Virilization at puberty in adolescent girls may reveal a 46,XY disorder of sexual development

Although hyperandrogenism is a frequent cause of consultation in adolescent girls, more severe forms with virilization must lead to suspicion of an adrenal or ovarian tumor. However, they may also reveal a 46,XY disorder of sexual development (DSD). Here, we describe four adolescent girls referred for pubertal virilization and in whom we diagnosed a 46,XY DSD. We performed gene mutation screening by Sanger sequencing (all patients) and by next-generation sequencing (NGS) in patient #4. We identified new heterozygous NR5A1 gene variants in patients #1 and #2 and a homozygous SRD5A2 gene deletion in patient #3. Patient #4 received a diagnosis of complete androgen insensitivity in childhood; however, due the unusual pubertal virilization, we completed the gene analysis by NGS that revealed two heterozygous HSD17B3 variants. This work underlines the importance of considering the hypothesis of 46,XY DSD in adolescent girls with unexplained virilization at puberty.

Information needs on nutrition in link to cancer prevention among cancer patients, high-risk individuals and general population - A national cross-sectional study

BACKGROUND & AIMS

Nutrition is one of the fundamentals of cancer prevention. Knowing what are the patients' needs and beliefs in terms of "nutrition and cancer" information helps tailor future nutritional interventions. The aim of this study was to evaluate specific information needs about "nutrition in relation to cancer prevention", including primary and tertiary prevention, among cancer patients, cancer-free individuals, and genetic high cancer risk individuals.

METHODS

This online survey was shared within two large National cancer social networks and proposed to all attendees and carers of a comprehensive cancer center.

RESULTS

2887 individuals answered the survey (of whom 33% were cancer patients, 13% high-risk individuals and 55% participants of the general population). More than 80% of participants were women, had at least a high school degree. Median body mass index was 23.2 kg/m². Eleven percent (n = 321) were following a diet, mostly low carbohydrate and weight-loss diets. Around 70% of all categories felt they lacked information on nutrition and cancer interplays. Only 12% of cancer patients (n = 108) considered they had received enough information on nutrition during their care pathway. A majority of participants agreed that food can modify cancer risk (93%, n = 2526) and 66% (n = 1781) considered that nutrition should be personalized according to the risk of cancer. Only twenty-nine percent (n = 792) believed that eating 5 fruits and vegetables a day was enough to avoid cancer, but 64% (n = 1720) thought that dietary supplements could help obtain a better health. All proposed nutrition topics were considered important by the participants.

CONCLUSIONS

Although cancer patients and cancer-free respondents, whether at high risk of cancer or not, share a common broad interest on the interplay between nutrition and cancer and seek after more information on this topic, some false beliefs are observed. Healthcare providers could successfully propose more evidence-based information to these populations.

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.

METHODS

We selected 15 variants suspected to impact CFTR splicing after in silico predictions on 319 missense variants (214 VUCS), reported in the CFTR-France database. Six specialized laboratories assessed the impact of nucleotide substitutions on splicing (minigenes), mRNA expression levels (quantitative PCR), synthesis and maturation (western blot), cellular localization (immunofluorescence) and channel function (patch clamp) of the CFTR protein. We also studied maturation and function of the truncated protein, consecutive to in-frame aberrant splicing, on additional plasmid constructs.

RESULTS

Six of the 15 variants had a major impact on CFTR splicing by in-frame (n = 3) or out-of-frame (n = 3) exon skipping. We reclassified variants into: splicing variants; variants causing a splicing defect and the impairment of CFTR folding and/or function related to the amino acid substitution; deleterious missense variants that impair CFTR folding and/or function; and variants with no consequence on the different processes tested.

CONCLUSION

The 15 variants have been reclassified by our comprehensive approach of in vitro experiments that should be used to properly interpret very rare exonic variants of the CFTR gene. Targeted therapies may thus be adapted to the molecular defects regarding the results of laboratory experiments.

Hedgehog pathway and its inhibitors in chronic obstructive pulmonary disease (COPD)

COPD affects millions of people and is now ranked as the third leading cause of death worldwide. This largely untreatable chronic airway disease results in irreversible destruction of lung architecture. The small lung hypothesis is now supported by epidemiological, physiological and clinical studies. Accordingly, the early and severe COPD phenotype carries the most dreadful prognosis and finds its roots during lung growth. Pathophysiological mechanisms remain poorly understood and implicate individual susceptibility (genetics), a large part of environmental factors (viral infections, tobacco consumption, air pollution) and the combined effects of those triggers on gene expression. Genetic susceptibility is most likely involved as the disease is severe and starts early in life. The latter observation led to the identification of Mendelian inheritance via disease-causing variants of SERPINA1 - known as the basis for alpha-1 anti-trypsin deficiency, and TERT. In the last two decades multiple genome wide association studies (GWAS) identified many single nucleotide polymorphisms (SNPs) associated with COPD. High significance SNPs are located in 4q31 near HHIP which encodes an evolutionarily highly conserved physiological inhibitor of the Hedgehog signaling pathway (HH). HHIP is critical to several in utero developmental lung processes. It is also implicated in homeostasis, injury response, epithelial-mesenchymal transition and tumor resistance to apoptosis. A few studies have reported decreased HHIP RNA and protein levels in human adult COPD lungs. HHIP^+/- murine models led to emphysema. HH pathway inhibitors, such as vismodegib and sonidegib, are already validated in oncology, whereas other drugs have evidenced in vitro effects. Targeting the Hedgehog pathway could lead to a new therapeutic avenue in COPD. In this review, we focused on the early and severe COPD phenotype and the small lung hypothesis by exploring genetic susceptibility traits that are potentially treatable, thus summarizing promising therapeutics for the future.

