Harel-Yoon syndrome: the first case report from Saudi Arabia

Background: Harel-Yoon syndrome (HAYOS) is a recently described, rare neurodevelopmental disorder characterized by developmental delay, hypotonia, appendicular hypertonia, axonal neuropathy, and other variable features, such as spasticity and optic atrophy. With only a few reports in the literature, both heterozygous and homozygous mutations have been reported in ATPase Family AAA Domain Containing 3A (ATAD3A). Case Presentation: Herein, we present the first case of HAYOS in Saudi Arabia. A 3-month-old girl presented with global developmental delay, hypotonia, bilateral severe sensorineural hearing loss, and vision impairment. Brain magnetic resonance imaging showed mild brain atrophy and delayed myelination. Laboratory tests showed high serum lactate and increased urinary excretion of 3-hydroxy methyl glutaconic acid. Whole exome sequencing revealed a pathogenic heterozygous variant in ATAD3A gene (c.1726C>T; p. R576W: NM_018188.4 or c.1582C>T; p. R528W: NM_001170535.1) which is the same recurrent variant reported in patients with the dominant form of HAYOS. Conclusion: Our report provides further evidence of the clinical relevance of ATAD3A gene variant (c. 1726C>T; p. R576W) in the pathogenesis of HAYOS. The therapeutic options for HAYOS are limited to supportive measures as in other mitochondrial diseases. [JBCGenetics 2020; 3(1.000): 22-27

Neurological and extra-neurological clinical spectrum observed in pediatric patients with EMC1 gene variants identified by whole exome sequencing

Background: The endoplasmic reticulum membrane protein complex 1 (EMC1) gene encodes a subunit of the EMC with multiple alternatively spliced transcripts encoding different isoforms. Monoallelic and biallelic mutations of the EMC1 gene have been reported for cerebellar atrophy, visual impairment, psychomotor retardation, lipoid proteinosis of Urbach and Wiethe, and Alkuraya-Kucinskas syndrome. Objectives: Herein, we present whole exome sequencing results of eight Saudi pediatric patients with distinctive clinical features which revealed both monoallelic and biallelic variants in the EMC1 gene (CHR1 exon4:19568918, NM_001271429.2, c.364G>A; p.A122T), including two previously reported siblings (CHR1 exon21:19547328, NM_015047.3, c.2602G>A; p.G868R). Results: The patients presented with the neurological and extra-neurological clinical spectrum that included seizures, spastic diplegia, cognitive impairment, axial and appendicular hypotonia, dysmorphic features, joint hyper-flexibility, attention deficit hyperactivity disorder, skeletal dysplasia in addition to generalized global developmental delay, failure to thrive, speech delay, intellectual disability, and visual impairments. Furthermore, brain Magnetic resonance imaging findings were consistent with variable clinical features and revealed brain atrophy, thinning of corpus callosum, semi-lobar holoprosencephaly, white matter abnormality, diffuse paucity of the myelin within the brain parenchyma, and reduction of white matter arborization in the temporal lobes. Conclusion: In conclusion, these clinical cases highlight the importance of the EMC1 gene in disease phenotype and add up to the expanded EMC1-related phenotype. [JBCGenetics 2021; 4(2.000): 93-99

Favorable outcome of PML‐RARα short isoform and FLT3‐ITD mutation in a patient with several adverse prognostic markers: A case report

Key Clinical Message Complete molecular remission in a “variant APL” patient with short isoform of PML‐RARα and FLT3‐ITD mutation was achieved in response to ATRA and ATO plus IDA instead of standard treatment protocol. The use of FLT3 inhibitor in APL induction management is implicated to prevent differentiation syndrome and coagulopathy experienced in in patients with FLT3‐ITD. Abstract FLT3‐ITD mutations are the most common activating mutations in FLT3 gene, occurring in about 12 to 38% of acute promyelocytic leukemia cases, and are mainly associated with high white blood cell counts and poor clinical outcomes. Here, we present a case of APL variant with adverse prognostic features who showed short isoform [bcr3] of PML‐RARα and FLT3‐ITD mutation at diagnosis. The patient received all‐trans retinoic acid (ATRA) and arsenic trioxide (ATO) plus idarubicin (IDA) instead of standard treatment protocol, and achieved a complete morphological, cytogenetic and molecular response. However, the patient experienced differentiation syndrome, and coagulopathy that was subsequently resolved by continuous oxygen therapy, dexamethasone, and enoxaparin. The use of FLT3 inhibitor in APL induction management is implicated to prevent differentiation syndrome and coagulopathy in patients with FLT3‐ITD mutation

Proteomic identification of C/EBP-DBD multiprotein complex: JNK1 activates stem cell regulator C/EBPalpha by inhibiting its ubiquitination.

