Incidence of Shwachman-Diamond syndrome

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 1 day to 10 years (median: 3 months). However, the age of diagnosis was significantly delayed, ranging from 1 month to 14 years (median: 14 months). 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.

A Rare Inherited Bone Marrow Failure Syndrome Disclosed by Reanalysis of the Exome Data of a Patient Evaluated for Cytopenia and Dysmorphic Features

BACKGROUND

Multisystemic findings of inherited bone marrow failure syndromes may cause difficulty in diagnosis. Exome sequencing (ES) helps to define the etiology of rare diseases and reanalysis offers a valuable new diagnostic approach. Herein, we present the clinical and molecular characteristics of a girl who was referred for cytopenia and frequent infections.

CASE REPORT

A 5-year-old girl with cytopenia, dysmorphism, short stature, developmental delay, and myopia was referred for genetic counseling. Reanalysis of the ES data revealed a homozygous splice-site variant in the DNAJC21 (NM_001012339.3:c.983+1G>A), causing Shwachman-Diamond Syndrome (SDS). It was shown by the RNA sequencing that exon 7 was skipped, causing an 88-nucleotide deletion.

CONCLUSIONS

Precise genetic diagnosis enables genetic counseling and improves patient management by avoiding inappropriate treatment and unnecessary testing. This report would contribute to the clinical and molecular understanding of this rare type of SDS caused by DNAJC21 variants and expand the phenotypic features of this condition.

Shwachman-Diamond syndromes: clinical, genetic, and biochemical insights from the rare variants

Shwachman-Diamond syndrome is a rare inherited bone marrow failure syndrome characterized by neutropenia, exocrine pancreatic insufficiency, and skeletal abnormalities. In 10-30% of cases, transformation to a myeloid neoplasm occurs. Approximately 90% of patients have biallelic pathogenic variants in the SBDS gene located on human chromosome 7q11. Over the past several years, pathogenic variants in three other genes have been identified to cause similar phenotypes; these are DNAJC21, EFL1, and SRP54. Clinical manifestations involve multiple organ systems and those classically associated with the Shwachman-Diamond syndrome (bone, blood, and pancreas). Neurocognitive, dermatologic, and retinal changes may also be found. There are specific gene-phenotype differences. To date, SBDS, DNAJC21, and SRP54 variants have been associated with myeloid neoplasia. Common to SBDS, EFL1, DNAJC21, and SRP54 is their involvement in ribosome biogenesis or early protein synthesis. These four genes constitute a common biochemical pathway conserved from yeast to humans that involve early stages of protein synthesis and demonstrate the importance of this synthetic pathway in myelopoiesis.

The Molecular and Genetic Mechanisms of Inherited Bone Marrow Failure Syndromes: The Role of Inflammatory Cytokines in Their Pathogenesis

Inherited bone marrow failure syndromes (IBMFSs) include Fanconi anemia, Diamond-Blackfan anemia, Shwachman-Diamond syndrome, dyskeratosis congenita, severe congenital neutropenia, and other rare entities such as GATA2 deficiency and SAMD9/9L mutations. The IBMFS monogenic disorders were first recognized by their phenotype. Exome sequencing has validated their classification, with clusters of gene mutations affecting DNA damage response (Fanconi anemia), ribosome structure (Diamond-Blackfan anemia), ribosome assembly (Shwachman-Diamond syndrome), or telomere maintenance/stability (dyskeratosis congenita). The pathogenetic mechanisms of IBMFSs remain to be characterized fully, but an overarching hypothesis states that different stresses elicit TP53-dependent growth arrest and apoptosis of hematopoietic stem, progenitor, and precursor cells. Here, we review the IBMFSs and propose a role for pro-inflammatory cytokines, such as TGF-β, IL-1β, and IFN-α, in mediating the cytopenias. We suggest a pathogenic role for cytokines in the transformation to myeloid neoplasia and hypothesize a role for anti-inflammatory therapies.

