Pathogenic variants causing ABL1 malformation syndrome cluster in a myristoyl-binding pocket and increase tyrosine kinase activity

Asciminib in the treatment of chronic myeloid leukemia in chronic phase

In the evolving therapeutic landscape of chronic myeloid leukemia (CML), asciminib stands out as a critical treatment option. Its ability to bind to and allosterically modulate the myristoyl pocket of BCR::ABL1 enables asciminib to effectively overcome resistance to conventional tyrosine kinase inhibitors (TKIs). Asciminib has shown significant cytogenetic and molecular responses in heavily pretreated patients, those previously exposed to ponatinib, and treatment-naïve individuals, attributed to its pharmacological selectivity and generally favorable safety profile. Asciminib also offers a compelling alternative for patients with a history of cardiovascular events or unfavorable cardiovascular profiles. However, extended follow-up in ongoing trials is necessary for a thorough assessment of its long-term benefits. Mutations in the myristoyl pocket, such as A337V/T and I502L, along with kinase domain mutations, including F359C/I/V at the kinase-SH2 interface and M244V in the N-lobe, have demonstrated the ability to undermine asciminib effectiveness in clinical practice, highlighting the importance of mutational assessment before starting treatment. This review provides an in-depth analysis of the preclinical and clinical evidence supporting the use of asciminib, synthesizing findings from a targeted literature search of PubMed and Web of Science. Our discussion integrates insights into its mechanism of action, clinical efficacy, safety, resistance patterns, and future directions.

Dandy-Walker malformation in an individual with ABL1 variant

Dandy-Walker malformation (DWM) is often sporadic, but there are a growing number of genetic disorders that have been associated with this condition. We present a female individual with a de novo variant in ABL1, c.734A>G (p.Y245), who was diagnosed prenatally with DWM. ABL1-related neurodevelopmental disorder was recently identified but brain malformations have not been well characterized to date. We reviewed the published literature and identified one additional individual with DWM and ABL1-related disorder, which suggests a possible association with this malformation.

The molecular basis of Abelson kinase regulation by its αI-helix

Abelson tyrosine kinase (Abl) is regulated by the arrangement of its regulatory core, consisting sequentially of the SH3, SH2, and kinase (KD) domains, where an assembled or disassembled core corresponds to low or high kinase activity, respectively. It was recently established that binding of type II ATP site inhibitors, such as imatinib, generates a force from the KD N-lobe onto the SH3 domain and in consequence disassembles the core. Here, we demonstrate that the C-terminal αI-helix exerts an additional force toward the SH2 domain, which correlates both with kinase activity and type II inhibitor-induced disassembly. The αI-helix mutation E528K, which is responsible for the ABL1 malformation syndrome, strongly activates Abl by breaking a salt bridge with the KD C-lobe and thereby increasing the force onto the SH2 domain. In contrast, the allosteric inhibitor asciminib strongly reduces Abl's activity by fixating the αI-helix and reducing the force onto the SH2 domain. These observations are explained by a simple mechanical model of Abl activation involving forces from the KD N-lobe and the αI-helix onto the KD/SH2SH3 interface.

DECIPHER: Improving Genetic Diagnosis Through Dynamic Integration of Genomic and Clinical Data

DECIPHER (Database of Genomic Variation and Phenotype in Humans Using Ensembl Resources) shares candidate diagnostic variants and phenotypic data from patients with genetic disorders to facilitate research and improve the diagnosis, management, and therapy of rare diseases. The platform sits at the boundary between genomic research and the clinical community. DECIPHER aims to ensure that the most up-to-date data are made rapidly available within its interpretation interfaces to improve clinical care. Newly integrated cardiac case-control data that provide evidence of gene-disease associations and inform variant interpretation exemplify this mission. New research resources are presented in a format optimized for use by a broad range of professionals supporting the delivery of genomic medicine. The interfaces within DECIPHER integrate and contextualize variant and phenotypic data, helping to determine a robust clinico-molecular diagnosis for rare-disease patients, which combines both variant classification and clinical fit. DECIPHER supports discovery research, connecting individuals within the rare-disease community to pursue hypothesis-driven research.

The Genetics and Typical Traits of Thoracic Aortic Aneurysm and Dissection

Genetic predisposition and risk factors such as hypertension and smoking can instigate the development of thoracic aortic aneurysm (TAA), which can lead to highly lethal aortic wall dissection and/or rupture. Monogenic defects in multiple genes involved in the elastin-contractile unit and the TGFβ signaling pathway have been associated with TAA in recent years, along with several genetic modifiers and risk-conferring polymorphisms. Advances in omics technology have also provided significant insights into the processes behind aortic wall degeneration: inflammation, epigenetics, vascular smooth muscle phenotype change and depletion, reactive oxygen species generation, mitochondrial dysfunction, and angiotensin signaling dysregulation. These recent advances and findings might pave the way for a therapy that is capable of stopping and perhaps even reversing aneurysm progression.