Lymphoproliferative disorders in Sotos syndrome: observation of two cases

Lysine Methyltransferase NSD1 and Cancers: Any Role in Melanoma?

Simple Summary

Epigenetic events, which comprise post-translational modifications of histone tails or DNA methylation, control gene expression by altering chromatin structure without change in the DNA sequence. Histone tails modifications are driven by specific cellular enzymes such as histone methyltransferases or histone acetylases, which play a key role in regulating diverse biological processes. Their alteration may have consequences on growth and tumorigenesis.

Abstract

Epigenetic regulations, that comprise histone modifications and DNA methylation, are essential to processes as diverse as development and cancer. Among the histone post-translational modifications, lysine methylation represents one of the most important dynamic marks. Here, we focused on methyltransferases of the nuclear binding SET domain 1 (NSD) family, that catalyze the mono- and di-methylation of histone H3 lysine 36. We review the loss of function mutations of NSD1 in humans that are the main cause of SOTOS syndrome, a disease associated with an increased risk of developing cancer. We then report the role of NSD1 in triggering tumor suppressive or promoter functions according to the tissue context and we discuss the role of NSD1 in melanoma. Finally, we examine the ongoing efforts to target NSD1 signaling in cancers.

Acute lymphoblastic leukemia in Weaver syndrome

Weaver syndrome comprises pre- and postnatal overgrowth, accelerated osseous maturation, characteristic craniofacial appearance and developmental delay; it is a generally sporadic disorder, although autosomal dominant inheritance has been reported. Some of the manifestations characterize both the Weaver and Sotos syndrome, and distinction between the two is mainly by clinical examination and molecular testing. Most of the patients with Sotos syndrome have NSD1 gene deletions or mutations; however, the molecular basis of most of the Weaver syndrome patients is unknown. Patients with overgrowth syndromes have an increased frequency of tumors; the risk in Sotos syndrome patients has been estimated to be about 2-3%, with leukemia and lymphoma accounting for 44% of the malignancies. We report on a 4(1/2)-year-old girl with typical Weaver syndrome who developed acute lymphoblastic leukemia, an association not previously reported, and review the reported cases of Weaver syndrome patients who developed malignancies. Malignancy in Weaver syndrome has been reported previously in six patients. While searching the literature for all reported cases with Weaver syndrome and counting the cases with malignancy, we found that the frequency of tumors or hematologic malignancy was 10.9%. This is likely to be an overestimate, biased by failure to report cases without tumors and by over-reporting cases with this rare association. While the presence of acute lymphoblastic leukemia in our patient might be incidental, we cannot exclude a possible causative association between Weaver syndrome and hematologic malignancy.

Diagnosing Sotos syndrome in the setting of global developmental delay and macrocephaly

Sotos syndrome (cerebral gigantism) is characterized by macrocephaly, global developmental delay, characteristic facial dysmorphology, and a markedly advanced bone age. The purpose of this study was to describe the prevalence of Sotos syndrome in a consecutive series of patients with global developmental delay, which might modify our laboratory evaluation approach to this particular clinical situation. For a 10-year inclusive interval, the case records of all consecutive patients referred for global developmental delay in a single pediatric neurology practice were reviewed. Patients with macrocephaly were defined by an age- and gender-adjusted head circumference greater than or equal to the 98th percentile. Possible clinical factors associated with eventual diagnosis of Sotos syndrome in this group of macrocephalic children were tested with a two-tailed Fisher exact test. Of 261 children with global developmental delay, 18 (7%) had documented macrocephaly. Of these 18 children, 3 (17%) had an advanced bone age and were diagnosed with Sotos syndrome. In patients with global developmental delay and concomitant macrocephaly, Sotos syndrome is not uncommon. Assessment of bone age is a simple screening test for diagnosis of this entity and should be undertaken routinely in children with macrocephaly and global developmental delay even in the absence of other distinctive syndromic clinical features.