Improved detection of SBDS gene mutation by a new method of next-generation sequencing analysis based on the Chinese mutation spectrum

Next-generation sequencing (NGS) is a useful molecular diagnostic tool for genetic diseases. However, due to the presence of highly homologous pseudogenes, it is challenging to use short-read NGS for analyzing mutations of the Shwachman-Bodian-Diamond syndrome (SBDS) gene. The SBDS mutation spectrum was analyzed in the Chinese population, which revealed that SBDS variants were primarily from sequence exchange between SBDS and its pseudogene at the base-pair level, predominantly in the coding region and splice junction of exon two. The c.258+2T>C and c.185_184TA>GT variants were the two most common pathogenic SBDS variants in the Chinese population, resulting in a total carrier frequency of 1.19%. When analyzing pathogenic variants in the SBDS gene from the NGS data, the misalignment was identified as a common issue, and there were different probabilities of misalignment for different pathogenic variants. Here, we present a novel mathematical method for identifying pathogenic variants in the SBDS gene from the NGS data, which utilizes read-depth of the paralogous sequence variant (PSV) loci of SBDS and its pseudogene. Combined with PCR and STR orthogonal experiments, SBDS gene mutation analysis results were improved in 40% of clinical samples, and various types of mutations such as homozygous, compound heterozygous, and uniparental diploid were explored. The findings effectively reduce the impact of misalignment in NGS-based SBDS mutation analysis and are helpful for the clinical diagnosis of SBDS-related diseases, the research into population variation, and the carrier screening.

Shwachman-Diamond Syndrome in a Child Presenting With Chronic Diarrhea: A Rare Case in Family Medicine Practice

Diarrhea remains an important cause of morbidity and mortality worldwide. Chronic diarrhea often represents a diagnostic challenge for family medicine and pediatric physicians because of its broad spectrum of possible etiologies. The differential diagnoses can be narrowed by taking a detailed history and performing an appropriate physical examination. In general, chronic diarrhea can be due to osmotic, secretory, inflammatory, or dysmotility-related pathologies. We present the case of a 30-month-old male who was brought to the family medicine clinic with a complaint of abdominal bloating and persistent diarrhea after every feeding for four months. His stools were foul-smelling and occurred more than four times a day. The patient was below the second standard deviations for weight and height. He appeared pale, and there was no scleral icterus. The patient underwent upper endoscopy, which showed no abnormal gross findings. A dedicated abdominal computed tomography scan was performed to evaluate the pancreas for any structural abnormalities. The scan demonstrated complete replacement of the pancreatic parenchyma by fatty tissue. The diagnosis of Shwachman-Diamond syndrome was established as the analysis revealed a mutation in the SBDS gene. The patient was treated with pancreatic enzyme replacement therapy. After two months of follow-up, the parents reported that the patient had significant improvement in diarrhea. Shwachman-Diamond syndrome is a very rare inherited disorder characterized by bone marrow failure, exocrine pancreatic dysfunction, and skeletal abnormalities. Despite its rarity, clinicians should keep a high index for this condition when they encounter a child with unexplained chronic diarrhea.

Shwachman-diamond syndrome: A case report

RATIONALE

The aim of this study was to analyze the genetic abnormalities and clinical manifestations of Shwachman-Diamond syndrome (SDS).

PATIENT CONCERNS

A Chinese infant with elevated transaminase and a novel mutation at of sbdsc.258 +2T>C and c.184a>Tc.292G>A.

DIAGNOSES

The female patient was 5 months' old at onset, with elevated transaminase as the first manifestation accompanied by restricted growth and development and oily stool. After sequencing the blood samples from patients and their parents, the heterozygous mutations of sbdsc.258 +2T>C and c.184a>T were detected.

INTERVENTIONS

After admission, the patient was provided compound glycyrrhizin, Newtide formula milk supplemented with probiotics, fat-soluble vitamins, oral medication to adjust the spleen and stomach, and other symptomatic treatments.

OUTCOMES

The stool traits improved, and the levels of liver function transaminases decreased compared with before.

LESSONS

SDS is a rare disease with a variety of clinical manifestations. Pancreatic exocrine dysfunction, blood system manifestations, and bone abnormalities are common clinical manifestations, and genetic testing is helpful for diagnosis.

