Molecular testing in newborn screening: VUS burden among true positives and secondary reproductive limitations via expanded carrier screening panels.

PURPOSE: Expanded carrier screening (ECS) gene panels have several limitations, including variable content, current knowledge of disease-causing variants, and differing reporting policies. This study evaluated if the disease-associated variants identified in affected neonates who screened positive by California newborn screening (NBS) for an inherited metabolic disorder (IMD) by tandem mass spectrometry (MS/MS) would likely be reported by ECS gene panels. METHODS: Retrospective review of neonates referred by the California Department of Public Health for a positive NBS by multianalyte MS/MS from January 1, 2020 through June 30, 2021. RESULTS: One hundred thirty-six neonates screened positive for ≥1 NBS MS/MS indication. Nineteen neonates (14%) were ultimately diagnosed with an IMD, all of whom had abnormal biochemical testing. Eighteen of the 19 underwent molecular testing; 10 (56%) neonates had ≥1 variants of uncertain significance, 9 of whom were of non-White ancestry. ECS panels would have been negative for 56% (20/36) of parents with an affected neonate, 85% (17/20) of whom were of non-White ancestry. CONCLUSION: The number of variants of uncertain significance identified in this cohort highlights the need for more diversified variant databases. Due in part to the lack of diversity in currently sequenced populations, genomic sequencing cannot replace biochemical testing for the diagnosis of an IMD.

The clinical and genetic spectrum of autosomal-recessive TOR1A-related disorders.

In the field of rare diseases, progress in molecular diagnostics led to the recognition that variants linked to autosomal-dominant neurodegenerative diseases of later onset can, in the context of biallelic inheritance, cause devastating neurodevelopmental disorders and infantile or childhood-onset neurodegeneration. TOR1A-associated arthrogryposis multiplex congenita 5 (AMC5) is a rare neurodevelopmental disorder arising from biallelic variants in TOR1A, a gene that in the heterozygous state is associated with torsion dystonia-1 (DYT1 or DYT-TOR1A), an early-onset dystonia with reduced penetrance. While 15 individuals with AMC5-TOR1A have been reported (less than 10 in detail), a systematic investigation of the full disease-associated spectrum has not been conducted. Here, we assess the clinical, radiological and molecular characteristics of 57 individuals from 40 families with biallelic variants in TOR1A. Median age at last follow-up was 3 years (0-24 years). Most individuals presented with severe congenital flexion contractures (95%) and variable developmental delay (79%). Motor symptoms were reported in 79% and included lower limb spasticity and pyramidal signs, as well as gait disturbances. Facial dysmorphism was an integral part of the phenotype, with key features being a broad/full nasal tip, narrowing of the forehead and full cheeks. Analysis of disease-associated manifestations delineated a phenotypic spectrum ranging from normal cognition and mild gait disturbance to congenital arthrogryposis, global developmental delay, intellectual disability, absent speech and inability to walk. In a subset, the presentation was consistent with foetal akinesia deformation sequence with severe intrauterine abnormalities. Survival was 71%, with higher mortality in males. Death occurred at a median age of 1.2 months (1 week-9 years), due to respiratory failure, cardiac arrest or sepsis. Analysis of brain MRI studies identified non-specific neuroimaging features, including a hypoplastic corpus callosum (72%), foci of signal abnormality in the subcortical and periventricular white matter (55%), diffuse white matter volume loss (45%), mega cisterna magna (36%) and arachnoid cysts (27%). The molecular spectrum included 22 distinct variants, defining a mutational hotspot in the C-terminal domain of the Torsin-1A protein. Genotype-phenotype analysis revealed an association of missense variants in the 3-helix bundle domain to an attenuated phenotype, while missense variants near the Walker A/B motif as well as biallelic truncating variants were linked to early death. In summary, this systematic cross-sectional analysis of a large cohort of individuals with biallelic TOR1A variants across a wide age-range delineates the clinical and genetic spectrum of TOR1A-related autosomal-recessive disease and highlights potential predictors for disease severity and survival.

Rare Saposin A deficiency: Novel variant and psychosine analysis.

Saposin A is a post-translation product of the prosaposin (PSAP) gene that serves as an activator protein of the galactocerebrosidase (GALC) enzyme, and is necessary for the degradation of certain glycosphingolipids. Deficiency of saposin A leads to a clinical picture identical to that of early-infantile Krabbe disease caused by GALC enzyme deficiency. Galactosylsphingosine, also known as psychosine, is a substrate of the GALC enzyme that is known to be elevated in classic Krabbe disease. We present the case of an 18-month-old male with clinical and radiological findings concerning for Krabbe disease who had preserved GALC enzyme activity and negative GALC gene sequencing, but was found to have a homozygous variant, c.257 T > A (p.I86N), in the saposin A peptide of PSAP. Psychosine determination on dried blood spot at 18 months of age was elevated to 12 nmol/L (normal <3 nmol/L). We present this case to add to the literature on the rare diagnosis of atypical Krabbe disease due to saposin A deficiency, to report a novel presumed pathogenic variant within PSAP, and to suggest that individuals with saposin A deficiency may have elevated levels of psychosine, similar to children with classic Krabbe disease due to GALC deficiency.

Genetic counselors' attitudes toward and practice related to psychiatric genetic counseling.