Risk of tumorigenesis in overgrowth syndromes: a comprehensive review

Overgrowth syndromes (OGS) comprise a heterogeneous group of disorders in which the main characteristic is that either weight, height, or head circumference is 2-3 standard deviations (SD) above the mean for sex and age. A striking feature of OGS is the risk of neoplasms. Here, the relative frequency of specific tumors in each OGS, topographic location, and age of appearance is determined by reviewing published cases. In some OGS (Perlman, Beckwith-Wiedemann, and Simpson-Golabi-Behmel syndromes and hemihyperplasia) more than 94% of tumors appeared in the abdomen usually before 10 years of age, mainly embryonal in type. In Perlman syndrome, only Wilms tumor has been recorded, whereas in Sotos syndrome, lympho-hematologic tumors are most frequent. Based on literature review, a specific schedule protocol for tumor screening is suggested for each OGS. A schedule with different intervals and specific tests is proposed for a more rational cost/benefit program for these disorders.

Cancer in Sotos syndrome: report of a patient with acute myelocytic leukemia and review of the literature

Sotos syndrome is a rare congenital disorder that is associated with various malignancies, including acute lymphoblastic leukemia and lymphomas. The NSD1 gene haploinsufficiency is associated with this syndrome. The authors report a case of acute myeloid leukemia developing in a child with Sotos syndrome. He was treated with standard chemotherapy and achieved sustained remission. On review of the literature, it was found that most malignancies in Sotos syndrome occur in childhood. In conclusion, because of their increased risk of developing malignancy, patients with Sotos syndrome should be followed closely for signs and symptoms of both hematologic and nonhematologic malignancies, at least during childhood.

Genetics of Sotos syndrome

PURPOSE OF REVIEW

Sotos syndrome (SoS) (OMIM #117550) is a childhood overgrowth syndrome characterized by excessive growth, distinctive craniofacial features, developmental delay, and advanced bone age. Recently, haploinsufficiency of the NSD1 gene has been identified as the major cause of SoS, with intragenic mutations or submicroscopic microdeletions being found in about 60 to 75% of clinically diagnosed patients with SoS.

RECENT FINDINGS

Recent reports provided much information about the genetic background of SoS, the NSD gene family, and genotype-phenotype correlation. They also added new perspectives in the discussion about a possible association between SoS and neoplasia.

SUMMARY

This review focuses on recent genetic developments in SoS. Clinical features and associated anomalies are reviewed in relation to possible functional roles of NSD1. Genotype-phenotype correlation between patients with SoS harboring either intragenic mutations or microdeletions is discussed as well as their implication for possible revision of the diagnostic criteria of SoS. Furthermore, future prospects in genetic research of SoS are presented.

Bilateral calcified ovarian fibromas in a patient with Sotos syndrome

OBJECTIVE

To present a case of bilateral calcified ovarian fibromas in Sotos syndrome (cerebral gigantism).

DESIGN

Descriptive case study.

SETTING

Mackay Memorial Hospital.

PATIENT(S)

A 26-year-old woman with Sotos syndrome and bilateral solid adnexal masses on gynecologic ultrasound.

INTERVENTION(S)

Surgical removal of an 8 x 6 x 6 cm left ovarian fibroma and a 3 x 2 x 2 cm right ovarian fibroma.

MAIN OUTCOME MEASURE(S)

Ultrasound.

RESULT(S)

Histopathologic examination revealed bilateral ovarian fibromas with extensive foci of calcification and occasional ossification.

CONCLUSION(S)

The presence of bilateral calcified ovarian fibromas in this patient with Sotos syndrome may reflect the effects of overgrowth in Sotos syndrome on ovarian tumorigenesis or may be a coincidence.

Recognition and management of childhood cancer syndromes: a systems approach

Recognition of congenital anomalies that predispose to childhood cancer allows for the institution of a cancer surveillance program, identification of relatives with increased cancer risk, and recurrence risk counseling. In this article, a systems approach to the diagnosis of 21 childhood cancer syndromes is set forth in the format of the pediatric physical examination. In the second part of this article, guidelines are presented for genetic testing, cancer screening, and genetic counseling for the 21 cancer syndromes.