Shwachman-Diamond Syndrome Research Articles

Mitotic abnormalities and spindle assembly checkpoint inactivation in a cell model of Shwachman-Diamond syndrome with mutations in the Shwachman-Bodian-Diamond syndrome gene, 258+2T > C.

Hematologic abnormalities are the most common symptoms of Shwachman-Diamond syndrome (SDS). The causative gene for SDS is the Shwachman-Bodian-Diamond syndrome (SBDS) gene; however, the function of SBDS and pathogenesis of each condition in SDS are largely unknown. SBDS is known to be localized at mitotic spindles and stabilizes microtubules. Previously, we demonstrated that SBDS is ubiquitinated and subsequently degraded in the mitotic phase, thereby accelerating mitotic progression. In this study, we examined mitosis in a myeloid cell model of SDS (SDS cells). 4',6-Diamidino-2-phenylindole (DAPI)-stained chromosome observation and cell cycle analysis of nocodazole-synchronized cells revealed that the SDS cells have abnormally rapid mitosis. In addition, many lagging chromosomes and micronuclei were detected. Moreover, the phosphorylation of threonine tyrosine kinase, the crucial kinase of the spindle assembly checkpoint (SAC), was suppressed. Chromosomal instability caused by SAC dysfunction may cause a variety of clinical conditions, including hematologic tumors in patients with SDS.

Shwachman-Diamond syndrome due to biallelic EFL1 variants with complex and fatal clinical course in early infancy.

Shwachman-Diamond syndrome represents a clinically and genetically heterogeneous disorder. We report on an infant with a very severe, fatal clinical course caused by biallelic EFL1 variants: c.89A>G, p.(His30Arg), and c.2599A>G, p.(Asn867Asp). Functional analysis of patient-derived B-lymphoblastoid and SV40-transformed fibroblast cell lines suggests that the compound heterozygous EFL1 variants impaired mature ribosome formation leading to compromised protein synthesis, ultimately resulting in a severe form of Shwachman-Diamond syndrome.

Shwachman-Diamond syndrome: A case report.

Shwachman-Diamond syndrome (SDS) is a rare autosomal recessive genetic disease, the diagnosis is a big challenge for clinician, as the clinical manifestations of the disease are diverse. Here, we report a girl who diagnosed with SDS with the symptoms of recurrent fever, elevated transaminase levels, and granulocytosis. The aspects of diagnosis and treatment were discussed and a literature review was conducted. A 15-month-old girl admitted to our hospital because of recurrent fever, granulocytopenia, and elevated transaminase levels. The compound heterozygous variant of Shwachman-Bodian-Diamond syndrome c.258 + 2T > C:p.84Cfs3 and c.96C > G:p.Y32* were detected after sequencing the blood samples from the patient and her parents. Finally, she was diagnosed with SDS and she was treated with compound glycyrrhizin, granulocyte-colony stimulating factor, and antibiotic in the case of co-infection. During the follow-up, her liver function showed the level of transaminases decreased and she rarely had infection after the age of 15 months although neutropenia is still present. Patients with SDS lacks typical clinical symptoms, which presents a huge challenge for clinicians. Genetic testing techniques is playing an important role in the diagnosis of diseases. This patient without typical clinical manifestations such as exocrine pancreatic insufficiency and skeletal abnormality, we report this case aimed to strengthen the understanding of the disease.

Loss of Dnajc21 leads to cytopenia and altered nucleotide metabolism in zebrafish

Mutations in the DNAJC21 gene were recently described in Shwachman–Diamond syndrome (SDS), a bone marrow failure syndrome with high predisposition for myeloid malignancies. To study the underlying biology in hematopoiesis regulation and disease, we generated the first in vivo model of Dnajc21 deficiency using the zebrafish. Zebrafish dnajc21 mutants phenocopy key SDS patient phenotypes such as cytopenia, reduced growth, and defective protein synthesis. We show that cytopenia results from impaired hematopoietic differentiation, accumulation of DNA damage, and reduced cell proliferation. The introduction of a biallelic tp53 mutation in the dnajc21 mutants leads to the development of myelodysplastic neoplasia-like features defined by abnormal erythroid morphology and expansion of hematopoietic progenitors. Using transcriptomic and metabolomic analyses, we uncover a novel role for Dnajc21 in nucleotide metabolism. Exogenous nucleoside supplementation restores neutrophil counts, revealing an association between nucleotide imbalance and neutrophil differentiation, suggesting a novel mechanism in dnajc21-mutant SDS biology.