Somatic development in children with Shwachman-Diamond syndrome

BACKGROUND

Shwachman-Diamond syndrome (SDS) is a rare genetic, multi-systemic disease characterized by exocrine pancreatic insufficiency, immune deficiency, bone marrow failure and skeletal abnormalities. Most patients present with failure in somatic development and short stature, but systematic data concerning those features are limited. The aim of the study was to assess the prevalence of failure in somatic development in the children with SDS.

METHODS

An analysis of anthropometric measurements of 21 patients (14 girls and 7 boys),aged 2 to 17 years (mean age 6.3 years) with SDS diagnosed in The Children's Memorial Health Institute in Warsaw, Poland was performed. The patients were measured using a Holtain Limited stadiometer, an electronic scale, a Harpenden anthropometer, a metric tape and a spreading caliper. The assessed anthropometric parameters were expressed as standard deviation scores in relation to the reference values in Poland, suitable for sex as well as calendar and growth age.

RESULTS

A total of 66 measurements was collected and analyzed with a median number of 3 observations per patient. The group of boys presented with a significantly lower height (- 3.0 SD, p < 0.0001) and BMI (- 1.4 SD, p < 0.00001), and in the relation to the growth age a lower weight (- 1.0 SD, p < 0.001) as well as a smaller chest width (- 0.9 SD, p < 0.05), hip width (- 0,5 SD, p < 0,05) and lower limb length (- 0,5 SD, p < 0,05). The group of girls also showed significantly lower height (- 2.6 SD, p < 0.00001) and BMI (- 0.8 SD, p < 0.00001), and in relation to the growth age, lower weight (- 0.5 SD, p < 0.001) as well as decreased width of the chest (- 1.7 SD, p < 0.0001) and shoulder (- 1.0 SD, p < 0.001) were observed. Boys and girls were also characterized by significantly decreased circumference and width of head, additionally, girls had also smaller head length.

CONCLUSIONS

Patients with SDS have abnormal somatic development. Both boys and girls are characterized by short stature, decreased weight, BMI, leg length, chest width as well as circumference and width of head. Anthropometric measurements provide important data on the process of growth and body proportions in children with SDS.

A Prospective Study of Hematologic Complications and Long-Term Survival of Italian Patients Affected by Shwachman-Diamond Syndrome

OBJECTIVE

To describe the hematologic outcome and long-term survival of patients enrolled in the Shwachman-Diamond syndrome Italian Registry.

STUDY DESIGN

A retrospective and prospective study of patients recorded in the Shwachman-Diamond syndrome Italian Registry.

RESULTS

The study population included 121 patients, 69 males and 52 females, diagnosed between 1999 and 2018. All patients had the clinical diagnosis confirmed by mutational analysis on the SBDS gene. During the study period, the incidence of SDS was 1 in 153 000 births. The median age of patients with SDS at diagnosis was 1.3 years (range, 0-35.6 years). At the first hematologic assessment, severe neutropenia was present in 25.8%, thrombocytopenia in 25.5%, and anemia in 4.6% of patients. A normal karyotype was found in 40 of 79 patients, assessed whereas the most frequent cytogenetic abnormalities were isochromosome 7 and interstitial deletion of the long arm of chromosome 20. The cumulative incidence of severe neutropenia, thrombocytopenia, and anemia at 30 years of age were 59.9%, 66.8%, and 20.2%, respectively. The 20-year cumulative incidence of myelodysplastic syndrome/leukemia and of bone marrow failure/severe cytopenia was 9.8% and 9.9%, respectively. Fifteen of 121 patients (12.4%) underwent allogeneic stem cell transplantation. Fifteen patients (12.4%) died; the probability of overall survival at 10 and 20 years was 95.7% and 87.4%, respectively.

CONCLUSIONS

Despite an improvement in survival, hematologic complications still cause death in patients with SDS. Further studies are needed to optimize type and modality of hematopoietic stem cell transplantation and to assess the long-term outcome in nontransplanted patients.