CFTR gene variants, epidemiology and molecular pathology

Pathogenic variants of the CFTR gene are responsible for a broad phenotypic spectrum characterized by malfunction of some exocrine tissues, with an autosomal recessive mode of inheritance. More than 2,000 variants, distributed throughout the CFTR gene, have been identified, with different effects on the gene and protein expression and function. Genotype-phenotype correlation studies have associated severe variants with a typical multi-organ form of cystic fibrosis, while mild variants are involved in monosymptomatic or adult-onset diseases, called CFTR-related disorders. However, the interpretation of rare variants remains challenging. This review presents an overview of the epidemiology of CFTR variants worldwide and in France and describes the functional classification. Finally, some frequent cystic fibrosis-causing and mild CFTR variants are used as example to depict the molecular pathology of the CFTR locus. Finally, we give the recommendations concerning nomenclature and classification that are useful for appropriate genetic counseling. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Penetrance is a critical parameter for assessing the disease liability of CFTR variants

BACKGROUND

Major issues of newborn screening (NBS) for CF are the assessment of disease liability of variants and of the penetrance of clinical CF, notably in inconclusive diagnosis. The penetrance of CF is defined as the risk of a particular genotype to lead to a CF phenotype.

METHODS

We aimed to get insight into the penetrance of CF for fifteen CFTR variants: 5 frequent CF-causing and 10 classified as of varying clinical consequence (VCC) or associated with a CFTR-related disorder (CFTR-RD) in CFTR2 or CFTR-France databases. The penetrance was approached by: (1) comparison of variant allelic frequencies in CF patients (CFTR2) and in the general population; (2) estimation of the likelihood of a positive NBS test for the 14 compound heterozygous with F508del and the F508del homozygous genotypes, defined as the ratio of detected/expected number of neonates with a given genotype in the 2002-2017 period.

RESULTS

A full penetrance was observed for severe CF-causing variants. Five variants were more frequently found in the general population than in CF patients: TG11T5, TG12T5, TG13T5, L997F and R117H;T7. The likelihood of a positive NBS test was 0.03% for TG11T5, 0.3% for TG12T5, 1.9% for TG13T5, 0.6% for L997F, 11.7% for D1152H, and 17.8% for R117H;T7. Penetrance varied greatly for variants with discrepant classification between CFTR2 and CFTR-France: 5.1% for R117C, 12.3% for T338I, 43.5% for D110H and 52.6% for L206W.

CONCLUSION

These results illustrate the contribution of genetics population data to assess the disease liability of variants for diagnosis and genetic counselling purposes.

Functional characterization and phenotypic spectrum of three recurrent disease-causing deep intronic variants of the CFTR gene

BACKGROUND

The CFTR genotype remains incomplete in 1% of Cystic Fibrosis (CF) cases, because only one or no disease-causing variants is detected after extended analysis. This fraction is probably higher in CFTR-Related Disorders (CFTR-RD). Deep-intronic CFTR variants are putative candidates to fill this gap. However, the recurrence, phenotypic spectrum and full molecular characterization of newly reported variants are unknown.

METHODS

Minigenes and analysis of CFTR transcripts in nasal epithelial cells were used to determine the impact on CFTR splicing of intronic variants that we previously identified by next generation sequencing of the whole CFTR locus. Phenotypic data were collected in 19 patients with CF and CFTR-RD, in whom one of the deep intronic variants has been detected.

RESULTS

Three deep-intronic variants promoted the inclusion of pseudo-exons (PE) in the CFTR transcript, hindering the synthesis of a functional protein. The c.2989-313A > T variant, detected in four patients with CF or CFTR-RD from three different families, led to the inclusion of a 118 bp PE. The c.3469-1304C > G variant promoted the inclusion of a 214 bp-PE and was identified in five patients with CF from four families. Haplotype analysis confirmed that this variant was associated with one CF chromosome of African origin. The most represented variant in our cohort was the c.3874-4522A > G, detected in 10 patients with various phenotypes, from male infertility to CF with pancreatic insufficiency.

CONCLUSION

These three deep intronic CFTR variants are associated with a large phenotypic spectrum, including typical CF. They should be included in CF diagnostic testing and carrier screening strategies.