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Introduction: Primary ciliary dyskinesia (PCD) is a rare, progressive, inherited ciliopathic disorder, which is incurable and frequently complicated by the development of bronchiectasis. There are few randomised controlled trials (RCTs) involving children and adults with PCD and thus evidence of efficacy for interventions are usually extrapolated from people with cystic fibrosis. Our planned RCT seeks to address some of these unmet needs by employing a currently prescribed (but unapproved for long-term use in PCD) macrolide antibiotic (azithromycin) and a novel mucolytic agent (erdosteine). The primary aim of our RCT is to determine whether regular oral azithromycin and erdosteine over a 12-month period reduces acute respiratory exacerbations among children and adults with PCD. Our primary hypothesis is that: people with PCD who regularly use oral azithromycin and/or erdosteine will have fewer exacerbations than those receiving the corresponding placebo medications. Our secondary aims are to determine the effect of the trial medications on PCD-specific quality-of-life (QoL) and other clinical outcomes (lung function, time-to-next exacerbation, hospitalisations) and nasopharyngeal bacterial carriage and antimicrobial resistance. Methods and analysis: We are currently undertaking a multicentre, double-blind, double-dummy RCT to evaluate whether 12 months of azithromycin and/or erdosteine is beneficial for children and adults with PCD. We plan to recruit 104 children and adults with PCD to a parallel, 2×2 partial factorial superiority RCT at five sites across Australia. Our primary endpoint is the rate of exacerbations over 12 months. Our main secondary outcomes are QoL, lung function and nasopharyngeal carriage by respiratory bacterial pathogens and their associated azithromycin resistance. Ethics and dissemination: Our RCT is conducted in accordance with Good Clinical Practice and the Australian legislation and National Health and Medical Research C

Lung cancer is the commonest cause of cancer deaths worldwide. Although strongly associated with smoking, predisposition to lung cancer is also heritable, with multiple common risk variants identified. Rarely, dominantly inherited non-small-cell lung cancer (NSCLC) has been reported due to somatic mutations in EGFR/ErbB1 and ERBB2. Germline exome sequencing was performed in a multi-generation family with autosomal dominant NSCLC, including an affected child. Tumour samples were also sequenced. Full-length wild-type (wtErbB3) and mutant ERBB3 (mutErbB3) constructs were transfected into HeLa cells. Protein expression, stability, and subcellular localization were assessed, and cellular proliferation, pAkt/Akt and pERK levels determined. A novel germline variant in ERBB3 (c.1946 T > G: p.Iso649Arg), coding for receptor tyrosine-protein kinase erbB-3 (ErbB3), was identified, with appropriate segregation. There was no loss-of-heterozygosity in tumour samples. Both wtErbB3 and mutErbB3 were stably expressed. MutErbB3-transfected cells demonstrated an increased ratio of the 80 kDa form (which enhances proliferation) compared with the full-length (180 kDa) form. MutErbB3 and wtErbB3 had similar punctate cytoplasmic localization pre-and post-epidermal growth factor stimulation; however, epidermal growth factor receptor (EGFR) levels decreased faster post-stimulation in mutErbB3-transfected cells, suggesting more rapid processing of the mutErbB3/EGFR heterodimer. Cellular proliferation was increased in mutErbB3-transfected cells compared with wtErbB3 transfection. MutErbB3-transfected cells also showed decreased pAkt/tAkt ratios and increased pERK/tERK 30 min post-stimulation compared with wtErbB3 transfection, demonstrating altered signalling pathway activation. Cumulatively, these results support this mutation as tumorogenic. This is the first reported family with a germline ERBB3 mutation causing heritable NSCLC, furthering understanding of the ErbB family pathway in onc

Context: Pathogenic germline MAX variants are associated with pheochromocytoma and paraganglioma (PPGL), pituitary neuroendocrine tumors and, possibly, other endocrine and nonendocrine tumors. Objective: To report 2 families with germline MAX variants, pheochromocytomas (PCs) and multiple other tumors. Methods: Clinical, genetic, immunohistochemical, and functional studies at University hospitals in Australia on 2 families with germline MAX variants undergoing usual clinical care. The main outcome measures were phenotyping; germline and tumor sequencing; immunohistochemistry of PC and other tumors; functional studies of MAX variants. Results: Family A has multiple individuals with PC (including bilateral and metastatic disease) and 2 children (to date, without PC) with neuroendocrine tumors (paravertebral ganglioneuroma and abdominal neuroblastoma, respectively). One individual has acromegaly; immunohistochemistry of PC tissue showed positive growth hormone-releasing hormone staining. Another individual with previously resected PCs has pituitary enlargement and elevated insulin-like growth factor (IGF-1). A germline MAX variant (c.200C>A, p.Ala67Asp) was identified in all individuals with PC and both children, with loss of heterozygosity in PC tissue. Immunohistochemistry showed loss of MAX staining in PCs and other neural crest tumors. In vitro studies confirmed the variant as loss of function. In Family B, the proband has bilateral and metastatic PC, prolactin-producing pituitary tumor, multigland parathyroid adenomas, chondrosarcoma, and multifocal pulmonary adenocarcinomas. A truncating germline MAX variant (c.22G>T, p.Glu8∗) was identified. Conclusion: Germline MAX mutations are associated with PCs, ganglioneuromas, neuroblastomas, pituitary neuroendocrine tumors, and, possibly, parathyroid adenomas, as well as nonendocrine tumors of chondrosarcoma and lung adenocarcinoma, suggesting MAX is a novel multiple endocrine neoplasia gene.

