CRELD1, or Cysteine-Rich with EGF-Like Domains 1, is a crucial gene involved in multiple biological processes. It functions as a regulator of the calcineurin/NFAT signaling pathway, which is essential for cardiac development, immune system homeostasis, and other physiological functions [4,3]. Genetic models, such as gene knockout (KO) mouse models, have been instrumental in studying its functions.

In KO mouse models, lack of myocardial Creld1 leads to extracellular matrix remodeling, trabeculation defects, and early postnatal death due to myocardial hypoplasia, indicating its role in cardiac maturation and function [2]. In Xenopus tropicalis, creld1 knockdown results in developmental defects and increased seizure susceptibility [1]. In T-cell-specific Creld1-deficient mice, loss of Creld1 is associated with overactivation and increased apoptosis of T cells, causing a net loss of T cells with age, highlighting its role in immune system homeostasis [3].

In conclusion, Creld1 is essential for heart development, cardiac function, and immune system homeostasis. Studies using KO and other genetic models have revealed its significance in these processes. It also has implications in human diseases, such as the multisystem syndrome caused by recessive CRELD1 variants, which involve neurodevelopmental phenotypes, cardiac dysrhythmias, and frequent infections [1].