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Background: 22q11 Deletion Syndrome (22q11DS) is the most common microdeletion syndrome with broad phenotypic variability, leading to significant morbidity and some mortality. The varied health problems associated with 22q11DS and the evolving phenotype (both medical and developmental/behavioural) across the lifespan can strongly impact the mental health of patients as well as their caregivers. Like caregivers of children with other chronic diseases, caregivers of children with 22q11DS may experience an increased risk of traumatisation and mental health symptoms.Objective: The study’s primary objective was to assess the frequency of traumatic experiences and mental health symptoms among mothers of children with 22q11DS. The secondary objective was to compare their traumatic experiences to those of mothers of children with other neurodevelopmental disorders (NDDs).Method: A total of 71 mothers of children diagnosed with 22q11DS completed an online survey about their mental health symptoms and traumatic experiences. Descriptive statistics were used to summarise the prevalence of their mental health symptoms and traumatic experiences. Logistic regression models were run to compare the traumatic experiences of mothers of children with 22q11DS to those of 335 mothers of children with other neurodevelopmental disorders (NDDs).Results: Many mothers of children with 22q11DS experienced clinically significant mental health symptoms, including depression (39%), anxiety (25%), and post-traumatic stress disorder (PTSD) symptoms (30%). The types of traumatic events experienced by mothers of children with 22q11DS differed from those of mothers of children with other NDDs as they were more likely to observe their child undergoing a medical procedure, a life-threatening surgery, or have been with their child in the intensive care unit.Conclusion: 22q11DS caregivers are likely to require mental health support and trauma-informed care, tailored to the specific needs of this population as they experience different kinds of traumatic events compared to caregivers of children with other NDDS.

Gastric cancer is among the leading causes of cancer-related deaths worldwide. While heritable forms of gastric cancer are relatively rare, identifying the genes responsible for such cases can inform diagnosis and treatment for both hereditary and sporadic cases of gastric cancer. Mutations in the E-cadherin gene, CDH1, account for 40% of the most common form of familial gastric cancer (FGC), hereditary diffuse gastric cancer (HDGC). The genes responsible for the remaining forms of FGC are currently unknown. Here we examined a large family from Maritime Canada with FGC without CDH1 mutations, and identified a germline coding variant (p.P946L) in mitogen-activated protein kinase kinase kinase 6 (MAP3K6). Based on conservation, predicted pathogenicity and a known role of the gene in cancer predisposition, MAP3K6 was considered a strong candidate and was investigated further. Screening of an additional 115 unrelated individuals with non-CDH1 FGC identified the p.P946L MAP3K6 variant, as well as four additional coding variants in MAP3K6 (p.F849Sfs*142, p.P958T, p.D200Y and p.V207G). A somatic second-hit variant (p.H506Y) was present in DNA obtained from one of the tumor specimens, and evidence of DNA hypermethylation within the MAP3K6 gene was observed in DNA from the tumor of another affected individual. These findings, together with previous evidence from mouse models that MAP3K6 acts as a tumor suppressor, and studies showing the presence of somatic mutations in MAP3K6 in non-hereditary gastric cancers and gastric cancer cell lines, point towards MAP3K6 variants as a predisposing factor for FGC.

Charcot-Marie-Tooth disease (CMT) represents a family of related sensorimotor neuropathies. We studied a large family from a rural eastern Canadian community, with multiple individuals suffering from a condition clinically most similar to autosomal recessive axonal CMT, or AR-CMT2. Homozygosity mapping with high-density SNP genotyping of six affected individuals from the family excluded 23 known genes for various subtypes of CMT and instead identified a single homozygous region on chromosome 9, at 122,423,730-129,841,977 Mbp, shared identical by state in all six affected individuals. A homozygous pathogenic variant was identified in the gene encoding leucine rich repeat and sterile alpha motif 1 (LRSAM1) by direct DNA sequencing of genes within the region in affected DNA samples. The single nucleotide change mutates an intronic consensus acceptor splicing site from AG to AA. Direct analysis of RNA from patient blood demonstrated aberrant splicing of the affected exon, causing an obligatory frameshift and premature truncation of the protein. Western blotting of immortalized cells from a homozygous patient showed complete absence of detectable protein, consistent with the splice site defect. LRSAM1 plays a role in membrane vesicle fusion during viral maturation and for proper adhesion of neuronal cells in culture. Other ubiquitin ligases play documented roles in neurodegenerative diseases. LRSAM1 is a strong candidate for the causal gene for the genetic disorder in our kindred.