Frontotemporal Dementia (FTD) is the second most prevalent form of early-onset dementia, following Alzheimer’s disease (AD). This condition is distinguished by the selective degeneration of the frontal and temporal lobes, resulting in personality and behavioral changes, language impairments, and executive dysfunction. Approximately 40%-50% of FTD cases have a familial component, with known causative genes including MAPT, FUS, and TARDBP. Of these, MAPT is the earliest discovered and most frequently implicated in FTD. Mutations in the MAPT gene are detectable in roughly 30% of familial FTD cases ^[1]. The tau protein, a microtubule-associated protein encoded by MAPT, is primarily localized to neuronal axons and plays a critical role in microtubule stability and assembly. By binding to microtubules, the tau protein helps to maintain neuronal cell shape. Mutations in MAPT can promote tau aggregation, leading to pathological tau protein accumulation and death of glutamatergic cortical neurons ^[2]. Additionally, certain MAPT mutations can affect pre-mRNA exon splicing, altering the ratio of 3R to 4R tau protein isoforms and increasing the relative production of 4R-tau protein, which is more prone to fibril formation ^[3-4]. Therapies targeting the MAPT gene primarily consist of small-molecule drugs and monoclonal antibodies, with indications including AD and FTD. Transgenic mice are frequently used in the drug development process, and the utilization of humanized animal models can facilitate the translation of promising treatments into clinical trials ^[5-9]. This strain is a humanized mouse model in which the endogenous mouse Mapt gene has been replaced with its human counterpart, including the 3’UTR region. This model can be utilized to study various neurodegenerative diseases, such as FTD and AD. This model is commonly named htau. In addition, based on the independently developed TurboKnockout fusion BAC recombination technology, Cyagen can also generate hot mutation models based on this strain and provide customized services for specific mutations to meet the experimental needs in pharmacology and other fields.

The IL23A gene encodes the p19 subunit, a component of interleukin-23 (IL-23), which forms a heterodimer with the p40 subunit (encoded by IL12B) to generate the functional IL-23 cytokine ^[1]. Primarily expressed by activated dendritic cells, macrophages, and monocytes, IL-23 signals through the IL-23 receptor (IL-23R) complex, activating the JAK-STAT pathway to promote Th17 cell differentiation and maintain IL-17 production. This process drives inflammatory responses and mucosal immunity against extracellular pathogens ^[1-2]. . Genetic polymorphisms within IL23A are strongly associated with autoimmune and inflammatory diseases, including psoriasis, Crohn's disease, and inflammatory bowel disease, due to dysregulated Th17 activity and chronic inflammation ^[1-2]. Monoclonal antibodies targeting IL-23, such as risankizumab and guselkumab, selectively block the p19 subunit, demonstrating therapeutic efficacy in psoriasis and inflammatory bowel diseases by suppressing pathogenic IL-17/Th17 pathways ^[3]. Also, monoclonal antibodies targeting IL-12B, such as ustekinumab, are clinically utilized for the treatment of moderate to severe psoriasis and Crohn's disease ^[4]. While IL-23 plays a role in protective immunity, its overactivation contributes to tissue damage in autoimmune settings, highlighting its dual function in immune regulation and disease pathogenesis ^[1-5]. TNF-like ligand 1A (TL1A), also known as TNF superfamily member 15 (TNFSF15), is a member of the tumor necrosis factor (TNF) family encoded by the TNFSF15 gene in humans. TL1A acts as a ligand for death receptor 3 (DR3) and decoy receptor 3 (DcR3), providing a stimulatory signal for downstream pathways. It regulates the proliferation, activation, and apoptosis of effector cells, as well as cytokine and chemokine production. TL1A is expressed in various immune cells, including monocytes, macrophages, dendritic cells, and T cells, as well as in non-immune cells such as synovial fibroblasts and endothelial cells. It plays a crucial role in modulating immune responses by promoting the differentiation and survival of T cells, particularly Th17 cells involved in inflammatory processes ^[6]. TL1A enhances IL-2 responses in anti-CD3/CD28-stimulated T cells and synergizes with IL-12 and IL-18 to augment IFN-γ release in human T and NK cells, biasing T cell differentiation toward a Th1 phenotype ^[7]. Dysregulation of TL1A expression is implicated in autoimmune diseases, including inflammatory bowel disease (IBD), rheumatoid arthritis (RA), primary biliary cholangitis (PBC), systemic lupus erythematosus (SLE), and ankylosing spondylitis (AS) ^[6]. TL1A has emerged as a promising therapeutic target, with ongoing research focused on developing monoclonal antibodies and other biologics to neutralize TL1A and reduce inflammation in autoimmune disorders. Clinical trial results suggest that TL1A inhibition can be used in the treatment of various autoimmune diseases, particularly IBD ^[8-10]. B6-hIL23A/hIL12B/hTL1A mouse is a triple-gene humanized model for IL23A, IL12B, and TNFSF15, generated by crossing B6-hIL23A&hIL12B mice (Catalog No.: C001620) with B6-hTL1A (TNFSF15) mice (Catalog No.: C001603). This model serves as a valuable tool for researching immune-related diseases, applicable to studies on immune response regulation and autoimmune diseases. It provides a robust preclinical research platform for the screening, development, and safety evaluation of drugs targeting IL23A/IL12B/TL1A.