Pancreatic Malnutrition in Children

Exocrine pancreatic insufficiency in children can lead to lifelong complications related to malnutrition and poor growth. The clinical presentation can be subtle in the early stages of insufficiency as the large functional capacity of the pancreas is gradually lost. The pediatrician plays a crucial role in the early identification of these children to ensure a timely referral so that a diagnosis can be made and therapy initiated. Early nutritional therapy allows for prevention and correction of deficiencies, which leads to improved outcomes and survival. When insufficiency is suspected, the workup should start with an indirect test of exocrine pancreatic function, such as fecal elastase, to establish the diagnosis. Once a diagnosis is established, further testing to delineate the etiology should be pursued, with cystic fibrosis being high on the differential list and assessed for with a sweat test. Assessment of anthropometry at every visit is key, as is monitoring of laboratory parameters and physical examination findings that are suggestive of malabsorption and malnutrition. The mainstay of management is administration of exogenous pancreatic enzymes to facilitate digestion and absorption. [Pediatr Ann. 2019;48(11):e441-e447.].

Peripheral blood immunophenotyping in a large cohort of patients with Shwachman-Diamond syndrome

Shwachman-Diamond syndrome (SDS) is one of the more common inherited bone marrow failure syndromes, characterized by neutropenia, occasional thrombocytopenia, and anemia. Bone marrow evaluation reveals an increased number of monocytes and mature B cells along with decreased granulocytes. However, little is known about the subpopulations of peripheral blood cells, and few previous publications have been based on a small number of patients. Here, we report a comprehensive immunophenotypic analysis from a cohort of 37 SDS patients who display impairment mostly in the myeloid compartment with a deficiency also in the number of B cells and CD4/CD8 double-negative T cells.

Clinical Characteristics and Genetic Causes of Infantile Exocrine Pancreatic Insufficiency in Chinese Patients: Study From a Tertiary Care Center

OBJECTIVE

Infantile exocrine pancreatic insufficiency is a rare disease. We examined phenotypes and performed genetic sequencing in children with this disorder.

METHODS

We enrolled 4 infants with exocrine pancreatic insufficiency. Patients were characterized by phenotypes and radiologic findings. Genetic sequencing was performed.

RESULTS

Average age of disease onset was 2 months. Average (standard deviation [SD]) age at diagnosis was 11.9 (7.0) months. Patients presented with chronic steatorrhea and failure to thrive. Two had mild zinc deficiency. Imaging showed pancreatic lipomatosis and metaphyseal dysplasia among all patients. For these patients with similar phenotypes, genetic sequencing revealed that 2 patients had novel UBR1 mutations (c.[3043_3046delAAAG; c.3848 + 6T > C] and c.[1850-2A > T;c.4290T > G], reference sequence NM_174916), and another 2 patients had homozygous SBDS c.258 + 2T > C mutation and SBDS c.[258 + 2T > C;c.428C > T] mutations (reference sequence NM_016038.2). All patients received pancreatic enzyme replacement therapy.

CONCLUSIONS

Here we described 4 patients with infantile exocrine pancreatic insufficiency confirmed by laboratory tests and imaging. Whole-exome sequencing and Sanger sequencing showed that 2 patients had Johanson-Blizzard syndrome and 2 patients had Shwachman-Diamond syndrome. Genetic sequencing should be applied for definite diagnosis among these patients.

Ataluren-driven restoration of Shwachman-Bodian-Diamond syndrome protein function in Shwachman-Diamond syndrome bone marrow cells

Shwachman-Diamond syndrome (SDS) is a rare inherited recessive disease mainly caused by mutations in the Shwachman-Bodian-Diamond syndrome (SBDS) gene, which encodes for the homonymous protein SBDS, whose function still remains to be fully established. SDS affects several organs causing bone marrow failure, exocrine pancreatic insufficiency, skeletal malformations, and cognitive disorders. About 15% of SDS patients develop myelodysplastic syndrome (MDS) and are at higher risk of developing acute myeloid leukemia (AML). Deficiency in SBDS expression has been associated with increased apoptosis and lack of myeloid differentiation in bone marrow hematopoietic progenitors. Importantly, most SDS patients carry nonsense mutations in SBDS. Since ataluren is a well-characterized small molecule inhibitor that can suppress nonsense mutations, here, we have assessed the efficacy of this drug in restoring SBDS expression in hematopoietic cells obtained from a cohort of SDS patients. Remarkably, we show that ataluren treatment readily restores SBDS protein expression in different cell types, particularly bone marrow stem cells. Furthermore, ataluren promotes myeloid differentiation in hematopoietic progenitors, reduces apoptotic rate in primary PBMCs, and brings mammalian target of rapamycin phosphorylation levels back to normal in both lymphoblasts and bone marrow mesenchymal stromal cells (BM-MSCs). Since a specific therapy against SDS is currently lacking, these results provide the rationale for ataluren repurposing clinical trials.