SBDS Gene Mutation Increases ROS Production and Causes DNA Damage as Well as Oxidation of Mitochondrial Membranes in the Murine Myeloid Cell Line 32Dcl3.

Shwachman-Diamond syndrome (SDS) is an autosomal recessive disease caused by mutation in the Shwachman-Bodian-Diamond syndrome (SBDS) gene. SDS has a variety of clinical features, including exocrine pancreatic insufficiency and hematological dysfunction. Neutropenia is the most common symptom in patients with SDS. SDS is also associated with an elevated risk of developing myelodysplastic syndromes and acute myeloid leukemia. The SBDS protein is involved in ribosome biogenesis, ribosomal RNA metabolism, stabilization of mitotic spindles and cellular stress responses, yet the function of SBDS in detail is still incompletely understood. Considering the diverse function of SBDS, the effect of SBDS seems to be different in different cells and tissues. In this study, we established myeloid cell line 32Dcl3 with a common pathogenic SBDS variant on both alleles in intron 2, 258 + 2T > C, and examined the cellular damage that resulted. We found that the protein synthesis was markedly decreased in the mutant cells. Furthermore, reactive oxygen species (ROS) production was increased, and oxidation of the mitochondrial membrane lipids and DNA damage were induced. These findings provide new insights into the cellular and molecular pathology caused by SBDS deficiency in myeloid cells.

From Challenge to Opportunity: How Shwachman-Diamond Syndrome Became a Promising Target for Therapy Development.

From Challenge to Opportunity: How Shwachman-Diamond Syndrome Became a Promising Target for Therapy Development.

Aberrant early hematopoietic progenitor formation marks the onset of hematopoietic defects in Shwachman-Diamond syndrome.

Shwachman-Diamond syndrome (SDS) is an inherited bone marrow failure disorder that often presents at infancy. Progress has been made in revealing causal mutated genes (SBDS and others), ribosome defects, and hematopoietic aberrations in SDS. However, the mechanism underlying the hematopoietic failure remained unknown, and treatment options are limited. Herein, we investigated the onset of SDS embryonic hematopoietic impairments. We generated SDS and control human-derived induced pluripotent stem cells (iPSCs). SDS iPSCs recapitulated the SDS hematological phenotype. Detailed stepwise evaluation of definitive hematopoiesis revealed defects that started at the early emerging hematopoietic progenitor (EHP) stage after mesoderm and hemogenicendothelium were normally induced. Hematopoietic potential of EHPs was markedly reduced, and the introduction of SBDS in SDS iPSCs improved colony formation. Transcriptome analysis revealed reduced expression of ribosome and oxidative phosphorylation-related genes in undifferentiated and differentiated iPSCs. However, certain pathways (e.g., DNA replication) and genes (e.g., CHCHD2) were exclusively or more severely dysregulated in EHPs compared with earlier and later stages. To our knowledge, this study offers for the first time an insight into the embryonic onset of human hematopoietic defects in an inherited bone marrow failure syndrome and reveals cellular and molecular aberrations at critical stages of hematopoietic development toward EHPs.

Clinical Profile of Adults with Inherited Bone Marrow Failure Syndromes: Results of an Ambispective Clinical Single-Center Study