Functional inactivation of transcription factors in hematopoietic stem cell development is involved in the pathogenesis of acute myeloid leukemia (AML). Stem cell regulator C/enhancer binding protein (EBP)alpha is among such transcription factors known to be inactive in AML. This is either due to mutations or inhibition by protein-protein interactions. Here, we applied a mass spectrometry-based proteomic approach to systematically identify putative co-activator proteins interacting with the DNA-binding domain (DBD) of C/EBP transcription factors. In our proteomic screen, we identified c-Jun N-terminal kinase (JNK) 1 among others such as PAK6, MADP-1, calmodulin-like skin proteins and ZNF45 as proteins interacting with DBD of C/EBPs from nuclear extract of myelomonocytic U937 cells. We show that kinase JNK1 physically interacts with DBD of C/EBP alpha in vitro and in vivo. Furthermore, we show that active JNK1 inhibits ubiquitination of C/EBP alpha possibly by phosphorylating in its DBD. Consequently, JNK1 prolongs C/EBP alpha protein half-life leading to its enhanced transactivation and DNA-binding capacity. In certain AML patients, however, the JNK1 mRNA expression and its kinase activity is decreased which suggests a possible reason for C/EBP alpha inactivation in AML. Thus, we report the first proteomic screen of C/EBP-interacting proteins, which identifies JNK1 as positive regulator of C/EBP alpha

Synthesis and Selective Anticancer Activity of Organochalcogen Based Redox Catalysts

Many tumor cells exhibit a disturbed intracellular redox state resulting in higher levels of reactive oxygen species (ROS). As these contribute to tumor initiation and sustenance, catalytic redox agents combining significant atctivity with substrate specificity promise high activity andselectivity L. Must oxidatively stressed malignant cells. We describe here the design and synthesis of novel organochalcogen based redox sensor/effector catalysts. Their selective anticancer activity at submicromolar and low micromolar concentrations was established here in a range of tumor entities in various biological systems including cell lines, primary tumor cell cultures, and animal models. In the B-cell derived chronic lymphocytic leukemia (CLL), for instance, such compounds preferentially induce apoptosis in the cancer cells while peripheral blood mononuclear cells (PBMC) from healthy donors and the subset of normal 13-cells remain largely unaffected. In support of the concept of sensor/effector based ROS amplification, we are able to demonstrate that underlying this selective activity against CI.I. cells are pre-existing, elevated ROS levels in the leukemic cells compared to their nonmalignant counterparts. Furthermore, the catalysts act in concert with certain chemotherapeutic drugs in several carcinoma cell lines to decrease cell proliferation while showing no such interactions in normal cells. Overall, the high efficacy and selectivity of. (redox) catalytic sensor/effector compounds warrant further, extensive testing toward transfer into the clinical arena

Cell-cycle regulator E2F1 and microRNA-223 comprise an autoregulatory negative feedback loop in acute myeloid leukemia

Transcription factor CCAAT enhancer binding protein α (C/EBPα) is essential for granulopoiesis and its function is deregulated in leukemia. Inhibition of E2F1, the master regulator of cell-cycle progression, by C/EBPα is pivotal for granulopoiesis. Recent studies show microRNA-223 (miR-223), a transcriptional target of C/EBPα, as a critical player during granulopoiesis. In this report, we demonstrate that during granulopoiesis microRNA-223 targets E2F1. E2F1 protein was up-regulated in miR-223 null mice. We show that miR-223 blocks cell-cycle progression in myeloid cells. miR-223 is down-regulated in different subtypes of acute myeloid leukemia (AML). We further show that E2F1 binds to the miR-223 promoter in AML blast cells and inhibits miR-223 transcription, suggesting that E2F1 is a transcriptional repressor of the miR-223 gene in AML. Our study supports a molecular network involving miR-223, C/EBPα, and E2F1 as major components of the granulocyte differentiation program, which is deregulated in AML