Genome sequencing reveals underdiagnosis of primary ciliary dyskinesia in bronchiectasis

BACKGROUND

Bronchiectasis can result from infectious, genetic, immunological and allergic causes. 60-80% of cases are idiopathic, but a well-recognised genetic cause is the motile ciliopathy, primary ciliary dyskinesia (PCD). Diagnosis of PCD has management implications including addressing comorbidities, implementing genetic and fertility counselling and future access to PCD-specific treatments. Diagnostic testing can be complex; however, PCD genetic testing is moving rapidly from research into clinical diagnostics and would confirm the cause of bronchiectasis.

METHODS

This observational study used genetic data from severe bronchiectasis patients recruited to the UK 100,000 Genomes Project and patients referred for gene panel testing within a tertiary respiratory hospital. Patients referred for genetic testing due to clinical suspicion of PCD were excluded from both analyses. Data were accessed from the British Thoracic Society audit, to investigate whether motile ciliopathies are underdiagnosed in people with bronchiectasis in the UK.

RESULTS

Pathogenic or likely pathogenic variants were identified in motile ciliopathy genes in 17 (12%) out of 142 individuals by whole-genome sequencing. Similarly, in a single centre with access to pathological diagnostic facilities, 5-10% of patients received a PCD diagnosis by gene panel, often linked to normal/inconclusive nasal nitric oxide and cilia functional test results. In 4898 audited patients with bronchiectasis, <2% were tested for PCD and <1% received genetic testing.

CONCLUSIONS

PCD is underdiagnosed as a cause of bronchiectasis. Increased uptake of genetic testing may help to identify bronchiectasis due to motile ciliopathies and ensure appropriate management.

De Novo SOX6 Variants Cause a Neurodevelopmental Syndrome Associated with ADHD, Craniosynostosis, and Osteochondromas

SOX6 belongs to a family of 20 SRY-related HMG-box-containing (SOX) genes that encode transcription factors controlling cell fate and differentiation in many developmental and adult processes. For SOX6, these processes include, but are not limited to, neurogenesis and skeletogenesis. Variants in half of the SOX genes have been shown to cause severe developmental and adult syndromes, referred to as SOXopathies. We here provide evidence that SOX6 variants also cause a SOXopathy. Using clinical and genetic data, we identify 19 individuals harboring various types of SOX6 alterations and exhibiting developmental delay and/or intellectual disability; the individuals are from 17 unrelated families. Additional, inconstant features include attention-deficit/hyperactivity disorder (ADHD), autism, mild facial dysmorphism, craniosynostosis, and multiple osteochondromas. All variants are heterozygous. Fourteen are de novo, one is inherited from a mosaic father, and four offspring from two families have a paternally inherited variant. Intragenic microdeletions, balanced structural rearrangements, frameshifts, and nonsense variants are predicted to inactivate the SOX6 variant allele. Four missense variants occur in residues and protein regions highly conserved evolutionarily. These variants are not detected in the gnomAD control cohort, and the amino acid substitutions are predicted to be damaging. Two of these variants are located in the HMG domain and abolish SOX6 transcriptional activity in vitro. No clear genotype-phenotype correlations are found. Taken together, these findings concur that SOX6 haploinsufficiency leads to a neurodevelopmental SOXopathy that often includes ADHD and abnormal skeletal and other features.

Triticum vulgare mouthwashes (TVM) for patients (pts) with oral mucositis (OM) induced by chemotherapy and chemoradiotherapy (ONCOLGroup study)

e20570

Background: OM is a frequent complication of cancer therapy in Colombia. Triticum vulgare has been reported to effectively treat mucosal and skin disturbances. Methods: To evaluate the safety and efficacy of TVM for the control of OM induced by chemoradiotherapy in pts with head and neck cancer (HNC) and by chemotherapy in pts with haematological malignancies (HM). Thirty-one pts received TVM delivered in a spray four times daily to the whole oral cavity until the OM being resolved. The primary endpoint was the OM grade evaluated daily using the Nebraska scale (NS). Secondary endpoints were OM duration, weight loss, pain and TVM tolerance; the latter two were evaluated using a visual analogue scale (VAS). Results were compared with data from 42 pts with OM treated with saline mouthwashes (SM) in a previous clinical trial. Results: Nineteen pts had HM and 12 had HNC; those with HM developed OM on day 9 of chemotherapy (range, 7–14), whilst those having HNC did so towards day 17 of chemoradiation (range, 13–26). Using NS 38% of pts developed GI OM, 46% GII OM and 16% GIII OM. Moderate and severe OM occurred more frequently amongst HNC pts (8 vs 1, p = 0.047), mean OM duration in HNC pts was 12±4.5 days, whilst it was 7 ±3 days (p = 0.047) in pts with HM. Median OM duration in pts treated with TVM was 5.4 days (range, 2–9) vs 7 days (range 1–17) for pts treated with SM (p = 0.048). TVM appears to reduce weight loss, especially in pts with HNC (p = 0.058); however, no changes were documented regarding saliva characteristics and production, mucosal bleeding and voice properties. Evaluation of pain did not reveal differences between the groups (VAS 5.5 for the TV compared to VAS 6.2 for SM; p = 0.27) but the proportion of pts suffering from pain VAS≥7 differed between both populations (8% TV vs 23% SM; p = 0.043). There are no significant adverse events with TVM. Conclusions: TVM is safe and has therapeutic activity against OM. Further phase III study is needed to confirm these results.

No significant financial relationships to disclose.