BACKGROUND. Inherited bone marrow failure syndromes (IBMFS) is a heterogenous group of rare genetically determined diseases with variable hematologic and nonhematologic manifestations. The implementation of highly specific methods of genetic diagnosis advanced the understanding of IBMFS and allowed its application also beyond pediatrics. That presupposes an awareness of clinical features and reference points for recognizing IBMFS in adults. AIM. To describe the clinical profile of adult IBMFS patients. MATERIALS & METHODS. This ambispective single-center study enrolled 35 patients (10 women and 25 men) with IBMFS. Patients were aged 18–51 years (median 26 years). The following IBMFS were identified: congenital dyskeratosis (n = 10; 28 %), Diamond-Blackfan anemia (n = 9; 26 %), Fanconi anemia (n = 7; 20 %), GATA2 deficiency (n = 3; 8 %), Shwachman-Diamond syndrome (n = 1; 3 %), GATA2 deficiency (n = 1; 3 %), amegakaryocytic thrombocytopenia (n = 1; 3 %), bone marrow failure syndrome type 3 (n = 1; 3 %), severe congenital neutropenia (n = 1; 3 %), bone marrow failure with SAMD9 mutation (n = 1; 3 %). These diseases were analyzed in terms of hematologic and nonhematologic manifestations as well as main diagnosis stages and factors that contribute to recognizing IBMFS. RESULTS. Monolinear cytopenia, bilinear cytopenia, and pancytopenia were identified at hematologic onset in 18 (52 %), 6 (17 %), and 11 (31 %) patients, respectively. The median age of patients by hematologic onset was 15 years (range 0–43 years), in 14 (40 %) patients cytopenia was newly diagnosed at the age of > 18 years. In 23 (63 %) patients hypocellular bone marrow was reported, 7 (20 %) and 5 (14 %) patients had pure red cell aplasia and multilineage myelodysplasia, respectively. Chromosomal aberrations were identified in 2 patients. Paroxysmal nocturnal hemoglobinuria clone was detected in none of 27 examined patients. In 12 (34 %) patients, the criteria for non-severe aplastic anemia were met. Temporary partial or complete spontaneous hematologic recovery was observed in 6 (17 %) patients. Abnormalities with partial or complete organ dysfunctions were identified in 14 patients, whereas all patients showed minor congenital defects. All 7 Fanconi anemia patients and 9 out of 10 congenital dyskeratosis patients demonstrated organ damage specific to these diseases. Family history predominantly showing malignant neoplasms in relatives was reported in 15 (43 %) patients. Initial hematological examination yielded suspect of IBMFS in 12 (34 %) patients with the median time to diagnosis of 6 months. In 23 (66 %) patients, hematologic defects with cytopenia were erroneously accounted for by various acquired diseases, which led to a delayed correct diagnosis (median 7 years). The key factors in suspecting IBMFS were organ abnormalities and positive family history. The IBMFS diagnosis was verified by the next-generation sequencing (NGS) in 29 (83 %) patients and by other specific methods in 4 (11 %) patients. In 2 patients, the diagnosis was established on the basis of complete clinical criteria alone. CONCLUSION. IBMFS is a matter of current concern and a difficult-to-recognize clinical challenge in adult hematology patients. Differential diagnosis of acquired and congenital bone marrow failure needs to be performed irrespective of patient’s age. A detailed physical examination of patients, family history, and critical analysis of clinical profile and disease course allow for early suspicion of IBMFS. Suspected IBMFS is an indication for referral of patients to specialized centers and performing genetic diagnostics including NGS.

ДИФФЕРЕНЦИАЛЬНАЯ ДИАГНОСТИКА ПРИОБРЕТЕННОЙ АПЛАСТИЧЕСКОЙ АНЕМИИ У ДЕТЕЙ: АНАЛИЗ ДАННЫХ РЕГИСТРОВОГО ИССЛЕДОВАНИЯ

Acquired aplastic anemia (AA) is still the diagnosis of exclusion. The purpose of the research was to identify clinical and laboratory signs that do not correspond to acquired AA allowing to diagnose other diseases accompanied by cytopenia. Materials and methods used: Authors represent the results of diagnostic search in pediatric patients (0 to 18 y/o) with a suspected diagnosis of acquired AA who underwent remote diagnosis in the laboratories of the National Scientific and Practical Center for Pediatric Hematology, Oncology and Immunology named after Dmitry Rogachev (Moscow, Russia) as part of the Register Study in Sep. 1, 2017-May 1, 2022. Results: in retrospective analysis of 523 children records, 104 (20%) patients had other diagnoses. In 29 (27.9%) patients were diagnosed with inherited bone marrow failure syndromes (IBMFS), in 11 (10.6%) with myelodysplastic syndrome, in 11 (10.6%) with deficiency anemia, in 10 (9.6%) with congenital unspecified AA, in 7 (6.7%) with immune cytopenia, in 7 (6.7%) with inborn defects of immunity, in 6 (5.8%) with secondary AA, in 6 (5.8%) with acute leukemia, in 2 (1.9%) with paroxysmal nocturnal hemoglobinuria and in 15 (14.4%) cases with other unspecified diseases. Fanconi anemia (n=15/29 patients) was the most common disease in the IBMFS group; this group had also included: dyskeratosis congenita (n=9), Schwachman-Diamond syndrome (n=2), amegakaryocytic thrombocytopenia (n=2), Diamond-Blackfan anemia in combination with congenital neutropenia (n=1). Conclusion: differential diagnosis of acquired AA can be difficult though it is undoubtedly must-do for successful treatment. Verification of other alternative diseases, including genetically determined syndromes, contributes to the choice of optimal patient management tactics.

