Homozygous Mutation of the FGFR1 Gene Associated with Congenital Heart Disease and 46,XY Disorder of Sex Development

Bart's syndrome associated with a disorder of sexual differentiation: An atypical presentation in a Cameroonian newborn

Bart's syndrome consists of congenital aplasia of the skin affecting only the lower limbs, associated with bullae over the skin and/or mucous membranes, as well as a nail anomaly. It is an extremely rare genetic disorder, which can be associated with other birth defects. We report the case of a newborn baby admitted at day 0 of life in the neonatal department, for multifocal skin detachment predominantly at the lower limbs. In addition, examination of the external genitalia revealed a clitoridomegaly genital bud measuring 14 mm, scrotalized and unfused genital bulges with the presence of 2 orifices. No gonad was palpated. The clinical diagnosis of Bart's syndrome associated with a disorder of sexual differentiation was retained. We hereby report the first case of Bart's syndrome described in Cameroon in association with a disorder of sexual differentiation.

Advances in genomic diagnosis of a large cohort of Egyptian patients with disorders of sex development

Disorders/differences of sex development (DSD) comprise a group of congenital disorders that affect the genitourinary tract and usually involve the endocrine and reproductive system. The aim of this work was to identify genetic variants responsible for disorders of human urogenital development in a cohort of Egyptian patients. This three-year study included 225 patients with various DSD forms, referred to the genetic DSD and endocrinology clinic, National Research Centre, Egypt. The patients underwent thorough clinical examination, hormonal and imaging studies, detailed cytogenetic and fluorescence in situ hybridization analysis, and molecular sequencing of genes known to commonly cause DSD including AR, SRD5A2, 17BHSD3, NR5A1, SRY, and WT1. Whole exome sequencing (WES) was carried out for 18 selected patients. The study revealed a high rate of sex chromosomal DSD (33%) with a wide array of cytogenetic abnormalities. Sanger sequencing identified pathogenic variants in 33.7% of 46,XY patients, while the detection rate of WES reached 66.7%. Our patients showed a different mutational profile compared with that reported in other populations with a predominance of heritable DSD causes. WES identified rare and novel pathogenic variants in NR5A1, WT1, HHAT, CYP19A1, AMH, AMHR2, and FANCA and in the X-linked genes ARX and KDM6A. In addition, digenic inheritance was observed in two of our patients and was suggested to be a cause of the phenotypic variability observed in DSD.

Understanding Heart Field Progenitor Cells for Modeling Congenital Heart Diseases

PURPOSE OF REVIEW

Heart development is a meticulously coordinated process that involves the specification of two distinct populations of cardiac progenitor cells, namely the first and the second heart field. Disruption of heart field progenitors can result in congenital heart defects. In this review, we aim to describe the signaling pathways and transcription factors that link heart field development and congenital heart disease.

RECENT FINDINGS

Single-cell transcriptomics, lineage-tracing mouse models, and stem cell-based in vitro modeling of cardiogenesis have significantly improved the spatiotemporal characterization of cardiac progenitors. Additionally, novel functional genomic studies have now linked more genetic variants with congenital heart disease. Dysregulation of cardiac progenitor cells causes malformations that can be lethal. Ongoing research will continue to shed light on cardiac morphogenesis and help us better understand and treat patients with congenital heart disease.

Novel Sex Chromosomes in 3 Cichlid Fishes from Lake Tanganyika

African cichlids are well known for their adaptive radiations, but it is now apparent that they also harbor an extraordinary diversity of sex chromosome systems. In this study, we sequenced pools of males and females from species in 3 different genera of cichlids from Lake Tanganyika. We then searched for regions that were differentiated following the patterns expected for sex chromosomes. We report 2 novel sex chromosomes systems, an XY system on LG19 in Tropheus sp. "black" and a ZW system on LG7 in Hemibates stenosoma. We also identify a ZW system on LG5 in Cyprichromis leptosoma that may be convergent with a system previously described in Lake Malawi cichlids. Our data also identify candidate single nucleotide polymorphisms for the blue/yellow tail color polymorphism observed among male C. leptosoma.

