Burkitt lymphoma and Williams syndrome: a model for children with a multisystem disorder and malignancy

Williams-Beuren syndrome in pediatric T-cell acute lymphoblastic leukemia: A rare case report and review of literature

BACKGROUND

Williams-Beuren syndrome (WBS) is a rare genetic disorder caused by hemizygous microdeletion of contiguous genes on chromosome 7q11.23. Although the phenotype features extensive heterogeneity in severity and performance, WBS is not considered to be a predisposing factor for cancer development. Currently, hematologic cancers, mainly Burkitt lymphoma, are rarely reported in patients with WBS. Here in, we report a unique case of T-cell acute lymphoblastic leukemia in a male child with WBS.

METHODS

This retrospective study analyzed the clinical data of this case receiving chemotherapy were analyzed. This is a retrospective study.

RESULTS

The patient, who exhibited a typical WBS phenotype and presented with hemorrhagic spots. Chromosomal genome-wide chip analysis (CMA) revealed abnormalities on chromosomes 7 and 9. The fusion gene STIL-TAL1 and mutations in BCL11B, NOTCH1, and USP7 have also been found and all been associated with the occurrence of T-cell leukemia. The patient responded well to the chemotherapy.

CONCLUSION

To the best of our knowledge, this is the first reported case of WBS in T-cell acute lymphoblastic leukemia. We want to emphasize that the occurrence of leukemia in this patient might be related to the loss of 7q11.23 and microdeletion of 9p21.3 (including 3 TSGs), but the relationship between WBS and malignancy remains unclear. Further studies are required to clarify the relationship between WBS and malignancy.

Williams-Beuren Syndrome as a Potential Risk Factor for Burkitt Lymphoma

Williams–Beuren syndrome (WBS) is a multisystemic neurodevelopmental disorder caused by a hemizygous deletion on chromosome 7q11.23. Though at present there is a limited number of reports on WBS patients with tumors, most cases are related to blood cancer in children with WBS. We describe a case of Burkitt lymphoma in a 21-year-old man with WBS. In addition to providing a summary of published reports describing tumors observed in patients with WBS, we present a hypothesis about a possible mechanism of oncogenesis. In particular, we identified some significantly dysregulated cancer-related genes using blood samples from this patient at the age of 19 years (who have not yet developed Burkitt lymphoma). Our findings may provide a new perspective on the relation between WBS and Burkitt lymphoma.

The Tumor Suppressor BCL7B Functions in the Wnt Signaling Pathway

Human BCL7 gene family consists of BCL7A, BCL7B, and BCL7C. A number of clinical studies have reported that BCL7 family is involved in cancer incidence, progression, and development. Among them, BCL7B, located on chromosome 7q11.23, is one of the deleted genes in patients with Williams-Beuren syndrome. Although several studies have suggested that malignant diseases occurring in patients with Williams-Beuren syndrome are associated with aberrations in BCL7B, little is known regarding the function of this gene at the cellular level. In this study, we focused on bcl-7, which is the only homolog of BCL7 gene family in Caenorhabditis elegans, and analyzed bcl-7 deletion mutants. As a result, we found that bcl-7 is required for the asymmetric differentiation of epithelial seam cells, which have self-renewal properties as stem cells and divide asymmetrically through the WNT pathway. Distal tip cell development, which is regulated by the WNT pathway in Caenorhabditis elegans, was also affected in bcl-7-knockout mutants. Interestingly, bcl-7 mutants exhibited nuclear enlargement, reminiscent of the anaplastic features of malignant cells. Furthermore, in KATOIII human gastric cancer cells, BCL7B knockdown induced nuclear enlargement, promoted the multinuclei phenotype and suppressed cell death. In addition, this study showed that BCL7B negatively regulates the Wnt-signaling pathway and positively regulates the apoptotic pathway. Taken together, our data indicate that BCL7B/BCL-7 has some roles in maintaining the structure of nuclei and is involved in the modulation of multiple pathways, including Wnt and apoptosis. This study may implicate a risk of malignancies with BCL7B-deficiency, such as Williams-Beuren syndrome.