Despite the high demand for psychiatric genetic counseling among people with psychiatric conditions (>90%), surveys show that genetic counselors rarely receive primary referrals for psychiatric cases. The purpose of this study was to further investigate potential barriers to the provision of psychiatric genetic counseling services, focusing specifically on the prevalence and impact of psychiatric stigmatization among genetic counselors. Board-certified, practicing genetic counselors were invited to participate in an anonymous survey via the National Society of Genetic Counselors. Survey measures included a validated psychiatric stigmatization scale (OMS-HC) and questions assaying genetic counselors' experiences with and opinions of psychiatric genetic counseling. Associations between psychiatric stigmatization and attitudes toward and practice related to psychiatric genetic counseling were computed using Pearson's correlation. The majority of respondents believed that psychiatric genetic counseling is of value to families (94%) and that it is indicated if there is a relevant personal or family history (90.3%), but only 44.6% reported providing this service. On average, respondents scored neutrally on psychiatric stigma scales; however, higher stigma levels were associated with less frequent psychiatric discussions (p = .05), less counselor comfort and perceived qualification (p = .003) and perceptions of having insufficient psychiatric genetic data (p < .02), resources (p < .02) and time (p < .03). This study suggests that the limits of psychiatric genetics research and unavailability of genetic testing lead many genetic counselors to doubt the utility of psychiatric genetic counseling. Should this mindset persist, without the intervention of psychiatric education and training, the field of genetic counseling risks continuing to inadequately serve a historically underserved population.

The importance of personalismo: Navigating obstacles in recruitment strategies for Spanish speakers in marginalized communities.

Recruitment obstacles with Spanish-speaking individuals and members of marginalized communities have been documented in the literature in narrative form, but quantitative data on effective strategies are limited. Within our research protocol assessing the impact of a storytelling intervention on knowledge and uptake of cell-free DNA (cfDNA) aneuploidy screening, three different recruitment strategies were trialed and enrollment rates were compared. Throughout the study, field notes were collected from observations in recruitment efforts. We demonstrate the effectiveness of language-concordant, personal interactions, and culturally tailored materials for recruitment of Spanish-speaking participants into genomic research studies. We also offer commentary on the experience of the researchers that provides insights to inform recruitment methods for marginalized communities.

Optic atrophy and a Leigh-like syndrome due to mutations in the c12orf65 gene: report of a novel mutation and review of the literature.

Combined oxidative phosphorylation deficiency type 7 (COXPD7) is a rare disorder of mitochondrial metabolism that results in optic atrophy and Leigh syndrome-like disease. We describe 2 siblings with compound heterozygous mutations in the recently identified C12orf65 gene who presented with optic atrophy and mild developmental delays and subsequently developed bilateral, symmetric lesions in the brainstem reminiscent of Leigh syndrome. Repeat neuroimaging demonstrated reversibility of the findings in 1 sibling and persistent metabolic stroke in the other. This article highlights the phenotypic manifestations from a novel mutation in the C12orf65 gene and reviews the clinical presentation of the 5 other individuals reported to date who carry mutations in this gene.

Implications of Provider Specialty, Test Type, and Demographic Factors on Genetic Testing Outcomes for Patients with Autism Spectrum Disorder.

A minority of patients with autism spectrum disorder (ASD) are offered genetic testing by their providers or referred for genetics evaluation despite published guidelines and consensus statements supporting genetics-informed care for this population. This study aimed to investigate the ordering habits of providers of different specialties and to additionally assess the diagnostic utility of genetic testing by test type, patient sex, and race and ethnicity. We retrospectively analyzed data associated with orders for the indication of ASD from a large clinical laboratory over 6 years (2017-2022). Geneticists and neurologists were more likely than other specialists to order exome sequencing and neurodevelopmental (NDD) panel testing while other providers were more likely to order chromosomal microarray (CMA) and Fragile X testing. Exome had the highest diagnostic yield (24.5%), followed by NDD panel (6.4%), CMA (6.2%), and Fragile X testing (0.4%). Females were 1.4x (95% CI: 1.2-1.7) more likely than males to receive a genetic diagnosis. However, for Fragile X, males had a higher diagnostic yield than females (0.4% vs 0.2%). Our findings highlight the need to enable non-genetics providers to order comprehensive genetic testing or promote referral to genetics following negative CMA and/or Fragile X testing. Our data supports that ASD testing should include exome, CMA, and other clinically indicated tests, as first-tier tests, with the consideration of panel testing, in cases where exome sequencing is not an option. Lastly, our study helps to inform expectations for genetic testing yield by test type and patient presentation.

Confirmed versus suspected: The social significance of a genetic or non-genetic diagnosis of mitochondrial disease.

This study assessed attitudes and beliefs regarding the importance of a genetic versus non-genetic diagnosis within the mitochondrial disease community. Survey respondents were categorized into two groups - those with a genetic diagnosis, and those with a non-genetic diagnosis of mitochondrial disease. We found that while both groups perceive problems with the support available to adult mitochondrial disease patients, the non-genetic group experiences less medical and social support due to lack of a definitive diagnosis. Understanding the efficacy of existing resources for mitochondrial disease sub-groups will allow for the development or improvement of resources designed to meet patient needs.

Adrenal Insufficiency in Mitochondrial Disease: A Rare Case of GFER-Related Mitochondrial Encephalomyopathy and Review of the Literature.

GFER-related mitochondrial encephalomyopathy has been previously described only in 3 siblings of a consanguineous Moroccan family. Their phenotype included congenital cataracts, hypotonia, developmental delay, and sensorineural hearing loss. Multiple mitochondrial respiratory chain complex deficiencies were identified on muscle biopsy. We describe a now-19-year-old woman with adrenal insufficiency, lactic acidosis, congenital cataracts, and respiratory insufficiency secondary to mitochondrial disorder, who was reported by North et al (1996) as a toddler. Compound heterozygous GFER mutations c.373C>T (Q125X) and c.581G>A (R194 H) were recently discovered in this patient. The purpose of this report is (1) to expand the phenotype this ultra-rare disorder and (2) to provide a review of the literature describing the unique finding of adrenal insufficiency in patients with molecularly confirmed disorders of mitochondrial metabolism.