The Transferrin receptor (TFRC) gene encodes Transferrin Receptor 1 (TFR1), a protein that is expressed at low levels in most normal cells but shows increased expression in highly proliferative cells, such as basal epidermal cells, intestinal epithelium, and certain activated immune cells. Brain capillary endothelial cells, which constitute the blood-brain barrier (BBB), also express this receptor at high levels ^[1]. TFR1 plays a critical role in maintaining iron metabolism and homeostasis by facilitating receptor-mediated endocytosis of iron-bound transferrin (Tf) via Tf cycling, thereby promoting iron uptake ^[2]. Cellular iron deficiency can lead to apoptosis, while cellular transformation requires substantial iron to sustain proliferation, with iron overload contributing to tumor progression. The high expression of TFR1 in many tumors makes it a potential tumor marker, offering a target for therapies to inhibit tumor growth and metastasis ^[1]. Moreover, TFR1 is implicated in anemia and iron metabolism disorders. Studies have shown that elevated TFR1 expression in cardiomyocytes is associated with exacerbated inflammation in myocarditis patients ^[3]. Various clinical drugs targeting TFR1 are currently under development, including antisense oligonucleotides (ASOs), antibody-drug conjugates (ADCs), and antibody-oligonucleotide conjugates, applicable to diseases such as cancer, anemia, and neurodegenerative disorders. Research indicates that enhancing antibody transport across the blood-brain barrier via TFR1, by forming specific bispecific antibodies with anti-β-amyloid antibodies, can improve therapeutic outcomes in Alzheimer's patients ^[4-5]. As research progresses, TFR1 is expected to become an effective clinical target for multiple diseases and a synergistic target for drug delivery across the blood-brain barrier (BBB). Parkinson's disease (PD) is a neurodegenerative disease with a high prevalence mainly in the middle-aged and elderly population. It is the second most common neurodegenerative disease after Alzheimer's disease (AD). The main clinical symptoms include resting tremors, limb stiffness, bradykinesia, loss of voluntary movement, etc. The typical pathological process of PD is the formation of Lewy bodies (LB) in the central nervous system (CNS), which results in the gradual death and loss of dopaminergic neurons, leading to the disease ^[6-7]. The main components of Lewy bodies are insoluble aggregates of abnormal α-synuclein (α-syn), and the SNCA gene, which encodes α-synuclein, is one of the key causative genes in Parkinson's disease. Mutations in this gene cause overexpression of α-syn, leading to the formation of Lewy bodies, ultimately leading to PD ^[8]. In addition, SNCA mutations are also associated with diseases such as dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). B6-huTFRC/huSNCA(3'UTR) mice are a dual-gene humanized model generated by crossing B6-huTFRC mice (Catalog No.: C001860) with B6-hSNCA (3'UTR) mice (Catalog No.: C001698). This model can be used for research on neurodegenerative diseases such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), as well as iron metabolism disorders and tumorigenesis and development. It is also applicable for the development of TFRC/SNCA-targeted drugs.