BCL7B, a member of the human BCL7 gene family, is deleted in patients with Williams-Beuren syndrome. Although several clinical studies have suggested that malignant diseases occurring in patients with Williams-Beuren syndrome are associated with aberrations in BCL7B, little is known regarding the physiological function of this gene. Here, we show that bcl-7, the only homolog of BCL7 gene family in Caenorhabditis elegans, regulates asymmetric cell differentiation in somatic “stem-like” seam cells through at least the Wnt pathway and promotes the apoptotic pathway. In addition, bcl-7 deletion mutants show enlarged nuclei in epidermis and germ cells. Furthermore, in KATOIII human gastric cancer cells, BCL7B knockdown induces nuclear enlargement, as observed in Caenorhabditis elegans, and promotes the multinucleated phenotype, both of which are reminiscent of malignant diseases. BCL7B also negatively regulates the Wnt-signaling pathway and positively regulates the apoptotic pathway, similar to Caenorhabditis elegans. Altogether, this study may open the door for understanding the function of BCL7 family in cell differentiation and malignancies.

Constitutional and somatic deletions of the Williams-Beuren syndrome critical region in non-Hodgkin lymphoma

Here, we report and investigate the genomic alterations of two novel cases of Non-Hodgkin Lymphoma (NHL) in children with Williams-Beuren syndrome (WBS), a multisystem disorder caused by 7q11.23 hemizygous deletion. Additionally, we report the case of a child with NHL and a somatic 7q11.23 deletion. Although the WBS critical region has not yet been identified as a susceptibility locus in NHL, it harbors a number of genes involved in DNA repair. The high proportion of pediatric NHL reported in WBS is intriguing. Therefore, the role of haploinsufficiency of genes located at 7q11.23 in lymphomagenesis deserves to be investigated.

Burkitt lymphoma and Ewing sarcoma in a child with Williams syndrome

Williams syndrome (WS) is a relatively rare multisystem neurodevelopmental disorder caused by a hemizygous deletion of contiguous genes on chromosome 7q11.23. Although WS does not predispose carriers to cancers, alterations of chromosome 7 are common in several human neoplasms. We report here a patient with WS and two different cancers, Burkitt lymphoma and Ewing sarcoma. Array-CGH analysis of the patient blood revealed a constitutive 1.4 million base pair deletion at 7q11.23, compatible with WS diagnosis.

Pilomyxoid astrocytoma of the cerebellum with Williams syndrome: a case report

CASE REPORT

A 3-year-old boy with Williams syndrome associated with supravalvular aortic stenosis was admitted to our hospital with disturbance of consciousness and a 2-month history of truncal ataxia. T1-weighted magnetic resonance imaging with contrast medium showed a heterogeneously enhanced tumor in the right cerebellum with severe hydrocephalus. The patient underwent tumor resection via suboccipital craniotomy. At the end of resection of the tumor, sudden cardiac arrest occurred after ST segment elevation. Despite immediate cardiopulmonary resuscitation, the patient died. Histological examination of the cerebellar tumor revealed that the tumor consisted of monomorphous bipolar spindle cells on a background of myxoid matrix, and angiocentric arrangement without Rosenthal fibers or eosinophilic granular body. The final diagnosis was pilomyxoid astrocytoma.

CONCLUSION

This case of Williams syndrome with cerebellar pilomyxoid astrocytoma suggests the importance of investigation of the development of brain tumors and occurrence of intraoperative cardiac arrest associated with Williams syndrome.

Williams-Beuren Syndrome and Burkitt Leukemia

Williams-Beuren Syndrome (WBS) is associated with constitutional deletion of 7q11.23, which includes the elastin gene. Cytogenetic abnormalities of chromosome 7 are frequently described in several human malignancies. Here, we report Burkitt Leukemia in an 8-year-old boy with WBS. In this patient, constitutional deletion of chromosome 7q11.23 including BCL7B was confirmed. WBS may predispose patients to Burkitt Leukemia.