Lethal Complications and Complex Genotypes in Shwachman Diamond Syndrome: Report of a Family with Recurrent Neonatal Deaths and a Case-Based Brief Review of the Literature.

Shwachman Diamond Syndrome (SDS) is a multi-system disease characterized by exocrine pancreatic insufficiency with malabsorption, infantile neutropenia and aplastic anemia. Life-threatening complications include progression to acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS), critical deep-tissue infections and asphyxiating thoracic dystrophy. In most patients, SDS results from biallelic pathogenic variants in the SBDS gene, different combinations of which contribute to heterogenous clinical presentations. Null variants are not well tolerated, supporting the theory that the loss of SBDS expression is likely lethal in both mice and humans. A novel complex genotype (SBDS:c.[242C>G;258+2T>C];[460-1G>A]/WFS1:c.[2327A>T];[1371G>T]) was detected in a family with recurrent neonatal deaths. A female neonate died three hours after birth with hemolytic anemia, and a male neonate with severe anemia, thrombocytopenia and neutropenia succumbed on day 40 after Staphylococcus epidermidis infection. A subsequent review of the literature focused on fatal complications, complex SBDS genotypes and/or unusual clinical presentations and disclosed rare cases, of which some had unexpected combinations of genetic and clinical findings. The impact of pathogenic variants and associated phenotypes is discussed in the context of data sharing towards expanding scientific expert networks, consolidating knowledge and advancing an understanding of novel underlying genotypes and complex phenotypes, facilitating informed clinical decisions and disease management.

Overexpression of human SAMD9 inhibits protein translation and alters MYC signaling resulting in cell cycle arrest

Inherited bone marrow failure syndromes often result from pathogenic mutations in genes that are important for ribosome function, namely, Diamond-Blackfan anemia, Shwachman-Diamond syndrome, and dyskeratosis congenita. Germline mutations in SAMD9 are a frequent genetic lesion resulting in an inherited bone marrow failure syndrome with monosomy 7; some patients have severe multisystem syndromes that include myelodysplasia. The association of germline SAMD9 mutations and bone marrow failure is clear; however, to date, there is no reliable method to predict whether a novel SAMD9 mutation is pathogenic unless it is accompanied by an obvious family history and/or clinical syndrome. The difficulty with pathogenicity prediction is, in part, due to the incomplete understanding of the biological functions of SAMD9. We used a SAMD9-targeted, inducible CRISPRa system and RNA sequencing to better understand the global transcriptional changes that result from transcriptional manipulation of SAMD9. Supporting recent discoveries that SAMD9 acts as a ACNase specific for phenylalanine tRNA (tRNA-Phe), we confirmed with crosslinking and solid-phase purification that SAMD9 is an RNA binding protein and analyzed how overexpression of tRNA-Phe may reverse transcriptomic changes caused by SAMD9 activation. Our data show that overexpression of SAMD9 from the endogenous locus results in decreased cell proliferation, cell cycle progression, and global protein translation. When SAMD9 contains a gain-of-function mutation (p.E1136Q), these functional phenotypes are exacerbated but only partially rescued with tRNA-Phe overexpression, suggesting additional molecular actions of SAMD9. Additionally, we demonstrate that gene expression pathways important for ribosome biogenesis and MYC signaling are the most significantly impacted by SAMD9 overexpression.

