A 132 bp deletion affecting the KCNQ1OT1 gene associated with Silver-Russell syndrome clinical phenotype.

BACKGROUND: Imprinting centre 2 (IC2) in the chromosomal region 11p15.5 regulates the monoallelic expression of imprinted genes by differential methylation of paternal and maternal chromosomes. Copy number variants in IC2 are associated with Beckwith-Wiedemann syndrome and Silver-Russell syndrome (SRS). Clinical outcome of IC2 deletions seems to depend on the parental origin of the chromosome, deletion size and inclusion or exclusion of enhancer and promoter regions. RESULTS: A paternally inherited 132 bp deletion within the KCNQ1OT1 gene was found in a proband with an SRS clinical phenotype. The patient's father and paternal grandmother, who both carry the deletion on their maternal chromosome, are unaffected. Review of other IC2 deletions and their associated clinical presentation was useful in understanding the genetic-phenotypic correlation. CONCLUSION: Only six cases have been reported with deletions involving exclusively IC2, one being identical to our proband's 132 bp deletion. Our study, which is based on more extensive segregation data than the previous 132 bp deletion report, confirms the association of this deletion with growth restriction when paternally inherited. Remarkably, even though our patient has the same deletion, he has more pronounced phenotypic features; our findings thus suggest that some degree of clinical variability may be associated with this loss.

A novel CHD3 variant in a patient with central precocious puberty: Expanded phenotype of Snijders Blok-Campeau syndrome?

Snijders Blok-Campeau syndrome is an autosomal dominant genetic disorder first described in 2018, mostly associated with de novo variants in the CHD3 gene that affects chromatin remodeling. This syndrome is characterized by developmental delay, speech delay, and intellectual disability, but only about 60 affected individuals have been reported to date. We report a de novo likely pathogenic CHD3 variant (c.5609G > A; p. (Arg1870Gln)) in a young female presenting with features of Snijders Blok-Campeau syndrome including speech delay, autism spectrum disorder, learning difficulties, characteristic facial dysmorphisms, and a feature not previously described in this syndrome, idiopathic central precocious puberty. Her puberty was controlled with monthly injections of a GnRH analogue. Targeted exome sequencing was negative for genes known to be responsible for central precocious puberty. Our case raises the possibility that variants in CHD3 gene may also result in central precocious puberty. Strengthening this association could expand the phenotypic spectrum of the Snijders Blok-Campeau syndrome and should be included in multigene panels for precocious puberty.

Phenotypic spectrum associated with pathogenic mutation in the NRG1 gene in Acadian family.

NRG1 is a gene that encodes for a protein that binds to a receptor of the tyrosine kinase family which is essential for the survival of the central nervous system development during embryogenesis. Mutation of the NRG1 gene causes aganglionosis, which leads to Hirschsprung disease. Two brothers of Acadian descent presented with a history of Hirschsprung disease, in association with other anomalies including congenital heart disease, learning difficulties, developmental issues, and hypopigmented hair patch. Molecular analysis in both siblings revealed a heterozygous pathogenic mutation in the NGR1 gene (c.235C>T [p.Arg79*]), that was inherited from an unaffected father. This family expands our knowledge about the phenotypic spectrum associated with pathogenic mutation in the NRG1 gene with intrafamilial variability and the likely reduced penetrance for the phenotypic expression.

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly is caused by a duplication in RUNX2.

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly (MDMHB) is an autosomal-dominant bone dysplasia characterized by metaphyseal flaring of long bones, enlargement of the medial halves of the clavicles, maxillary hypoplasia, variable brachydactyly, and dystrophic teeth. We performed genome-wide SNP genotyping in five affected and four unaffected members of an extended family with MDMHB. Analysis for copy-number variations revealed that a 105 kb duplication within RUNX2 segregated with the MDMHB phenotype in a region with maximum linkage. Real-time PCR for copy-number variation in genomic DNA in eight samples, as well as sequence analysis of fibroblast cDNA from one subject with MDMHB confirmed that affected family members were heterozygous for the presence of an intragenic duplication encompassing exons 3 to 5 of RUNX2. These three exons code for the Q/A domain and the functionally essential DNA-binding runt domain of RUNX2. Transfection studies with murine Runx2 cDNA showed that cellular levels of mutated RUNX2 were markedly higher than those of wild-type RUNX2, suggesting that the RUNX2 duplication found in individuals with MDMHB leads to a gain of function. Until now, only loss-of-function mutations have been detected in RUNX2; the present report associates an apparent gain-of-function alteration of RUNX2 function with a distinct rare disease.

Osteogenesis imperfecta.

Osteogenesis imperfecta (OI), an inherited skeletal disorder characterized by low bone mass, bone fragility, and often short stature. The clinical severity varies widely from being nearly asymptomatic with a mild predisposition to fractures, normal stature and normal lifespan being to profoundly disabling and even lethal. Extra skeletal manifestations may include blue-grey sclera and dental abnormalities. Initially, the classification of OI into four types was based on clinical findings, but more recently additional types OI (types V-XI) have been ascertained, based on the identification of different mutations. While this classification is somewhat controversial, it is described in this article. The treatment of patients with OI is based on the nature and severity of symptoms. The goal of therapy is to prevent fractures and disability, improve function and quality of life. A multidisciplinary approach is needed, and treatment options include medication such as bisphosphonates, surgery, and rehabilitation. Investigations continue to explore gene and cell therapies that may be developed in the future.