Duchenne Muscular Dystrophy (DMD) is a severe, progressive, and disabling X-linked recessive genetic disorder characterized primarily by muscle atrophy. This disease leads to motor impairments, eventually requiring assisted ventilation, and often results in premature death. The primary cause of DMD is mutations in the DMD gene, which encodes the dystrophin protein. These mutations lead to a reduction or absence of dystrophin in muscle tissue, resulting in muscle atrophy and related complications ^[1]. The lack of dystrophin leads to the breakdown of the dystrophin-associated protein complex (DAPC) within the muscle membrane, disrupting the interaction between actin and the extracellular matrix, making the muscles more susceptible to damage. This susceptibility results in the gradual loss of muscle tissue and function, potentially leading to cardiomyopathy ^[2]. Researchers have identified thousands of different DMD gene mutations in patients with DMD. Deletion mutations account for approximately 60%–70%, while duplication mutations account for 5%–15%. These mutations are primarily concentrated in hotspot regions of the DMD gene, specifically between exons 45-55 (47%) and exons 3-9 (7%) ^[1]. Currently, gene therapy approaches for Duchenne Muscular Dystrophy (DMD) primarily include exon skipping and AAV supplementation, as well as emerging gene editing techniques like CRISPR. The exon skipping strategy involves using antisense oligonucleotide (ASO) drugs to bind to specific sequences of pre-mRNA, skipping the mutated exon and restoring the open reading frame (ORF) integrity, thus producing a truncated but partially functional dystrophin protein. Several ASO drugs targeting the DMD gene have been approved, such as Eteplirsen (targeting exon 51), Golodirsen (targeting exon 53), and Casimersen (targeting exon 45) developed by Sarepta, and Viltolarsen (targeting exon 53) developed by Nippon Shinyaku. Since most ASO and CRISPR-based gene editing therapies target the human DMD gene, humanizing mouse genes helps accelerate clinical applications for DMD therapies, considering the genetic differences between animals and humans. The B6-hDMD (E49-53)*Del E50 mouse is a humanized model of the Dmd gene, in which the genomic sequences corresponding to exons 49–53 and their flanking regions in the mouse Dmd gene have been replaced with the corresponding human DMD gene sequences, followed by knock-out of exon 50 in the human DMD gene within the mouse genome. This model is suitable for research on Duchenne muscular dystrophy. In addition, based on the independently developed TurboKnockout fusion BAC recombination technology, Cyagen provides other humanized models such as [hE49-53], [hE44-45, c.6438+2 T to A], [hE8-30], covering most popular research areas and offering customized services based on different mutation needs.

Inhibin βE subunit (INHBE) is a member of the transforming growth factor-β (TGF-β) superfamily, highly specifically expressed in liver cells. The precursor protein of INHBE generates the inhibin β subunit after proteolytic processing. This protein is associated with various cellular processes, including cell proliferation, apoptosis, immune response, and hormone secretion. During the development of obesity and diabetes, the expression of INHBE protein inhibits the proliferation and growth of relevant cells in the pancreas and liver. Research has found a positive correlation between INHBE expression in the liver and insulin resistance and body mass index (BMI), suggesting that INHBE may be a liver factor in altering systemic metabolic status under conditions of obesity-related insulin resistance ^[1]. The studies conducted by Alnylam Pharmaceuticals and the Regeneron Genetics Center (RGC), respectively, revealed the close relationship between INHBE and fat regulation. The research demonstrated that rare loss-of-function variants in INHBE may protect the liver from the impact of inflammation, abnormal blood lipids, and type 2 diabetes by promoting healthy fat storage. Patients carrying such mutations exhibit more normal fat distribution, significantly reduced abdominal fat, improved metabolic conditions, and a decreased risk of cardiovascular diseases and type 2 diabetes ^[2-4]. These findings suggest that INHBE is a liver-specific negative regulator of fat storage. Inhibiting the expression of INHBE genes and proteins may be a potential strategy for treating metabolic disorders related to improper fat distribution and storage. Consequently, several small nucleic acid pharmaceutical companies, including Alnylam Pharmaceuticals, Arrowhead Pharmaceuticals, and Wave Life Sciences, are currently developing RNA interference (RNAi) drugs targeting INHBE to treat conditions such as obesity ^[5-7]. RNAi drugs primarily include small interfering RNA (siRNA) and antisense oligonucleotides (ASO). siRNA targets and degrades specific mRNA, while ASO binds to the target mRNA, preventing its translation or inducing its degradation, thereby inhibiting the expression of the target gene. Considering the genetic differences between humans and animals, humanizing mouse genes can accelerate the clinical development of RNAi therapies targeting human INHBE. This strain is a mouse Inhbe gene humanized model and can be used to study therapies targeting INHBE for obesity. The homozygous B6-huINHBE mice are viable and fertile. In addition, based on the independently developed TurboKnockout fusion BAC recombination technology, Cyagen can also generate hot mutation models based on this strain and provide customized services for specific mutations to meet the experimental needs in pharmacology and other fields.

