The multi-faceted nature of 15 CFTR exonic variations: Impact on their functional classification and perspectives for therapy.

Background: The majority of variants of unknown clinical significance (VUCS) in the CFTR gene are missense variants. While change on the CFTR protein structure or function is often suspected, impact on splicing may be neglected. Such undetected splicing default of variants may complicate the interpretation of genetic analyses and the use of an appropriate pharmacotherapy.

Evaluation of somatic and/or germline mosaicism in congenital malformation of the eye.

Microphthalmia, Anophthalmia and Coloboma (MAC) form a spectrum of congenital eye malformations responsible for severe visual impairment. Despite the exploration of hundreds of genes by High-Throughput Sequencing (HTS), most of the patients remain without genetic diagnosis. One explanation could be the not yet demonstrated involvement of somatic mosaicism (undetected by conventional analysis pipelines) in those patients.

First step towards a consensus strategy for multi-locus diagnostic testing of imprinting disorders.

Background: Imprinting disorders, which affect growth, development, metabolism and neoplasia risk, are caused by genetic or epigenetic changes to genes that are expressed from only one parental allele. Disease may result from changes in coding sequences, copy number changes, uniparental disomy or imprinting defects. Some imprinting disorders are clinically heterogeneous, some are associated with more than one imprinted locus, and some patients have alterations affecting multiple loci.

Confirmation of FZD5 implication in a cohort of 50 patients with ocular coloboma.

Defects in optic fissure closure can lead to congenital ocular coloboma. This ocular malformation, often associated with microphthalmia, is described in various clinical forms with different inheritance patterns and genetic heterogeneity. In recent times, the identification of an increased number of genes involved in numerous cellular functions has led to a better understanding in optic fissure closure mechanisms.

Implication of non-coding PAX6 mutations in aniridia.

There is an increasing implication of non-coding regions in pathological processes of genetic origin. This is partly due to the emergence of sophisticated techniques that have transformed research into gene expression by allowing a more global understanding of the genome, both at the genomic, epigenomic and chromatin levels. Here, we implemented the analysis of PAX6, whose coding loss-of-function variants are mainly implied in aniridia, by studying its non-coding regions (untranslated regions, introns and cis-regulatory sequences).

Truncating Mutations in the Adhesion G Protein-Coupled Receptor G2 Gene ADGRG2 Cause an X-Linked Congenital Bilateral Absence of Vas Deferens.

In 80% of infertile men with obstructive azoospermia caused by a congenital bilateral absence of the vas deferens (CBAVD), mutations are identified in the cystic fibrosis transmembrane conductance regulator gene (CFTR). For the remaining 20%, the origin of the CBAVD is unknown. A large cohort of azoospermic men with CBAVD was retrospectively reassessed with more stringent selection criteria based on consistent clinical data, complete description of semen and reproductive excurrent ducts, extensive CFTR testing, and kidney ultrasound examination.

Incomplete penetrance of biallelic ALDH1A3 mutations.

The formation of a properly shaped eye is a complex developmental event that requires the coordination of many induction processes and differentiation pathways. Microphthalmia and anophthalmia (MA) represent the most severe defects that can affect the ocular globe during embryonic development. When genetic, these ocular disorders exhibit large genetic heterogeneity and extreme variable expressivity.

Highly restricted deletion of the SNORD116 region is implicated in Prader-Willi Syndrome.

The SNORD116 locus lies in the 15q11-13 region of paternally expressed genes implicated in Prader-Willi Syndrome (PWS), a complex disease accompanied by obesity and severe neurobehavioural disturbances. Cases of PWS patients with a deletion encompassing the SNORD116 gene cluster, but preserving the expression of flanking genes, have been described. We report a 23-year-old woman who presented clinical criteria of PWS, including the behavioural and nutritional features, obesity, developmental delay and endocrine dysfunctions with hyperghrelinemia.

Mutations in WNT10A are frequently involved in oligodontia associated with minor signs of ectodermal dysplasia.

