Contribution

The paper provides new insights into the molecular mechanisms and therapeutic strategies for CCFDN syndrome.

## Key findings

- The CTDP1 founder variant causes splicing defects leading to a multisystem phenotype in CCFDN syndrome.
- CCFDN exhibits variable clinical severity and diagnostic challenges due to overlapping features with other syndromes.
- Emerging therapies include antisense oligonucleotides and genome editing, though delivery and efficacy remain challenges.

## Abstract

Congenital Cataracts, Facial Dysmorphism, and Neuropathy (CCFDN) syndrome is a rare autosomal recessive disorder predominantly found among Vlax Roma populations, caused by a deep intronic founder variant in the CTDP1 gene. This review synthesizes recent advances in understanding the molecular mechanisms of CTDP1 dysfunction, highlighting its central role in transcriptional regulation, RNA splicing, DNA repair, and genome integrity. The unique splicing defect caused by the founder disease-causing variant in the Roma population results in a multisystem phenotype with early-onset neuropathy, congenital cataracts, and characteristic facial dysmorphism. Beyond its genetic homogeneity, CCFDN displays variable clinical severity and presents diagnostic challenges due to overlapping syndromic features. We discuss the emerging therapeutic landscape, focusing on antisense oligonucleotides, small molecule modulators, gene replacement, and genome or transcriptome editing strategies, while emphasizing the challenges in targeted delivery and efficacy. Ongoing insights into CTDP1’s broader biological functions and population genetics inform new directions for diagnosis, genetic counselling, and the development of effective therapies for this severe yet underrecognized disorder.