A novel splice mutation in the TP53 gene associated with Leydig cell tumor and primitive neuroectodermal tumor

Precocious Puberty: Types, Pathogenesis and Updated Management

Precocious puberty (PP) means the appearance of secondary sexual characters before the age of eight years in girls and nine years in boys. Puberty is indicated in girls by the enlargement of the breasts (thelarche) in girls and in boys by the enlargement of the testes in either volume or length (testicular volume = 4 mL, testicular length = 25 mm, or both). Two types of PP are recognized - namely central PP (CPP) and peripheral PP (PPP). This paper aims to describe the clinical findings and laboratory workup of PP and to illustrate the new trends in the management of precocious sexual maturation. Gonadotropin-releasing hormone (GnRH)-independent type (PPP) refers to the development of early pubertal maturation not related to the central activation of the hypothalamic-pituitary-gonadal (HPG) axis. It is classified into genetic or acquired disorders. The most common forms of congenital or genetic causes involve McCune-Albright syndrome (MAS), familial male-limited PP, and congenital adrenal hyperplasia. The acquired causes include exogenous exposure to androgens, functioning tumors or cysts, and the pseudo-PP of profound primary hypothyroidism. On the other hand, CPP is the most common and it is a gonadotropin-dependent form. It is due to premature maturation of the HPG axis. CPP may occur as genetic alterations, such as MKRN3, DLK1, or KISS1;as a part of mutations in the epigenetic factors that regulate the HPG axis, such as Lin28b and let-7; or as a part of syndromes, central lesions such as hypothalamic hamartoma, and others. A full, detailed history and physical examination should be taken. Furthermore, several investigations should be conducted for both types of PP, including the estimation of serum gonadotropins such as luteinizing and follicle-stimulating hormones and sex steroids, in addition to a radiographic workup and thyroid function tests. Treatment depends on the type of PP: Long-acting GnRHa, either intramuscularly or implanted, is the norm of care for CPP management, while in PPP, especially in congenital adrenal hyperplasia, the goal of management is to suppress adrenal androgen secretion by glucocorticoids. In addition, anastrozole and letrozole - third-generation aromatase inhibitors - are more potent for MAS.

Transcriptome analysis of human Leydig cell tumours reveals potential mechanisms underlying its development

Leydig cell tumours are the most common sex cord-stromal tumours. In the last years, apparent increased incidence is noted while aetiology of the tumour is still unknown. Therefore, here, we focused on the genetics of Leydig cell tumours using the next-generation sequencing. Leydig cell micronodules were revealed in patients with azoospermia who were qualified for testicular biopsy. Complete gene set of Leydig cell tumours was compared with transcriptome of healthy Leydig cells obtained from donors. Bioinformatic analysis of the obtained sequencing data revealed alterations in expression of 219 transcripts. We showed, for the first time, that a significant proportion of differentially expressed genes is directly involved in regulation of apoptotic process, which downregulation might be important to Leydig cell tumour development. Additionally, we found a significant upregulation of heat shock protein genes that might be a unique feature of Leydig cell tumours when compared to other tumour types. Our study offers fundamental transcriptomic data for future studies on human Leydig cell tumour that are crucial to determine its causes. Moreover, presented here the in-depth analysis and discussion of alterations observed in tumour transcriptome may be important for the diagnosis and therapy of this pathology.

Clinical characteristics and registry-validated extended pedigrees of germline TP53 mutation carriers in Denmark

Introduction

TP53 mutation carrier (Li-Fraumeni Syndrome, LFS) cohort studies often suffer from lack of extensive pedigree exploration.

Methods

We performed a nation-wide exploration of TP53 mutation carrier families identified through all clinical genetics departments in Denmark. Pedigrees were expanded and verified using unique national person identification, cancer, cause of death, pathology, and church registries.

Results

We identified 30 confirmed, six obligate and 14 assumed carriers in 15 families harboring 14 different mutations, including five novel and three de novo germline mutations. All but two (96%) developed cancer by age 54 years [mean debut age; 29.1 y., median 33.0 y., n = 26 (17F, 9M), range 1–54 y]]. Cancer was the primary cause of all deaths [average age at death; 34.5 years]. Two tumors were identified through registry data alone. Two independent families harbored novel c.80delC mutations shown to be related through an ancestor born in 1907. This exhaustive national collection yielded markedly fewer TP53 mutation carriers than the 300–1,100 expected based on estimated background population frequencies.

Conclusion

Germline TP53 mutations in Denmark are likely to be drastically underdiagnosed despite their severe phenotype. Following recent advances in surveillance options of LFS patients, lack of pre-symptomatic testing may lead to the mismanagement of some individuals.

A Comprehensive Review of Pediatric Tumors and Associated Cancer Predisposition Syndromes

An understanding of the role of inherited cancer predisposition syndromes in pediatric tumor diagnoses continues to develop as more information is learned through the application of genomic technology. Identifying patients and their relatives at an increased risk for developing cancer is an important step in the care of this patient population. The purpose of this review is to highlight various tumor types that arise in the pediatric population and the cancer predisposition syndromes associated with those tumors. The review serves as a guide for recognizing genes and conditions to consider when a pediatric cancer referral presents to the genetics clinic.