Dividend policy and crisis: Exploring the interplay between performance and financial constraints in the French context.

The purpose of this paper is to determine the effect of the Covid-19 pandemic crisis on dividend policy and performance and explore the interplay between performance and financial constraints to identify how such a fit affected dividend policy during the crisis. We used a final sample of 106 SBF-listed firms during six years. To assess the effect of the crisis, we divided this period into three subperiods: pre-crisis (2016-2018), pandemic period (2019-2021), and all periods (2016-2021). A System Generalized Method of Moments (SGMM) is used to deal with the problem of endogeneity caused by the lagged dependent variable. The results showed that only the crisis and the financial constraints (KZ index) negatively correlated with dividend payment levels (DivPaid). This dividend level did not take performance into account. Regarding the control variables, only debt, growth, and size positively impacted dividend levels. Moreover, the performance of French companies was negatively influenced by the DividPaid, KZindex, and Crisis variables. The findings suggest that France should prioritize dividend payments to protect a company's reputation and financial health. These findings have significant implications for investors, financial analysts, regulators, and policymakers who are looking for guidance on dividend policy in uncertain situations.

Novel dermatological and skeletal features associated with PTEN variant in PTEN hamartoma tumor syndrome.

PTEN hamartoma tumor syndromes (PHTS) comprise hamartomatous overgrowth syndromes associated with PTEN germline mutations. In this case report, we describe a variant identified by next generation sequencing causing peculiar dermatological and skeletal features not yet described in the literature. Being cognizant of such unique disease presentations in PHTS, that manifest at a very young age, could help facilitate a timely diagnosis by clinicians and thus the early education of families on active cancer surveillance. This specific case also strengthens the concept of variable presentation of PHTS and the need for genetic testing early on, even if not all criteria for PHTS are met for a formal clinical diagnosis.

Pathogenic variants carrier screening in New Brunswick: Acadians reveal high carrier frequency for multiple genetic disorders.

BACKGROUND: Founder populations that have recently undergone important genetic bottlenecks such as French-Canadians and Ashkenazi Jews can harbor some pathogenic variants at a higher carrier rate than the general population, putting them at a higher risk for certain genetic diseases. In these populations, there can be considerable benefit to performing ethnic-based or expanded preconception carrier screening, which can help in the prevention or early diagnosis and management of some genetic diseases. Acadians are descendants of French immigrants who settled in the Atlantic Coast of Canada in the seventeenth century. Yet, the Acadian population has never been investigated for the prevalence/frequency of disease-causing genetic variants. METHODS: An exome sequencing panel for 312 autosomal recessive and 30 X-linked diseases was designed and specimens from 60 healthy participants were sequenced to assess carrier frequency for the targeted diseases. RESULTS: In this study, we show that a sample population of Acadians in South-East New Brunswick harbor variants for 28 autosomal recessive and 1 X-linked diseases, some of which are significantly more frequent in comparison to reference populations. CONCLUSION: Results from this pilot study suggests a need for further investigation of genomic variation in this population and possibly implementation of targeted carrier and neonatal screening programs.

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly in a Finnish woman: first confirmation of a duplication in RUNX2 as pathogenic variant.

Metaphyseal dysplasia with maxillary hypoplasia and brachydactyly (MDMHB) is an autosomal-dominant bone dysplasia that until now has only been reported in French Canadian individuals. We have recently identified an intragenic duplication in RUNX2, encompassing exons 3 to 5, as a cause of MDMHB in French Canadian families. Here we describe a 20-year-old Finnish woman who had typical clinical and radiological signs of MDMHB, the first reported individual with MDMHB who is not of French-Canadian origin. Copy number variant assays based on quantitative PCR of genomic DNA showed the presence of three copies within a part of RUNX2. Sequencing RUNX2 cDNA from the skin fibroblasts revealed a duplication of exons 3 to 5. The results demonstrated that the intronic breakpoints of the duplication differed from those previously found in the French Canadian family, but that the consequences on RUNX2 transcript were identical. These findings demonstrate that the MDMHB phenotype results from an intragenic duplication of RUNX2 exons 3 to 5 also outside of the community where the disorder was first identified.

Abnormalities in muscle density and muscle function in hypophosphatemic rickets.

CONTEXT: Animal studies suggest that hypophosphatemic rickets (HPR) is associated with muscle function deficits, but it is unknown whether humans with HPR have a muscle disorder. OBJECTIVE: Our objective was to assess calf muscle size and density (an indicator of muscle quality) and lower extremity muscle function in patients with HPR. SETTING: The study was carried out in the outpatient department of a pediatric orthopedic hospital. PATIENTS AND OTHER PARTICIPANTS: Participants included 34 individuals with HPR (6-60 yr; nine males) and 34 age- and gender-matched controls. MAIN OUTCOME MEASURES: Calf muscle parameters (muscle cross-sectional area and density) were measured by peripheral quantitative computed tomography. Lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by jumping mechanography through five tests with different levels of difficulty: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test. RESULTS: Compared with age- and gender-matched controls, patients with HPR had normal muscle size (P = 0.58) but lower muscle density (P = 0.008) and lower peak muscle force and power (P < 0.001 in each test). Muscle function tests were also lower in the subgroup of patients with straight legs (n = 13) than in controls, even though patients with straight legs had higher muscle function test results than patients with severe leg deformities. CONCLUSIONS: The present study suggests that muscle weakness is a clinical feature of HPR. Lower muscle quality and limb deformities contribute to this functional deficit.