Dissecting thrombus-directed chemotaxis and random movement in neutrophil near-thrombus motion in flow chambers

BackgroundThromboinflammation is caused by mutual activation of platelets and neutrophils. The site of thromboinflammation is determined by chemoattracting agents release by endothelium, immune cells, and platelets. Impaired neutrophil chemotaxis contributes to the pathogenesis of Shwachman-Diamond syndrome (SDS). In this hereditary disorder, neutrophils are known to have aberrant chemoattractant-induced F-actin properties. Here, we aim to determine whether neutrophil chemotaxis could be analyzed using our previously developed ex vivo assay of the neutrophils crawling among the growing thrombi.MethodsAdult and pediatric healthy donors, alongside with pediatric patients with SDS, were recruited for the study. Thrombus formation and granulocyte movement in hirudinated whole blood were visualized by fluorescent microscopy in fibrillar collagen-coated parallel-plate flow chambers. Alternatively, fibrinogen, fibronectin, vWF, or single tumor cells immobilized on coverslips were used. A computational model of chemokine distribution in flow chamber with a virtual neutrophil moving in it was used to analyze the observed data.ResultsThe movement of healthy donor neutrophils predominantly occurred in the direction and vicinity of thrombi grown on collagen or around tumor cells. For SDS patients or on coatings other than collagen, the movement was characterized by randomness and significantly reduced velocities. Increase in wall shear rates to 300–500 1/s led to an increase in the proportion of rolling neutrophils. A stochastic algorithm simulating leucocyte chemotaxis movement in the calculated chemoattractant field could reproduce the experimental trajectories of moving neutrophils for 72% of cells.ConclusionsIn samples from healthy donors, but not SDS patients, neutrophils move in the direction of large, chemoattractant-releasing platelet thrombi growing on collagen.

Integrated proteogenomic analysis for inherited bone marrow failure syndrome.

Recent advances in in-depth data-independent acquisition proteomic analysis have enabled comprehensive quantitative analysis of >10,000 proteins. Herein, an integrated proteogenomic analysis for inherited bone marrow failure syndrome (IBMFS) was performed to reveal their biological features and to develop a proteomic-based diagnostic assay in the discovery cohort; dyskeratosis congenita (n = 12), Fanconi anemia (n = 11), Diamond-Blackfan anemia (DBA, n = 9), Shwachman-Diamond syndrome (SDS, n = 6), ADH5/ALDH2 deficiency (n = 4), and other IBMFS (n = 18). Unsupervised proteomic clustering identified eight independent clusters (C1-C8), with the ribosomal pathway specifically downregulated in C1 and C2, enriched for DBA and SDS, respectively. Six patients with SDS had significantly decreased SBDS protein expression, with two of these not diagnosed by DNA sequencing alone. Four patients with ADH5/ALDH2 deficiency showed significantly reduced ADH5 protein expression. To perform a large-scale rapid IBMFS screening, targeted proteomic analysis was performed on 417 samples from patients with IBMFS-related hematological disorders (n = 390) and healthy controls (n = 27). SBDS and ADH5 protein expressions were significantly reduced in SDS and ADH5/ALDH2 deficiency, respectively. The clinical application of this first integrated proteogenomic analysis would be useful for the diagnosis and screening of IBMFS, where appropriate clinical screening tests are lacking.

A naturally occurring canine model of syndromic congenital microphthalmia.

In humans, the prevalence of congenital microphthalmia is estimated to be 0.2-3.0 for every 10,000 individuals, with nonocular involvement reported in ∼80% of cases. Inherited eye diseases have been widely and descriptively characterized in dogs, and canine models of ocular diseases have played an essential role in unraveling the pathophysiology and development of new therapies. A naturally occurring canine model of a syndromic disorder characterized by microphthalmia was discovered in the Portuguese water dog. As nonocular findings included tooth enamel malformations, stunted growth, anemia, and thrombocytopenia, we hence termed this disorder Canine Congenital Microphthalmos with Hematopoietic Defects. Genome-wide association study and homozygosity mapping detected a 2 Mb candidate region on canine chromosome 4. Whole-genome sequencing and mapping against the Canfam4 reference revealed a Short interspersed element insertion in exon 2 of the DNAJC1 gene (g.74,274,883ins[T70]TGCTGCTTGGATT). Subsequent real-time PCR-based mass genotyping of a larger Portuguese water dog population found that the homozygous mutant genotype was perfectly associated with the Canine Congenital Microphthalmos with Hematopoietic Defects phenotype. Biallelic variants in DNAJC21 are mostly found to be associated with bone marrow failure syndrome type 3, with a phenotype that has a certain degree of overlap with Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, Diamond-Blackfan anemia, and reports of individuals showing thrombocytopenia, microdontia, and microphthalmia. We, therefore, propose Canine Congenital Microphthalmos with Hematopoietic Defects as a naturally occurring model for DNAJC21-associated syndromes.