GENETICS IN ENDOCRINOLOGY: Approaches to molecular genetic diagnosis in the management of differences/disorders of sex development (DSD): position paper of EU COST Action BM 1303 ‘DSDnet’

The differential diagnosis of differences or disorders of sex development (DSD) belongs to the most complex fields in medicine. It requires a multidisciplinary team conducting a synoptic and complementary approach consisting of thorough clinical, hormonal and genetic workups. This position paper of EU COST (European Cooperation in Science and Technology) Action BM1303 ‘DSDnet’ was written by leading experts in the field and focuses on current best practice in genetic diagnosis in DSD patients. Ascertainment of the karyotpye defines one of the three major diagnostic DSD subclasses and is therefore the mandatory initial step. Subsequently, further analyses comprise molecular studies of monogenic DSD causes or analysis of copy number variations (CNV) or both. Panels of candidate genes provide rapid and reliable results. Whole exome and genome sequencing (WES and WGS) represent valuable methodological developments that are currently in the transition from basic science to clinical routine service in the field of DSD. However, in addition to covering known DSD candidate genes, WES and WGS help to identify novel genetic causes for DSD. Diagnostic interpretation must be performed with utmost caution and needs careful scientific validation in each DSD case.

Disorders of sex development

Normal sex development depends on the precise spatio-temporal sequence and coordination of mutually antagonistic activating and repressing factors. These factors regulate the commitment of the unipotential gonad into the binary pathways governing normal sex development. Typically, the presence of the SRY gene on the Y chromosome triggers the cascade of molecular events that lead to male sex development. Disorders of sex development comprise a heterogeneous group of congenital conditions associated with atypical development of internal and external genitalia. These disorders are generally attributed to deviations from the typical progression of sex development. Disorders of sex development can be classified into several categories including chromosomal, gonadal, and anatomic abnormalities. Genetic tools such as microarray analyses and next-generation sequencing techniques have identified novel genetic variants among patients with disorders of sexual development. Most importantly, patient management needs to be individualized, especially for decisions related to sex of rearing, surgical interventions, hormone treatment, and potential for fertility preservation.

A FGFR1 inhibitor patent review: progress since 2010

INTRODUCTION

FGFR1 is a well known molecular target for anticancer therapy. Many studies have proved that the regulation of FGFR1 activity is a promising therapeutic approach to treat a series of cancers. Therefore, the development of potent inhibitors has consequently become a key focus in the present drug discovery, and it is encouraging that several highly selective FGFR1 inhibitors have been identified from various sources in recent years. Areas covered: This article reviews patents and patent applications related to selective FGFR1 inhibitors published from 2010 to 2016. This summary highlights about 15 patents from different pharmaceutical companies and academic research groups. We used Baidu and NCBI search engines to find relevant patents as a search term. Expert opinion: In the past few years, considerable progress has been made in the identification and development of selective FGFR1 inhibitors in use. At present, at least 10 inhibitors of FGFR1 are in clinical trials, and several agents have shown encouraging results under experimental conditions. Given the fact that FGFR1 plays a crucial role in the regulation of cancer and other diseases, we hope that it will gain further attraction from pharmaceutical companies and encourage development of more novel, safe and efficient FGFR1 inhibitors in the future.

The role of next generation sequencing in understanding male and female sexual development: clinical implications

Next Generation Sequencing is revolutionising our understanding of variation in the human genome and as costs reduce the sequencing of patient's genomes is become more routine. Areas covered: Here, we review the current challenges in the field and some of the efforts that are underway to resolve them. We describe how these technologies are impacting on our understanding of human sex development and the profound clinical implications of these technologies on conditions such as Disorders of Sex Development (DSD). Expert commentary: The sheer wealth of genomic data is generating new challenges-some are technical such as variant calling, or predicting the functional consequence of a variant-whereas others are more profound, such as establishing the link between extensive genomic information and the clinical presentation. Predicting disease phenotypes from genetic sequences is often extremely difficult because the genotype-phenotype relationship has proven to be far more complex than anticipated.