Ectodermal dysplasias (ED) are a clinically and genetically heterogeneous group of hereditary disorders that have in common abnormal development of ectodermal derivatives. Hypohidrotic ectodermal dysplasia (HED) is characterized by abnormal development of eccrine sweat glands, hair, and teeth. The X-linked form of the disease, caused by mutations in the EDA gene, represents the majority of patients with the hypohidrotic form.

Proximal 15q familial euchromatic variant and PWS/AS critical region duplication in the same patient: a cytogenetic pitfall.

Cytogenetically detectable elongation of the 15q proximal region can be associated with Prader-Willi/Angelman critical region interstitial duplications or with inherited juxtacentromeric euchromatic variants. The first category has been reported in association with developmental delay and autistic disorders. These pathogenic recurrent duplications are more frequently of maternal origin and originate from unequal meiotic crossovers between chromosome 15 low-copy repeats.

Beckwith-Wiedemann-like macroglossia and 18q23 haploinsufficiency.

Beckwith-Wiedemann syndrome (BWS) is an overgrowth condition with tumor proclivity linked to a genetic imbalance of a complex imprinted region in 11p15.5. A female child with features fitting in with the BWS diagnostic framework and an apparent loss of imprinting (LOI) of the IGF2 gene in 11p15.

Epigenotyping as a tool for the prediction of tumor risk and tumor type in patients with Beckwith-Wiedemann syndrome (BWS).

Objectives: Patients with Beckwith-Wiedemann syndrome (BWS) have a risk of 7.5% to 10% of developing childhood tumors, 60% of which are Wilms' tumors. Aberrant methylation of two distinct clusters of imprinted genes on chromosome 11p15 is detected in approximately 70% of BWS cases.

A case report in favor of a multistep adrenocortical tumorigenesis.

The mechanisms of adrenocortical tumorigenesis are still not fully understood. Data from clonal analysis, comparative genomic hybridization, and allelotyping suggest that it involves a multistep process during which several genetic defects are progressively acquired, leading to the malignant transformation. The events involved in the first steps of this process are not well known, and most of the abnormalities described in adrenocortical tumors to date are associated with the malignant phenotype.

Expression of the gene for the alpha-subunit of inhibin in human adrenocortical tumours.

Background: To determine whether the pathogenesis of human adrenocortical tumours is associated with variations of inhibin expression, we assayed the mRNA of the alpha-subunit of inhibin in 5 normal adrenals and 48 adrenocortical tumours, including 10 paediatric tumours.

Results: mRNA of alpha-subunit of inhibin was detected in all adrenocortical tissues. It was similarly abundant in the three pathological groups of adult tumours (benign, suspect and malignant) and in normal adrenal tissues, irrespective of the hormonal pattern.

Molecular markers and long-term recurrences in a large cohort of patients with sporadic adrenocortical tumors.

Genetic alterations, such as loss of heterozygosity (LOH) at the 17p13 and 11p15 loci and overexpression of the insulin-like growth factor (IGF)-II gene, are associated with the malignant phenotype in sporadic adrenocortical tumors. A high risk of recurrence after surgery for adrenocortical tumors is predicted in cases with regional invasion or distant metastases. However, patients with localized tumors also have a high risk of recurrence.

Analysis of the methylation status of the KCNQ1OT and H19 genes in leukocyte DNA for the diagnosis and prognosis of Beckwith-Wiedemann syndrome.

Beckwith-Wiedemann syndrome (BWS) is an overgrowth disorder involving developmental abnormalities, tissue and organ hyperplasia and an increased risk of embryonal tumours (most commonly Wilms tumour). This multigenic disorder is caused by dysregulation of the expression of imprinted genes in the 11p15 chromosomal region. Molecular diagnosis of BWS is currently difficult, mostly due to the large spectrum of genetic and epigenetic abnormalities.

[Involvement of the IGF system in the pathogenesis of adrenocortical tumors].

Adrenocortical carcinoma remains a challenge for the therapeutist; prognosis is ominous. Various abnormalities playing a pathogenetic role have been recently described in adrenocortical tumors. Among them, dysregulation of the IGF system and imprinting mistakes at the 11p15 locus play a determining role in malignant transformation of adrenocortical cells.