ПРИМЕНЕНИЕ ЛЕЙЦИНА У ПАЦИЕНТА С СИНДРОМОМ ШВАХМАНА-ДАЙМОНДА: КЛИНИЧЕСКОЕ НАБЛЮДЕНИЕ

Schwachman-Diamond syndrome (SDS) is a rare autosomal recessive disease from the group of ribosomopathies characterized by exocrine pancreatic insufficiency, bone marrow dysfunction, malnutrition, protein-energy malnutrition, growth retardation, skeletal abnormalities and a predisposition to the development of myelodysplastic syndrome and acute myeloid leukemia. Severe hematological disorders, a high risk of developing MDS/AML, with a high percentage of unfavorable outcomes, prompted the consideration of alternative routes for the therapy in these circumstances. The possibility for the use of L-leucine, an essential amino acid, as a pathogenetic therapy in patients with severe dyshematopoiesis in SDS by analogy with its use in another ribosomopathy disease, Diamond-Blackfan anemia (DBA), is discussed in the Article.

Genetic backgrounds and clinical characteristics of congenital neutropenias in Israel.

Congenital neutropenias are characterized by severe infections and a high risk of myeloid transformation; the causative genes vary across ethnicities. The Israeli population is characterized by an ethnically diverse population with a high rate of consanguinity. To evaluate the clinical and genetic spectrum of congenital neutropenias in Israel. We included individuals with congenital neutropenias listed in the Israeli Inherited Bone Marrow Failure Registry. Sanger sequencing was performed for ELANE or G6PC3, and patients with wild-type ELANE/G6PC3 were referred for next-generation sequencing. Sixty-five patients with neutropenia were included. Of 51 patients with severe congenital neutropenia, 34 were genetically diagnosed, most commonly with variants in ELANE (15 patients). Nine patients had biallelic variants in G6PC3, all of consanguineous Muslim Arab origin. Other genes involved were SRP54, JAGN1, TAZ, and SLC37A4. Seven patients had cyclic neutropenia, all with pathogenic variants in ELANE, and seven had Shwachman-Diamond syndrome caused by biallelic SBDS variants. Eight patients (12%) developed myeloid transformation, including six patients with an unknown underlying genetic cause. Nineteen (29%) patients underwent hematopoietic stem cell transplantation, mostly due to insufficient response to treatment with granulocyte-colony stimulating factor or due to myeloid transformation. The genetic spectrum of congenital neutropenias in Israel is characterized by a high prevalence of G6PC3 variants and an absence of HAX1 mutations. Similar to other registries, for 26% of the patients, a molecular diagnosis was not achieved. However, myeloid transformation was common in this group, emphasizing the need for close follow-up.

Clinical and genetic characteristics of Chinese patients with Shwachman Diamond syndrome: a literature review of Chinese publication.

Shwachman Diamond syndrome (SDS) is a rare autosomal recessive genetic disorder and due to its complex and varied clinical manifestations, diagnosis is often delayed. The purpose of this study was to investigate the clinical manifestations and genetic characteristics of SDS in Chinese patients, in order to increase pediatricians' awareness of SDS and to allow early diagnosis. We conducted a search to identify patients presenting SBDS gene pathogenic variant in two Chinese academic databases. We analyzed and summarized the epidemiology, clinical features, gene pathogenic variants, and key points in the diagnosis and treatment of SDS. We reviewed the clinical data of 39 children with SDS from previously published articles. The interval from the onset of the first symptoms to diagnosis was very long for most of our patients. The age of presentation ranged from 1day to 10years (median: 3months). However, the age of diagnosis was significantly delayed, ranging from 1month to 14years (median: 14months). Hematological abnormalities were the most common presentation, 89.7% (35/39) at the beginning and 94.9% (37/39) at diagnosis of SDS. Diarrhea was the second most common clinical abnormality at the time of diagnosis. 59% (23/39) of patients had a typical history of persistent chronic diarrhea. Furthermore, hepatic enlargement or elevation of transaminase occurred in 15 cases (38.5%). 56.4% patients (22/39) had a short stature, and 17.9% (7/39) patients showed developmental delay. Additionally, twenty patients had compound heterozygous pathogenic variants of c.258 + 2T > C and c.183_ 184TA > CT. Children with SDS in China had high incidence rates of chronic diarrhea, cytopenia, short stature, and liver damage. Furthermore, SBDS c.258 + 2T > C and c.183_ 184TA > CT were the most common pathogenic variants in patients with SDS. The diagnosis of SDS can be delayed if the clinical phenotype is not recognized by the health care provider.

