# Exploratory Analysis of Candidate Gene Variants in Developmental Dysplasia of the Hip: Evidence for the Role of GDF5 rs143384

## TL;DR

This study explores genetic factors in hip development disorders and finds a possible link to a specific gene variant, though results are not statistically significant after correction.

## Contribution

The study investigates the role of specific SNPs and CNVs in DDH within the Slovak population, focusing on GDF5 rs143384.

## Key findings

- GDF5 rs143384 showed a nominally significant association with DDH before multiple testing correction.
- No significant associations were found for other SNPs or CNVs in the studied genes.
- MLPA analysis found no pathogenic copy number variations in the analyzed loci.

## Abstract

Background: Developmental dysplasia of the hip (DDH) is a common orthopedic disorder characterized by abnormal development of the hip joint, which can lead to pain, instability, and early-onset osteoarthritis if left untreated. Its etiology is multifactorial, involving both genetic and environmental factors. Methods: This study investigated the association between selected single-nucleotide polymorphisms (SNPs) related to joint and bone development and the occurrence of DDH. It assessed potential copy number variations (CNVs) in key skeletal genes using MLPA. A total of 125 individuals were examined, including 43 patients with DDH and 82 healthy controls. Six SNPs were genotyped using real-time PCR with TaqMan assays: TGFB1 (rs1800470), CX3CR1 (rs3732378, rs3732379), GDF5 (rs143384), COL1A1 (rs113647555), and MMP24 (rs12479765). Allele and genotype distributions were compared between cases and controls, and CNVs in COL1A1, COL2A1, LRP5, DKK1, FZD4, and NDP genes were analyzed using Multiplex Ligation-Dependent Probe Amplification. Results: Among the examined variants, only GDF5 rs143384 showed a nominally significant association with DDH (p = 0.040), with the A allele more common in affected individuals. However, after correcting for multiple testing, this result no longer remained significant. No significant associations were detected for TGFB1, CX3CR1, COL1A1, or MMP24. Although CX3CR1 rs3732378 allele frequencies differed slightly from international reference data, no link to DDH was confirmed. Conclusions: MLPA analysis did not identify pathogenic CNVs in the analyzed loci, which indicates that the studied genes have no association with DDH in the Slovak population. Similarly, SNPs in the studied genes yielded no significant results, apart from rs143384 in GDF5, which requires further investigation to confirm our findings.