POU3F3-related disorder: Defining the phenotype and expanding the molecular spectrum.

POU3F3 variants cause developmental delay, behavioral problems, hypotonia and dysmorphic features. We investigated the phenotypic and genetic landscape, and genotype-phenotype correlations in individuals with POU3F3-related disorders. We recruited unpublished individuals with POU3F3 variants through international collaborations and obtained updated clinical data on previously published individuals. Trio exome sequencing or single exome sequencing followed by segregation analysis were performed in the novel cohort. Functional effects of missense variants were investigated with 3D protein modeling. We included 28 individuals (5 previously published) from 26 families carrying POU3F3 variants; 23 de novo and one inherited from an affected parent. Median age at study inclusion was 7.4 years. All had developmental delay mainly affecting speech, behavioral difficulties, psychiatric comorbidities and dysmorphisms. Additional features included gastrointestinal comorbidities, hearing loss, ophthalmological anomalies, epilepsy, sleep disturbances and joint hypermobility. Autism, hearing and eye comorbidities, dysmorphisms were more common in individuals with truncating variants, whereas epilepsy was only associated with missense variants. In silico structural modeling predicted that all (likely) pathogenic variants destabilize the DNA-binding region of POU3F3. Our study refined the phenotypic and genetic landscape of POU3F3-related disorders, it reports the functional properties of the identified pathogenic variants, and delineates some genotype-phenotype correlations.

Rationale and design of a randomized clinical trial (Marfan Sartan) of angiotensin II receptor blocker therapy versus placebo in individuals with Marfan syndrome.

BACKGROUND: Recent studies have demonstrated that blockade of the angiotensin II type 1 receptor with losartan decreases aortic damage in an animal model of Marfan syndrome (a KI mouse model with a pathogenic mutation in the gene coding for fibrillin-1). AIMS: To demonstrate a beneficial effect of losartan on aortic dilatation when added to optimal therapy in patients with Marfan syndrome. METHODS: This is a multicentre, randomized, placebo-controlled, double-blind, clinical trial with a 2-year inclusion period and a 3-year follow-up period. Aortic root diameter will be measured using two-dimensional echocardiography. Secondary endpoints will include incidence of aortic dissection, aortic root surgery, death, quality of life, tolerance and compliance with treatments. We aim to enroll a total of 300 patients aged > or =10 years who fulfil the Ghent criteria for Marfan syndrome. Analyses will be based on intention to treat. CONCLUSION: The results of this clinical trial could lead to profound modification of the management of aortic risk and complications in patients with Marfan syndrome and possibly in patients with thoracic aortic aneurysms of other aetiologies.