Ptchd3, or patched domain containing 3, is a gene with a conserved patched domain, potentially functioning as a membrane receptor for the hedgehog ligand [1,2,4]. It was previously identified as a male germ-cell specific gene, and its protein product is present on the surface of mouse, rat, and human sperm [1,2,4]. The Hedgehog signaling pathway, in which Ptchd3 may be involved, is crucial for various biological processes such as pattern formation, cell fate determination, proliferation, and differentiation [4].

Using a Ptchd3 knockout mouse model, studies found that Ptchd3 knockout mice were born and lived normally, with no change in male fertility and sperm production. Also, the expression levels of several hedgehog signaling genes were not affected in mutant testis, indicating that Ptchd3 is a non-essential gene in mouse development and spermatogenesis [1,2]. In human studies, homozygous deletions of PTCHD3 were found in some individuals without ASD or any other overt abnormal phenotype, suggesting that PTCHD3 may be a non-essential gene in some humans [3].

In conclusion, through model-based research, Ptchd3 appears to be non-essential in mouse development and spermatogenesis and may also be non-essential in some humans. The Ptchd3 knockout mouse models have contributed to understanding its non-essential role in these biological processes, and further research on PTCHD3 in humans may help clarify its role in normal biology and potential disease associations [1,2,3].