Investigation of variants in the PITX3 and FOXE3 genes in a Brazilian Sport Horse with congenital bilateral anophthalmia

• Grant number: 25/09744-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: José Paes de Oliveira Filho
• Grantee: Pedro Barasnevicius da Silva
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Eye development in mammals is a highly complex process, and even minor disruptionscan lead to a range of congenital anomalies. Among the most common aremicrophthalmia (reduced eyeball size), anophthalmia (absence of the eyeball), andcoloboma (incomplete closure of the optic fissure). While several genes have beenimplicated in these malformations, those related to transcription factors are frequentlysuggested as potentially involved in their pathogenesis. In horses-animals oftenengaged in demanding and high-performance activities-any visual impairment cansignificantly impact their functionality. Therefore, research aimed at betterunderstanding these ocular anomalies is essential to improving the health and quality oflife of horses, particularly given the scarcity of data despite numerous reported cases. Acase of bilateral congenital absence of the ocular globes was confirmed in a BrazilianSport Horse through physical examination, ocular ultrasonography, and magneticresonance imaging of the brain. This undergraduate research project aims to standardizePCR protocols to identify the sequences of the candidate genes paired-likehomeodomain transcription factor 3 (PITX3) and forkhead box E3 (FOXE3). These twogenes have previously been associated with this anomaly in horses, as well as in otheranimal species and humans. PCRs will be standardized using DNA samples fromhealthy horses, and the resulting PCR products will then be sequenced using the Sangermethod. Subsequently, the sequences will be analysed in the DNA of the affectedanimal and compared to those deposited in public databases and to the sequencesobtained from healthy animals. Ultimately, any variants identified with pathogenicpotential may be used in population studies in future research. (AU)