The Canadian genetic counseling workforce: Perspectives from employers and recent graduates.

There is a lack of literature devoted to the Canadian genetic counseling workforce. Current and prospective genetic counseling students, graduates, employers, programs, and funding agencies remain largely uninformed of trends in the job market. The purpose of this study was to investigate the employment experiences of recent Canadian genetic counseling graduates and employers of genetic counselors (GCs) in Canada. An online survey was distributed to Canadians who had graduated from North American genetic counseling programs from 2014 to 2018 and to employers with experience hiring patient-facing genetic counselors from 2016 to 2018. Quantitative data were analyzed through descriptive statistics and, where appropriate, logistic regression. Qualitative data were reviewed to illustrate and support the quantitative data. Half of the employer responders (11/22) reported hiring more or many more genetic counselors compared to 3 years ago (2016), and a majority (n = 19, 86%) reported a desire to hire at least one more genetic counselor if funding were available. Most graduates (45/70, 64%) reported securing employment before graduation, 33% (n = 23) within 6 months of graduation, and no one taking longer than 1 year. For recent graduates, location was the most important factor when looking for work, and those who chose to work in Canada experienced significantly more challenges gaining employment as opposed to those who worked internationally (p = 0.03). The specialties in highest demand for genetic counselors and the most common areas of practice for recent graduates included adult general genetics, prenatal genetics, and cancer genetics. Overall, our findings suggest that there is a growth of employment opportunities in Canada and more employer-reported need for clinical genetic counselors; however, there is a lack of funding to support this expansion.

Partial Loss of USP9X Function Leads to a Male Neurodevelopmental and Behavioral Disorder Converging on Transforming Growth Factor ß Signaling.

BACKGROUND: The X-chromosome gene USP9X encodes a deubiquitylating enzyme that has been associated with neurodevelopmental disorders primarily in female subjects. USP9X escapes X inactivation, and in female subjects de novo heterozygous copy number loss or truncating mutations cause haploinsufficiency culminating in a recognizable syndrome with intellectual disability and signature brain and congenital abnormalities. In contrast, the involvement of USP9X in male neurodevelopmental disorders remains tentative. METHODS: We used clinically recommended guidelines to collect and interrogate the pathogenicity of 44 USP9X variants associated with neurodevelopmental disorders in males. Functional studies in patient-derived cell lines and mice were used to determine mechanisms of pathology. RESULTS: Twelve missense variants showed strong evidence of pathogenicity. We define a characteristic phenotype of the central nervous system (white matter disturbances, thin corpus callosum, and widened ventricles); global delay with significant alteration of speech, language, and behavior; hypotonia; joint hypermobility; visual system defects; and other common congenital and dysmorphic features. Comparison of in silico and phenotypical features align additional variants of unknown significance with likely pathogenicity. In support of partial loss-of-function mechanisms, using patient-derived cell lines, we show loss of only specific USP9X substrates that regulate neurodevelopmental signaling pathways and a united defect in transforming growth factor ß signaling. In addition, we find correlates of the male phenotype in Usp9x brain-specific knockout mice, and further resolve loss of hippocampal-dependent learning and memory. CONCLUSIONS: Our data demonstrate the involvement of USP9X variants in a distinctive neurodevelopmental and behavioral syndrome in male subjects and identify plausible mechanisms of pathogenesis centered on disrupted transforming growth factor ß signaling and hippocampal function.

Mutations in ILK, encoding integrin-linked kinase, are associated with arrhythmogenic cardiomyopathy.

Arrhythmogenic cardiomyopathy is a genetic heart muscle disorder characterized by fibro-fatty replacement of cardiomyocytes leading to life-threatening ventricular arrhythmias, heart failure, and sudden cardiac death. Mutations in genes encoding cardiac junctional proteins are known to cause about half of cases, while remaining genetic causes are unknown. Using exome sequencing, we identified 2 missense variants (p.H33N and p.H77Y) that were predicted to be damaging in the integrin-linked kinase (ILK) gene in 2 unrelated families. The p.H33N variant was found to be de novo. ILK links integrins and the actin cytoskeleton, and is essential for the maintenance of normal cardiac function. Both of the new variants are located in the ILK ankyrin repeat domain, which binds to the first LIM domain of the adaptor proteins PINCH1 and PINCH2. In silico binding studies proposed that the human variants disrupt the ILK-PINCH complex. Recombinant mutant ILK expressed in H9c2 rat myoblast cells shows aberrant prominent cytoplasmic localization compared to the wild-type. Expression of human wild-type and mutant ILK under the control of the cardiac-specific cmlc2 promotor in zebrafish shows that p.H77Y and p.P70L, a variant previously reported in a dilated cardiomyopathy family, cause cardiac dysfunction and death by about 2-3 weeks of age. Our findings provide genetic and functional evidence that ILK is a cardiomyopathy disease gene and highlight its relevance for diagnosis and genetic counseling of inherited cardiomyopathies.

Fetal Outcomes of Prenatally Diagnosed Congenital Diaphragmatic Hernia: Nine Years of Clinical Experience in a Canadian Tertiary Hospital.