Background: Recent genome-wide association meta-analysis for melanoma doubled the number of previously identified variants. We assessed the performance of an updated polygenic risk score (PRS) in a population of older individuals, where melanoma incidence and cumulative ultraviolet radiation exposure is greatest. Methods: We assessed a PRS for cutaneous melanoma comprising 55 variants in a prospective study of 12 712 individuals in the ASPirin in Reducing Events in the Elderly Trial. We evaluated incident melanomas diagnosed during the trial and prevalent melanomas diagnosed preenrolment (self-reported). Multivariable models examined associations between PRS as a continuous variable (per SD) and categorical (low-risk [0%-20%], medium-risk [21%-80%], high-risk [81%-100%] groups) with incident melanoma. Logistic regression examined the association between PRS and prevalent melanoma. Results: At baseline, mean participant age was 75 years; 55.0% were female, and 528 (4.2%) had prevalent melanomas. During follow-up (median = 4.7 years), 120 (1.0%) incident cutaneous melanomas occurred, 98 of which were in participants with no history. PRS was associated with incident melanoma (hazard ratio = 1.46 per SD, 95% confidence interval [CI] = 1.20 to 1.77) and prevalent melanoma (odds ratio [OR] = 1.55 per SD, 95% CI = 1.42 to 1.69). Participants in the highest-risk PRS group had increased risk compared with the low-risk group for incident melanoma (OR = 2.51, 95% CI = 1.28 to 4.92) and prevalent melanoma (OR = 3.66, 95% CI = 2.69 to 5.05). When stratifying by sex, only males had an association between the PRS and incident melanoma, whereas both sexes had an association between the PRS and prevalent melanoma. Conclusions: A genomic risk score is associated with melanoma risk in older individuals and may contribute to targeted surveillance.

Novel anabolic drug targets are needed to treat osteoporosis. Having established a large national cohort with unexplained high bone mass (HBM), we aimed to identify a novel monogenic cause of HBM and provide insight into a regulatory pathway potentially amenable to therapeutic intervention. We investigated a pedigree with unexplained HBM in whom previous sequencing had excluded known causes of monogenic HBM. Whole exome sequencing identified a rare (minor allele frequency 0.0023), highly evolutionarily conserved missense mutation in SMAD9 (c.65T>C, p.Leu22Pro) segregating with HBM in this autosomal dominant family. The same mutation was identified in another two unrelated individuals both with HBM. In silico protein modeling predicts the mutation severely disrupts the MH1 DNA-binding domain of SMAD9. Affected individuals have bone mineral density (BMD) Z-scores +3 to +5, mandible enlargement, a broad frame, torus palatinus/mandibularis, pes planus, increased shoe size, and a tendency to sink when swimming. Peripheral quantitative computed tomography (pQCT) measurement demonstrates increased trabecular volumetric BMD and increased cortical thickness conferring greater predicted bone strength; bone turnover markers are low/normal. Notably, fractures and nerve compression are not found. Both genome-wide and gene-based association testing involving estimated BMD measured at the heel in 362,924 white British subjects from the UK Biobank Study showed strong associations with SMAD9 (PGWAS = 6 × 10−16; PGENE = 8 × 10−17). Furthermore, we found Smad9 to be highly expressed in both murine cortical bone–derived osteocytes and skeletal elements of zebrafish larvae. Our findings support SMAD9 as a novel HBM gene and a potential novel osteoanabolic target for osteoporosis therapeutics. SMAD9 is thought to inhibit bone morphogenetic protein (BMP)-dependent target gene transcription to reduce osteoblast activity. Thus, we hypothesize S