Interleukin 17A (IL-17A) is a signature cytokine of the T helper 17 (Th17) subset of CD4+ T cells and one of the six members (IL-17A~IL-17F) of the IL-17 family. IL-17A is primarily produced by Th17 cells and can also be produced by other immune cells under certain conditions, including CD8+ T cells, γδT cells, natural killer T (NKT) cells, monocytes, neutrophils, and microglia ^[1]. IL-17A mediates downstream pathways that induce the production of inflammatory molecules, chemokines, antimicrobial peptides, and remodeling proteins, which have important effects on host defense, cell transport, immune regulation, and tissue repair, especially in inducing innate immune defense. In healthy skin, commensal microorganisms induce the production of IL-17A to provide antifungal protection. When the skin barrier is damaged, IL-17A promotes epithelial cell proliferation and can clear pathogenic factors, promoting tissue repair and wound healing ^[2]. IL-17A usually protects the body when it is acutely injured, but when a wound requires long-term healing and becomes a chronic injury, the role of IL-17A may transform into wound erosion or excessive proliferation, ultimately leading to loss of function ^[3]. IL-17A plays a key role in various infectious diseases, inflammations, autoimmune diseases, and cancers. Its high expression level is associated with chronic inflammatory diseases such as rheumatoid arthritis, psoriasis, and multiple sclerosis. Lung injury caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is largely the result of the promotion of inflammatory reactions by cytokines such as IL-17A. Dysregulation of IL-17 signaling promotes pathogenic inflammation. IL-17A has a pathogenic role in mediating the important inflammatory pathway of psoriasis. The IL-23/Th17/IL-17A pathway is a key link in its pathogenesis, and inhibiting the expression of IL-17A can effectively alleviate psoriasis ^[4]. IL-17A is also associated with the course of ankylosing spondylitis (AS), and IL-17A inhibitors can effectively treat AS ^[5]. In addition, studies have shown that IL-17A is involved in the pathogenesis of neurodegenerative diseases in the central nervous system, and its expression level is related to the severity and progression of the disease ^[3]. The IL17F gene, located on chromosome 6p12.2, is primarily expressed by activated T cells, particularly Th17 cells, as well as other immune cells like γδ T cells and some innate immune cells ^[6]. The gene encodes the interleukin-17F (IL-17F) cytokine, a disulfide-linked homodimer protein that shares significant sequence homology with IL-17A ^[7]. Functionally, IL-17F is a pro-inflammatory cytokine that binds to the IL-17RA/RC receptor complex, triggering downstream signaling pathways involving Act1 and TRAF6, leading to the induction of various cytokines (like IL-6, IL-8, GM-CSF) and chemokines, which contribute to neutrophil recruitment and inflammation in barrier tissues such as the skin, lungs, and gut ^[8]. Elevated levels or dysregulation of IL-17F have been implicated in the pathogenesis of several autoimmune and inflammatory diseases, including psoriasis, rheumatoid arthritis, inflammatory bowel disease (like Crohn's disease and ulcerative colitis), and potentially Sjögren's syndrome, highlighting its role in chronic inflammatory processes ^[7-9]. The B6-huIL17A/huIL17F mouse is a dual-gene humanized model constructed by gene-editing technology. Based on the B6-hIL-17A mouse (catalog number: C001510), the sequences from the ATG start codon to the TGA stop codon of the endogenous mouse Il17f gene were replaced with the sequences from the ATG start codon to the TAA stop codon of the human IL17F gene. This model can be used for research on the pathogenesis of various chronic inflammatory diseases, such as rheumatoid arthritis (RA), psoriasis, multiple sclerosis, and inflammatory bowel diseases (IBD) and the related therapeutic drugs, as well as for the development of IL17A/IL17F-targeted drugs.