OBJECTIVE: To summarize the clinical outcome of congenital diaphragmatic hernia (CDH) identified on prenatal ultrasound. METHOD: We reviewed prenatally detected cases of CDH diagnosed between July 2000 and September 2009 at a single tertiary-care facility. RESULTS: Ninety-one cases were identified. Sixty-nine cases had complete medical records including karyotype. Of these, 40 were isolated defects and 29 cases had additional congenital or chromosome anomalies. An abnormal karyotype was present in 17.4% overall, affecting 2.5% of cases of isolated CDH (1/40) and 37.9% of cases of non-isolated CDH (11/29). The rate of termination of pregnancy in cases of isolated CDH diagnosed prior to 24 weeks was 33.3% (10/30), and in cases of non-isolated CDH it was 73.9% (17/23). The survival rate of the 44 liveborn infants was 66.7% (24/36) for those with isolated CDH and 37.5% (3/8) for those with non-isolated CDH. The decision to terminate the pregnancy was made in 73.9% of fetuses with prenatally diagnosed karyotype or additional anatomical abnormalities, in contrast to 37.5% of prenatally diagnosed isolated CDH. CONCLUSION: The outcomes of pregnancies that continue after identification of CDH are in keeping with previous reports, with an overall survival rate of 61.4%. The presence of additional anatomical anomalies was the only predictor of mortality among liveborn infants.

The genotypic and phenotypic spectrum of PIGA deficiency.

BACKGROUND: Phosphatidylinositol glycan biosynthesis class A protein (PIGA) is one of the enzymes involved in the biosynthesis of glycosylphosphatidylinositol (GPI) anchor proteins, which function as enzymes, adhesion molecules, complement regulators and co-receptors in signal transduction pathways. Until recently, only somatic PIGA mutations had been reported in patients with paroxysmal nocturnal hemoglobinuria (PNH), while germline mutations had not been observed, and were suspected to result in lethality. However, in just two years, whole exome sequencing (WES) analyses have identified germline PIGA mutations in male patients with XLIDD (X-linked intellectual developmental disorder) with a wide spectrum of clinical presentations. METHODS AND RESULTS: Here, we report on a new missense PIGA germline mutation [g.15342986C>T (p.S330N)] identified via WES followed by Sanger sequencing, in a Chinese male infant presenting with developmental arrest, infantile spasms, a pattern of lesion distribution on brain MRI resembling that typical of maple syrup urine disease, contractures, dysmorphism, elevated alkaline phosphatase, mixed hearing loss (a combination of conductive and sensorineural), liver dysfunction, mitochondrial complex I and V deficiency, and therapy-responsive dyslipidemia with confirmed lipoprotein lipase deficiency. X-inactivation studies showed skewing in the clinically unaffected carrier mother, and CD109 surface expression in patient fibroblasts was 57% of that measured in controls; together these data support pathogenicity of this mutation. Furthermore, we review all reported germline PIGA mutations (1 nonsense, 1 frameshift, 1 in-frame deletion, five missense) in 8 unrelated families. CONCLUSIONS: Our case further delineates the heterogeneous phenotype of this condition for which we propose the term 'PIGA deficiency'. While the phenotypic spectrum is wide, it could be classified into two types (severe and less severe) with shared hallmarks of infantile spasms with hypsarrhythmia on EEG and profound XLIDD. In severe PIGA deficiency, as described in our patient, patients also present with dysmorphic facial features, multiple CNS abnormalities, such as thin corpus callosum and delayed myelination, as well as hypotonia and elevated alkaline phosphatase along with liver, renal, and cardiac involvement; its course is often fatal. The less severe form of PIGA deficiency does not involve facial dysmorphism and multiple CNS abnormalities; instead, patients present with milder IDD, treatable seizures and generally a longer lifespan.

Characterization of a new X-linked mental retardation syndrome with microcephaly, cortical malformation, and thin habitus.

X-linked mental retardation (XLMR) affects 1-2/1,000 males and accounts for approximately 10% of all mental retardation (MR). We have ascertained a syndromic form of XLMR segregating within a five-generation family with seven affected males. Prominent characteristics include mild to severe MR, cortical malformation, microcephaly, seizures, thin build with distinct facial features including a long and thin face, epicanthic folds, almond-shaped eyes, upslanting palpebral fissures and micrognathia and behavioral problems. Carrier females have normal physical appearance and intelligence. This combination of features is unreported and distinct from Lujan-Fryns syndrome, Snyder-Robinson syndrome, and zinc finger DHHC domain-containing 9-associated MR. We propose the name of this new syndrome to be CK syndrome.

Consideration of genetic counseling as a career: implications for diversifying the genetic counseling field.

Under-representation of racial/ethnic minority counselors has been an ongoing issue in the genetic counseling field. A better understanding of genetic counseling awareness and career consideration may help to increase the number of applicants to genetic counseling training programs from racial/ethnic minorities. This study sampled high school and college students (n = 233) to examine their awareness and perceptions of genetic counseling. Ethnicity, gender, parental level of education, and interest in biology were significant predictors of a subject's genetic counseling awareness; previous awareness of genetic counseling, interest in psychology, and level of education were significant predictors of whether a subject would consider genetic counseling as a career. The findings suggest that knowledge of genetic counseling is lower among racial/ethnic minorities, but that racial/ethnic minorities are just as likely to consider genetic counseling as a career. Awareness of genetic counseling prior to university education may increase racial/ethnic minority representation among potential applicants to genetic counseling training programs.

Outcome of prenatally diagnosed trisomy 6 mosaicism.

We report the prenatal diagnosis of trisomy 6 mosaicism via amniocentesis, in which trisomy 6 cells were identified in three of five culture vessels with 33% (5/15) of colonies showing trisomic cells. The pregnancy was electively terminated and examination revealed minor abnormalities (shortening of the femurs, micrognathia, posterior malrotation of the ears, and bilateral camptomelia of the second digit of the hands and fifth digits of the feet). Cytogenetic analysis of the placenta showed trisomy 6 in 100% of 20 cells studied. Karyotype was 46,XX in 100 cells examined from fetal skin. There are relatively few prenatally diagnosed cases of mosaic trisomy 6 at amniocentesis. Confined placental mosaicism (CPM) has been postulated in other cases where follow-up cytogenetic studies were not available. The present case differs from those previously reported, as it appears to represent CPM of chromosome 6 with phenotypic effects to the fetus.