Growth Charts for Shwachman-Diamond Syndrome at Ages 0 to 18 Years.

Shwachman-Diamond syndrome (SDS) is one of the most common inherited bone marrow failure syndromes. SDS is characterized by hypocellular bone marrow, with a severe impairment of the myeloid lineage, resulting in neutropenia, thrombocytopenia, and, more rarely, anemia. Almost 15% of patients with SDS develop myelodysplastic syndrome or acute myeloid leukemia as early as childhood or young adulthood. Exocrine pancreatic insufficiency is another common feature of SDS. Almost all patients with SDS show failure to thrive, which is associated with skeletal abnormalities due to defective ossification. Considering these observations, it remains unfeasible to use the common growth charts already available for the general population. To address this issue, we report how we drew up growth charts of patients with SDS aged 0 to 18 years. We analyzed height, weight, and body max index (BMI) in 121 Italian patients with SDS. Results indicated that the 50th and 3rd percentiles of weight and height of the pediatric general population correspond to the 97th and 50th percentiles of patients with SDS aged 0-18 years, respectively. In addition, the percentage increment in weight of subjects aged 14-18 years was higher in patients with SDS than in the general population. SDS-specific growth charts, such as those described here, afford a new tool, which is potentially useful for both clinical and research purposes in SDS.

Abstract 7078: Targeting eIF6 to modulate ribosomal subunit association dynamics in cancers

Abstract Deregulation of ribosomal subunit levels and accessibility are hallmarks of cancer. Eukaryotic translation initiation factor 6 (eIF6) is a key regulator of ribosomal subunit association that is over expressed in many cancers including lung, colon, ovarian and breast cancers, and deregulation of eIF6 is correlated with a poor cancer prognosis. Association of eIF6 with 60S is critical for 60S assembly. However, eIF6 must be released from 60S prior to translation to permit inter subunit interactions between 60S and 40S and to facilitate the formation of translationally proficient 80S monosome. Release of eIF6 is deregulated in the ribosomopathy- Shwachman Diamond Syndrome that is predisposed to leukemias. Also, loss of eIF6 markedly delays tumorigenesis without affecting normal growth, which presents eIF6 as a viable therapeutic target. A potential therapeutic strategy is to target the eIF6 and 60S ribosomal interaction interface. Through biophysical analyses we had identified residues that are critical for the interaction between eIF6 and 60S ribosomal subunit. We show that targeting these key residues in the eIF6-60S interaction interface markedly delays colonic cancer growth and inhibits protein synthesis. Furthermore, we show that the levels of other eIFs and the release factors: SBDS, and EFL1-GTPase are unaltered in the mutant cells suggesting that the translational inhibition is primarily attributed to the deregulation of eIF6. Interestingly, targeting eIF6 leads to an upregulation of p53 independent of the DNA damage response, suggesting that ribosomal stress contributes to the stabilization of p53. Previously, it was shown that translation of Cdc42 was upregulated by eIF6 to promote invasiveness. However, Cdc42 levels were unaltered in the mutant cells. Future studies will determine the mRNA substrates that are translationally deregulated in the mutants. We will also determine the effect of disrupting eIF6 function in inhibiting tumor growth and progression in vivo. Category: MCB, Subcategory: MCB07-Gene regulation sub classification: Translational Control Citation Format: Kavya Meena Harish, Poonam Roshan, Aparna Biswas, Stella Anagnos, Riley Luebbers, Sofia Origanti. Targeting eIF6 to modulate ribosomal subunit association dynamics in cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7078.

Синдром Швахмана–Даймонда. Не редкие симптомы у редкого пациента

The article presents modern information about the congenital disease of the pancreas - Shwachman-Diamond syndrome. Own observation and results of the examination of the child with the specified syndrome are given.