The FGFR1 gene provides instructions for the synthesis of the fibroblast growth factor receptor 1, a member of the receptor tyrosine kinase (RTK) family. This protein is characterized by an extracellular region with three immunoglobulin-like domains for ligand binding, a single transmembrane segment, and an intracellular tyrosine kinase domain that triggers downstream signaling cascades like the MAPK/ERK and PI3K/AKT pathways. FGFR1 is widely expressed across diverse tissues, with particularly high levels in the developing mesoderm, skeletal system, and the central nervous system, where it is essential for the migration of gonadotropin-releasing hormone (GnRH) neurons and olfactory bulb development ^[1]. Functionally, it acts as a master regulator of cell proliferation, differentiation, and survival, playing a pivotal role in embryonic limb induction and adult tissue homeostasis ^[2]. Mutations or chromosomal aberrations in FGFR1 are linked to a diverse array of diseases: gain-of-function mutations cause craniosynostosis syndromes like Pfeiffer and Jackson-Weiss syndromes, while loss-of-function variants lead to Kallmann syndrome (characterized by delayed puberty and an absent sense of smell) ^[3]. Additionally, FGFR1 gene amplifications and rearrangements are significant oncogenic drivers in various cancers, including squamous cell lung cancer, certain breast cancers, and 8p11 myeloproliferative syndrome ^[4]. The B6-huFGFR1 mouse is a humanized model constructed through gene-editing technology, in which the mouse Fgfr1 endogenous extracellular domain genomic DNA is replaced with the human FGFR1 extracellular domain genomic DNA. This model can be used for research on craniosynostosis syndromes, Kallmann syndrome, and various cancers, as well as for screening, development, and preclinical evaluation of FGFR1-targeted therapeutics.

The IL15 gene encodes a pleiotropic four-α-helix bundle cytokine known as Interleukin-15 (IL-15), which is essential for the development, survival, and activation of immune cells, particularly Natural Killer (NK) cells and memory CD8+ T cells. Unlike many cytokines, IL-15 is primarily regulated at the post-transcriptional and translational levels rather than just transcriptionally, and it is uniquely delivered to target cells through trans-presentation, where it is shuttled to the cell surface bound to its high-affinity receptor, IL-15Rα ^[1]. The protein is widely expressed across a variety of tissues, including the placenta, skeletal muscle, kidney, lung, and heart, and is produced by both hematopoietic cells (such as monocytes, macrophages, and dendritic cells) and non-hematopoietic cells (such as epithelial cells and fibroblasts) ^[2]. Functionally, IL-15 triggers the JAK/STAT (specifically JAK1/3 and STAT3/5) and PI3K/AKT/mTOR signaling pathways to promote cellular proliferation and inhibit apoptosis by upregulating anti-apoptotic factors like BCL2 ^[3]. Because of its potent inflammatory effects, dysregulation of the IL15 gene is implicated in several pathologies: over-expression is strongly associated with autoimmune diseases like Celiac disease, Rheumatoid Arthritis, and Multiple Sclerosis, as well as certain malignancies like Adult T-cell Leukemia, while its deficiency can lead to severe immunodeficiency or impaired response to viral infections ^[4]. The B6-huIL15 mouse is a humanized model constructed through gene-editing technology, in which the region from partial intron 4 to TGA stop codon of mouse Il15 is replaced with the region from partial intron 4 to TGA stop codon of human IL15. This model can be used for research on autoimmune diseases like Celiac disease, Rheumatoid Arthritis, and Multiple Sclerosis, as well as certain malignancies like Adult T-cell Leukemia. Furthermore, it serves as a platform for the screening, development, and preclinical evaluation of IL15-targeted therapeutics.