Background: Marfan syndrome (MFS) is a dominant monogenic disorder caused by mutations in fibrillin 1 (FBN1). Rarely, compound heterozygosity for FBN1 mutations has been described. Methods: A large kindred with MFS was assessed clinically over decades, and genetically using exome and/or Sanger sequencing. Results: A previously identified FBN1 missense variant (p.Tyr754Cys) was confirmed in all subjects with MFS. An additional variant (p.Met2273Thr), previously associated with incomplete MFS, was identified in three siblings. These three compound heterozygous individuals had aortic dilatation at early age (all <30 years): one also had cerebral and ocular aneurysms; and one, who had undergone surgical repair aged 18 years, died from aortic dissection at 31 years. In contrast, their heterozygous father (p.Tyr754Cys) with MFS died at 57 years (myocardial infarction) without requiring surgical intervention and one heterozygous (p.Tyr754Cys) sibling has aortic dilatation presenting >40 years but not requiring surgical intervention. Another heterozygous (p.Tyr754Cys) sibling did require aortic root repair (28 years). The heterozygous (p.Met2273Thr) mother had aortic dilatation diagnosed at age 68 years but has not required surgical repair. Conclusion: Although compound heterozygosity or homozygosity is rare in MFS, it should be considered when there is an unusually severe phenotype in a subset of family members.

The genetic causes of multiple congenital anomalies are incompletely understood. Here, we report novel heterozygous predicted loss-of-function (LoF) and predicted damaging missense variants in the WW domain binding protein 11 (WBP11) gene in seven unrelated families with a variety of overlapping congenital malformations, including cardiac, vertebral, tracheo-esophageal, renal and limb defects. WBP11 encodes a component of the spliceosome with the ability to activate pre-messenger RNA splicing. We generated a Wbp11 null allele in mouse using CRISPR-Cas9 targeting. Wbp11 homozygous null embryos die prior to E8.5, indicating that Wbp11 is essential for development. Fewer Wbp11 heterozygous null mice are found than expected due to embryonic and postnatal death. Importantly, Wbp11 heterozygous null mice are small and exhibit defects in axial skeleton, kidneys and esophagus, similar to the affected individuals, supporting the role of WBP11 haploinsufficiency in the development of congenital malformations in humans. LoF WBP11 variants should be considered as a possible cause of VACTERL association as well as isolated Klippel-Feil syndrome, renal agenesis or esophageal atresia.

Causal attributions are important determinants of how health threats are processed and affect health-related behaviors. To date, there has been no research on causal attributions in genetic conditions in Aboriginal Australians. Forty members of a large Aboriginal Australian family with Marfan syndrome (MFS) were invited to participate in an ethically approved study exploring causal attributions, including perceived causes of phenotypic variability within the family. Eighteen individuals consented to conduct semi-structured qualitative interviews, which were recorded, transcribed verbatim and analyzed thematically. Most participants knew that MFS was genetic, but there were diverse theories about inheritance, including beliefs that it skipped generations, was affected by birth order and/or gender, and that it co-occurred with inheritance of blue eyes within this family. The mutation was thought to have been inherited from British settlers and initially triggered by disease or diet. Factors believed to modify disease severity included other genes and lifestyle factors, particularly alcohol and substance abuse and stress. Generally, this family did not endorse “blaming” chance or a higher power for phenotypic variability, though some felt that the spirits or a deity may have played a role. In conclusion, although participants knew MFS was a genetic condition, many speculated about the role of non-genetic causes in initiating the original mutation; and the gene-environment interaction was thought to affect severity. This study demonstrates a successful approach for exploring causal attributions in other genetic conditions in First Australians.

Genetic testing is used widely for diagnostic, carrier and predictive testing in monogenic diseases. Until recently, there were no genetic testing options available for multifactorial complex diseases like heart disease, diabetes and cancer. Genome-wide association studies (GWAS) have been invaluable in identifying single-nucleotide polymorphisms (SNPs) associated with increased or decreased risk for hundreds of complex disorders. For a given disease, SNPs can be combined to generate a cumulative estimation of risk known as a polygenic risk score (PRS). After years of research, PRSs are increasingly used in clinical settings. In this article, we will review the literature on how both genome-wide and restricted PRSs are developed and the relative merit of each. The validation and evaluation of PRSs will also be discussed, including the recognition that PRS validity is intrinsically linked to the methodological and analytical approach of the foundation GWAS together with the ethnic characteristics of that cohort. Specifically, population differences may affect imputation accuracy, risk magnitude and direction. Even as PRSs are being introduced into clinical practice, there is a push to combine them with clinical and demographic risk factors to develop a holistic disease risk. The existing evidence regarding the clinical utility of PRSs is considered across four different domains: Informing population screening programs, guiding therapeutic interventions, refining risk for families at high risk, and facilitating diagnosis and predicting prognostic outcomes. The evidence for clinical utility in relation to five well-studied disorders is summarized. The potential ethical, legal and social implications are also highlighted.