Haploinsufficiency of DNA Damage Response Genes and their Potential Influence in Human Genomic Disorders

Genomic disorders are a clinically diverse group of conditions caused by gain, loss or re-orientation of a genomic region containing dosage-sensitive genes. One class of genomic disorder is caused by hemizygous deletions resulting in haploinsufficiency of a single or, more usually, several genes. For example, the heterozygous contiguous gene deletion on chromosome 22q11.2 causing DiGeorge syndrome involves at least 20-30 genes. Determining how the copy number variation (CNV) affects human variation and contributes to the aetiology and progression of various genomic disorders represents important questions for the future. Here, I will discuss the functional significance of one form of CNV, haploinsufficiency (i.e. loss of a gene copy), of DNA damage response components and its association with certain genomic disorders. There is increasing evidence that haploinsufficiency for certain genes encoding key players in the cells response to DNA damage, particularly those of the Ataxia Telangiectasia and Rad3-related (ATR)-pathway, has a functional impact. I will review this evidence and present examples of some well known clinically similar genomic disorders that have recently been shown to be defective in the ATR-dependent DNA damage response. Finally, I will discuss the potential implications of a haploinsufficiency-induced defective DNA damage response for the clinical management of certain human genomic disorders.

Bilateral burkitt lymphoma of the ovaries: a report of a case in a child with williams syndrome

A 10-year-old female with Williams Syndrome (WS) presented with a two-month history of fatigue, weight loss, and bilateral ovarian masses. Histologic, immunophenotypic, and cytogenetic studies confirmed the diagnosis of Burkitt lymphoma (BL). While there is no established association between the two disorders, this is the third case in the literature of Burkitt lymphoma in a patient with Williams Syndrome.

Diagnostic challenges in a severely delayed infant with hypersomnolence, failure to thrive and arteriopathy: a unique case of gamma-hydroxybutyric aciduria and Williams syndrome

Metabolic work-up, pursued in a 5-month-old female infant with hypersomnolence, failure to thrive, and global developmental delay, led to the identification of gamma-hydroxybutyric aciduria (GHB). Succinic semialdehyde dehydrogenase deficiency (SSADH deficiency) was confirmed enzymatically and molecularly. Characteristic dysmorphic facies, cardiovascular anomalies, and hypercalcemia led to clinical suspicion of Williams-Beuren syndrome (WS), confirmed by cytogenetic studies. This rare occurrence of two unrelated genetic conditions highlights the importance of instituting comprehensive metabolic studies despite the presence of syndromic findings, even in the absence of other metabolic abnormalities that may be indicative of metabolic disease such as hyperammonemia, hypoglycemia, ketonuria, and metabolic acidosis.

Cellular and clinical impact of haploinsufficiency for genes involved in ATR signaling

Ataxia telangiectasia and Rad3-related (ATR) protein, a kinase that regulates a DNA damage-response pathway, is mutated in ATR-Seckel syndrome (ATR-SS), a disorder characterized by severe microcephaly and growth delay. Impaired ATR signaling is also observed in cell lines from additional disorders characterized by microcephaly and growth delay, including non-ATR-SS, Nijmegen breakage syndrome, and MCPH1 (microcephaly, primary autosomal recessive, 1)-dependent primary microcephaly. Here, we examined ATR-pathway function in cell lines from three haploinsufficient contiguous gene-deletion disorders--a subset of blepharophimosis-ptosis-epicanthus inversus syndrome, Miller-Dieker lissencephaly syndrome, and Williams-Beuren syndrome--in which the deleted region encompasses ATR, RPA1, and RFC2, respectively. These three genes function in ATR signaling. Cell lines from these disorders displayed an impaired ATR-dependent DNA damage response. Thus, we describe ATR signaling as a pathway unusually sensitive to haploinsufficiency and identify three further human disorders displaying a defective ATR-dependent DNA damage response. The striking correlation of ATR-pathway dysfunction with the presence of microcephaly and growth delay strongly suggests a causal relationship.