Retinitis pigmentosa (RP) is a hereditary retinal disease with a global prevalence of approximately 1:5000-1:3000. RP is highly clinically and genetically heterogeneous, with mutations in the rhodopsin (RHO) gene causing approximately 25% of dominant RP ^[1]. The rhodopsin encoded by the RHO gene is closely associated with visual light transduction and GPCR downstream signals. Rhodopsin is essential for the transmission of light signals in the process of vision formation. Most RHO mutations lead to high levels of rhodopsin expression in photoreceptor cells, causing many mutant proteins to be abnormally located and aggregated in cells. This results in the apoptosis of photoreceptor cells, which cannot perform normal light signal transduction functions. Additionally, mutations in the RHO gene are associated with congenital stationary night blindness (CSNB) ^[2-6]. Current gene therapy targeting the RHO gene to treat retinitis pigmentosa includes ASO, CRISPR, and others. Applying fully humanized animal models will promote the further development of RHO-related potential therapies in clinical trials ^[7-12]. This strain is a mouse Rho gene humanized model, in which the endogenous mouse Rho gene is replaced by the human RHO gene carrying a P23H mutation to express human retinal proteins in mice. Therefore, the abnormal protein encoded by the human gene was expressed in mice, resulting in abnormal retinal appearance and function and visual defects in this model. Based on the self-developed technological innovation of TurboKnockout fusion BAC recombination, Cyagen can also provide customized services for different point mutations to meet the needs of a wide range of R&D personnel regarding the pharmacodynamics of retinitis pigmentosa (RP) and other preclinical needs. Mutations in the RHO gene can lead to rhodopsin-mediated autosomal dominant retinitis pigmentosa (RHO-adRP). In 25% of autosomal dominant inherited RP (adRP) cases, there are over 150 different RHO gene mutations. Notably, the P23H mutation is one of the most prevalent, accounting for 10% of adRP cases ^[2]. Previous studies have shown that mice carrying the heterozygous human RHO P23H mutation exhibit retinopathy and progressive retinal degeneration similar to the patient's disease process, which could be used for visual signaling and retinitis pigmentosa (RP) studies ^[3]. B6-hRHO-P23H homozygous mice develop the disease earlier and have a more severe phenotype than heterozygous mice. Considering the uncertainty of growth and survival of homozygous mice due to late blindness, it is recommended to use B6-hRHO-P23H heterozygous mice for experiments. However, homozygous mice may also be selected for research according to specific experimental needs.

Retinitis pigmentosa (RP) is a hereditary retinal disease with a global prevalence of approximately 1:5000-1:3000. RP is highly clinically and genetically heterogeneous, with mutations in the rhodopsin (RHO) gene causing approximately 25% of dominant RP ^[1]. The rhodopsin encoded by the RHO gene is closely associated with visual light transduction and GPCR downstream signals. Rhodopsin is essential for the transmission of light signals in the process of vision formation. Most RHO mutations lead to high levels of rhodopsin expression in photoreceptor cells, causing many mutant proteins to be abnormally located and aggregated in cells. This results in the apoptosis of photoreceptor cells, which cannot perform normal light signal transduction functions. Additionally, mutations in the RHO gene are associated with congenital stationary night blindness (CSNB) ^[2-6]. Current gene therapy targeting the RHO gene to treat retinitis pigmentosa includes ASO, CRISPR, and others. Applying fully humanized animal models will promote the further development of RHO-related potential therapies in clinical trials ^[7-12]. This strain is a humanized model of the Rho gene with a heterozygous P23H mutation. It is obtained by mating homozygous B6J-hRHO mice (Catalog Number: C001396) with homozygous B6-hRHO-P23H mice (Catalog Number: C001495). In this model, the mouse Rho gene is replaced by the human RHO gene carrying the pathogenic mutation (P23H) and the human RHO gene without the mutation, respectively. The abnormal protein encoded by the mutant human gene is expressed in the mice. Therefore, the model exhibits abnormalities in the appearance and function of the retina, as well as visual defects. In addition, based on the technological innovation of TurboKnockout combined with BAC recombination developed independently, Cyagen Biosciences can also provide customized services for different point mutations based on B6-hRHO humanized mice to meet the experimental needs related to retinitis pigmentosa (RP) diseases. Mutations in the RHO gene are a major cause of RHO-mediated autosomal dominant retinitis pigmentosa (RHO-adRP). In 25% of autosomal dominant RP (adRP) cases, over 150 different RHO gene mutants have been identified. The P23H mutation is one of the most common causes of autosomal dominant retinitis pigmentosa, accounting for approximately 10% of adRP cases ^[2]. Previous studies have demonstrated that heterozygous mice carrying this mutation exhibit retinal pathology and progressive retinal degeneration similar to the disease progression in patients ^[3], making them valuable for studying visual signal transduction and retinitis pigmentosa (RP). Homozygous mice develop the disease earlier and have more severe phenotypes compared to heterozygous mice. Considering the uncertainty of the growth status and survival period of homozygous mice due to blindness in the later stage, it is generally recommended to use heterozygous mice (B6-hRHO*P23H/hRHO, Catalog Number: C001517) for experiments.