The Greek Registry of Shwachman Diamond-Syndrome: Molecular and clinical data

This study presents the clinical phenotype and molecular analysis findings from 11 patients recorded in the Greek Shwachman-Diamond syndrome (SDS) Registry. The most severely affected patient in our registry was diagnosed at birth and is the first patient reported to require bone marrow transplantation so early in life. Severe psoriasis, a feature not previously reported in SDS, was observed in one patient. Mutations in the Shwachman-Bodian-Diamond syndrome gene (SBDS) were found in all patients. Cytogenetic analyses revealed clonal abnormalities, one novel, in two patients.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

New insights into the Shwachman-Diamond Syndrome-related haematological disorder: hyper-activation of mTOR and STAT3 in leukocytes

Shwachman-Diamond syndrome (SDS) is an inherited disease caused by mutations of a gene encoding for SBDS protein. So far little is known about SBDS exact function. SDS patients present several hematological disorders, including neutropenia and myelodysplastic syndrome (MDS), with increased risk of leukemic evolution. So far, the molecular mechanisms that underlie neutropenia, MDS and AML in SDS patients have been poorly investigated. STAT3 is a key regulator of several cellular processes including survival, differentiation and malignant transformation. Moreover, STAT3 has been reported to regulate neutrophil granulogenesis and to induce several kinds of leukemia and lymphoma. STAT3 activation is known to be regulated by mTOR, which in turn plays an important role in cellular growth and tumorigenesis. Here we show for the first time, to the best of our knowledge, that both EBV-immortalized B cells and primary leukocytes obtained from SDS patients present a constitutive hyper-activation of mTOR and STAT3 pathways. Interestingly, loss of SBDS expression is associated with this process. Importantly, rapamycin, a well-known mTOR inhibitor, is able to reduce STAT3 phosphorylation to basal levels in our experimental model. A novel therapeutic hypothesis targeting mTOR/STAT3 should represent a significant step forward into the SDS clinical practice.

Can continuous subcutaneous insulin infusion improve health-related quality of life in patients with Shwachman-Bodian-Diamond syndrome and diabetes?

We report the first case of the use of continuous subcutaneous insulin infusion (CSII) in a patient with Shwachman-Bodian-Diamond syndrome (SBDS) and diabetes. An Italian boy received diagnosis of SBDS at the age of 7 months (SBDS gene mutation: c.183-184TA → CT and c.258 + 2 T → C in compound heterozygous). The patient presented an impaired psychosocial functioning with difficulties in mental health, body pain experiences, attention deficit disorder, somatic complaints, behavioral and social problems. Total Intelligence Quotient (T-IQ) was within the normal range for age (T-IQ = 109). The patient developed clinical diabetes at the age of 13 years (glycemia 282 mg/dL at 120 min of oral glucose tolerance test, glycosylated hemoglobin level of 7.5%, anti-β-cell antibodies negative; glucagon test yielding a C peptide level at zero-time of 1.5 ng/mL and at 6 min of 2.0 ng/mL). Multiple daily injection therapy with insulin was started. Nevertheless, because of a relevant needle phobia and the recurrent hypoglycemia due to poor nutrition secondary to depression, after 3 years the patient started CSII. After 12 months a new evaluation showed (1) better social adaptation, (2) meliorated self-esteem and self-efficacy, (3) reduced psychosocial suffering, and (4) improved health-related quality of life, assessed by the Pediatric Quality of Life Inventory version 3.0 Diabetes Module. Thus CSII seems to be crucial to improve health-related quality of life in patients affected by diabetes and genetic disorders.