Over 7000 rare diseases have been described, collectively affecting 350 million people worldwide. Most of these conditions result from nonsense mutations, representing approximately 10% of all genetic mutations associated with human inherited diseases. Nonsense mutations convert a sense codon into a premature termination codon (PTC), leading to premature translation termination and the production of truncated, nonfunctional proteins. This results in a loss‐of‐function phenotype in many genetic disorders, contributing to the disease's severity and progression. The molecular mechanisms of PTC formation involve various genetic alterations, including single‐nucleotide changes, frameshifts, and splicing mutations. The nonsense‐mediated mRNA decay (NMD) pathway degrades mRNAs containing premature termination codons (PTCs). In contrast, 25% of PTC mRNAs, depending on the PTC position and cellular context, can evade NMD, resulting in the synthesis of truncated proteins. A termination codon during translation is essential for proper protein synthesis, and translational readthrough—a process in which the ribosome bypasses the PTC and reaches the natural stop codon—may restore some level of protein function. The effectiveness of readthrough depends on the surrounding genetic context and the type of amino acid incorporated at the PTC position. This review aims to explore the molecular characteristics of nonsense‐related diseases (NRDs), including cystic fibrosis, hemophilia, Fabry disease, choroideremia, Usher syndrome, Shwachman‐Diamond syndrome, and certain hereditary neuropathies and cancers.

Nonsense mutations in gene coding regions introduce an in‐frame premature termination codon (PTC) in the mRNA transcript, resulting in the early termination of translation and the production of a truncated, nonfunctional protein. The absence of protein expression and the consequent loss of essential cellular functions are responsible for the severe phenotypes in the so‐called genetic nonsense‐related diseases (NRDs), such as cystic fibrosis, hemophilia, Duchenne muscular dystrophy, Fabry disease, Choroideremia, Usher syndrome, Shwachman–Diamond syndrome, and even certain types of cancer. Nonsense mutations pose a significant challenge in the treatment of NRDs, as a specific approach directly addressing this genetic defect is currently unavailable. Developing new therapeutic strategies for nonsense suppression is a crucial goal of precision medicine. This review describes some of the most promising therapeutic approaches and emerging strategies for treating NRDs. It considered both the use of small molecules to interfere with molecular mechanisms related to nonsense mutations, such as translational readthrough‐inducing drugs (TRIDs) or inhibitors of the nonsense‐mediated decay (NMD) pathway, and also innovative approaches involving nucleic acids, such as gene editing, anticodon engineered‐tRNA (ACE‐tRNA), or mRNA‐based therapy. Future research should focus on refining these approaches and exploring integrated and personalized treatments to enhance therapeutic outcomes and ensure continuous improvement in the quality of care.

Nonsense mutations cause several genetic diseases such as cystic fibrosis, Duchenne muscular dystrophy, β-thalassemia, and Shwachman–Diamond syndrome. These mutations induce the formation of a premature termination codon (PTC) inside the mRNA sequence, resulting in the synthesis of truncated polypeptides. Nonsense suppression therapy mediated by translational readthrough-inducing drugs (TRIDs) is a promising approach to correct these genetic defects. TRIDs generate a ribosome miscoding of the PTC named “translational readthrough” and restore the synthesis of full-length and potentially functional proteins. The new oxadiazole-core TRIDs NV848, NV914, and NV930 (NV) showed translational readthrough activity in nonsense-related in vitro systems. In this work, the possible off-target effect of NV molecules on natural termination codons (NTCs) was investigated. Two different in vitro approaches were used to assess if the NV molecule treatment induces NTC readthrough: (1) a study of the translational-induced p53 molecular weight and functionality; (2) the evaluation of two housekeeping proteins’ (Cys-C and β2M) molecular weights. Our results showed that the treatment with NV848, NV914, or NV930 did not induce any translation alterations in both experimental systems. The data suggested that NV molecules have a specific action for the PTCs and an undetectable effect on the NTCs.

Nonsense mutations, often resulting from single-nucleotide substitutions, produce mRNA harboring a premature termination codon (PTC), which causes the premature termination of protein synthesis. This produces truncated and non-functional proteins, which cause different genetic diseases, including cystic fibrosis (CF). This work aims to investigate the ability of NV848 (N-(5-methyl-1,2,4-oxadiazol-3-yl)acetamide), a translational readthrough-inducing drug (TRID), to rescue CF transmembrane conductance regulator (CFTR) protein expression in a murine model characterized by the G542X nonsense mutation in the CFTR gene. In vitro experiments assessed the drug's stability in human hepatic metabolism, and in vivo investigations on wild-type mice allowed us to clarify the distribution of the drug to the target organs. Moreover, its efficacy in recovering the CFTR protein after chronic treatment was assessed in G542X homozygous mice. Our results provide valuable insights into the biodistribution and therapeutic attributes of NV848, representing a promising therapeutic tool for enhanced clinical outcomes in individuals affected by CF with nonsense mutations.

Nonsense mutations cause several genetic diseases such as Cystic fibrosis, Duchenne muscular dystrophy, β-thalassemia, and Shwachman-Diamond syndrome. These mutations induce the formation of a premature termination codon (PTC) inside the mRNA sequence that leads to the aberrant translation, resulting in the synthesis of truncated polypeptides. Nonsense suppression therapy mediated by translational readthrough-inducing drugs (TRIDs) is a promising approach to correct these genetic defects. TRIDs generate a ribosome miscoding of the PTC named “translational readthrough” and restore the synthesis of full-length and potentially functional protein. The new oxadiazole-core TRIDs NV848, NV914, and NV930 showed translational readthrough activity in nonsense-related in vitro systems. In this work, the possible off-target effect of NV molecules on natural termination codons (NTCs) was investigated. Two different in vitro approaches were used to assess if the NV molecules treatment induce NTCs readthrough: 1) A study of translational induced p53 molecular weight and functionality; 2) the evaluation of two housekeeping proteins (Cys-C and β2M) molecular weights. Our results showed that the treatment with NV848, NV914, or NV930 do not induce any translation alterations in both experimental systems. Data suggested that NV molecules have a specific action for the PTCs and an undetectable effect on the NTCs.

Nonsense mutations are among the genetic causes of LRBA (lipopolysaccharide-responsive beige-like anchor) deficiency, a rare autosomal-recessive immunodeficiency disorder. These mutations introduce premature stop codons, leading to the loss of LRBA protein expression. Following the recent market withdrawal of ataluren, the only approved translational readthrough-inducing drug (TRID), there is an urgent need for alternative therapeutic options. In this study, we investigated the efficacy of three 1,2,4-oxadiazole-based TRIDs—NV848, NV914, and NV930—using primary fibroblasts from a patient homozygous for the R1683X nonsense mutation. All compounds restored full-length LRBA protein with correct cytoplasmic localization, as confirmed by western blot and immunofluorescence, outperforming ataluren in readthrough efficiency. NV848 exhibited the strongest activity and uniquely increased LRBA mRNA levels, suggesting transcript stabilization. In contrast, NV930 and NV914 induced readthrough without stabilizing mRNA. Global proteomic profiling revealed minimal off-target effects for NV848, limited protein modulation by NV914, and widespread variations of 828 proteins by NV930, affecting pathways related to vesicular transport and mRNA splicing. However, network analysis revealed poor connectivity among differentially expressed proteins, with LRBA unrelated to any regulated cluster. These findings highlight the reported molecules as promising candidates for precision therapy in LRBA deficiency and shed light on the broader cellular impact of TRIDs.