A New Pathologic KMT2B Variant Associated with Childhood Onset Dystonia Presenting as Variable Phenotypes among Family Members.

Background: KMT2B-related dystonia is a primarily childhood-onset movement disorder characterized by progressive dystonia, spasticity, and developmental delay. A minority of individuals possess an inherited KMT2B variant. Case Report: As a child, the proband experienced mild developmental delay and laryngeal dystonia which progressed to generalized dystonia. Patellar hyperreflexia, postural tremor, and everted gait were documented. Whole exome sequencing identified a heterozygous pathogenic KMT2B variant in the proband, proband's sister, and proband's mother who had milder presentations. Discussion: This novel KMT2B variant reflects intrafamilial variable expressivity in KMT2B-related dystonia. Further identification of variants will allow for better appreciation of the phenotypic spectrum.

Exploring United States genetic counselor and healthcare interpreter perspectives: Allocation of roles within the genetic counseling encounter.

Genetic counselors (GCs) and healthcare interpreters (HIs) are key members of the healthcare team when providing genetic counseling services to patients with Limited English Proficiency (LEP); however, the working relationship between GCs and HIs and the role each member plays within a genetic counseling session is unclear. Previous studies assessing this relationship have been qualitative and limited in sample size (Agather et al., 2018, Journal of Genetic Counseling, 26, 1388; Krieger et al., 2018, Journal of Genetic Counseling, 26, 1388; Lara-Otero et al., 2019, Health Communication, 34, 1608; Rosenbaum et al., 2020, Journal of Genetic Counseling, 29, 352). This study utilized a quantitative approach to allow for sampling of larger populations and to simultaneously understand current perspectives of GCs and HIs regarding each other's and their own roles within a genetic counseling session. GC and HI participants from the United States were recruited via email to complete an online survey with questions regarding interactions prior to a session, roles during a session, and opportunities for collaboration and constraints in the working relationship. Descriptive and inferential statistics were utilized to analyze responses of GCs and HIs. 130 GC and 40 HI participants were included in this study. There were statistically significant differences (p < .001) in responses between GC and HI participants on the expected distribution of roles during a session in advocacy, psychosocial and cultural domains. Additionally, this study identified that HI desired resources and training regarding genetics and genetic counseling are currently not being met. To our knowledge, this is the largest study to simultaneously survey GC and HI perspectives on these topics. Our findings suggest the need for greater communication and collaboration between GCs and HIs to ensure high-quality care for patients with LEP. Integrating a pre-session meeting between the GC and HI for sessions with patients with LEP and increasing education for GCs and HIs on the roles each group brings into a session is warranted to optimize this collaborative relationship and patient care.

Evaluation and classification of severity for 176 genes on an expanded carrier screening panel.

BACKGROUND: Disease severity is important when considering genes for inclusion on reproductive expanded carrier screening (ECS) panels. We applied a validated and previously published algorithm that classifies diseases into four severity categories (mild, moderate, severe, and profound) to 176 genes screened by ECS. Disease traits defining severity categories in the algorithm were then mapped to four severity-related ECS panel design criteria cited by the American College of Obstetricians and Gynecologists (ACOG). METHODS: Eight genetic counselors (GCs) and four medical geneticists (MDs) applied the severity algorithm to subsets of 176 genes. MDs and GCs then determined by group consensus how each of these disease traits mapped to ACOG severity criteria, enabling determination of the number of ACOG severity criteria met by each gene. RESULTS: Upon consensus GC and MD application of the severity algorithm, 68 (39%) genes were classified as profound, 71 (40%) as severe, 36 (20%) as moderate, and one (1%) as mild. After mapping of disease traits to ACOG severity criteria, 170 out of 176 genes (96.6%) were found to meet at least one of the four criteria, 129 genes (73.3%) met at least two, 73 genes (41.5%) met at least three, and 17 genes (9.7%) met all four. CONCLUSION: This study classified the severity of a large set of Mendelian genes by collaborative clinical expert application of a trait-based algorithm. Further, it operationalized difficult to interpret ACOG severity criteria via mapping of disease traits, thereby promoting consistency of ACOG criteria interpretation.

De Novo Frameshift Variants in the Neuronal Splicing Factor NOVA2 Result in a Common C-Terminal Extension and Cause a Severe Form of Neurodevelopmental Disorder.

The neuro-oncological ventral antigen 2 (NOVA2) protein is a major factor regulating neuron-specific alternative splicing (AS), previously associated with an acquired neurologic condition, the paraneoplastic opsoclonus-myoclonus ataxia (POMA). We report here six individuals with de novo frameshift variants in NOVA2 affected with a severe neurodevelopmental disorder characterized by intellectual disability (ID), motor and speech delay, autistic features, hypotonia, feeding difficulties, spasticity or ataxic gait, and abnormal brain MRI. The six variants lead to the same reading frame, adding a common proline rich C-terminal part instead of the last KH RNA binding domain. We detected 41 genes differentially spliced after NOVA2 downregulation in human neural cells. The NOVA2 variant protein shows decreased ability to bind target RNA sequences and to regulate target AS events. It also fails to complement the effect on neurite outgrowth induced by NOVA2 downregulation in vitro and to rescue alterations of retinotectal axonal pathfinding induced by loss of NOVA2 ortholog in zebrafish. Our results suggest a partial loss-of-function mechanism rather than a full heterozygous loss-of-function, although a specific contribution of the novel C-terminal extension cannot be excluded.

Interpreters' perceptions of culture bumps in genetic counseling.

Culture bump theory provides a practical and goal-oriented framework for addressing cultural differences that can impact communication and patient care. Differences in language and culture, coupled with a lack of knowledge or competency regarding these differences, often contribute to 'culture bumps' between healthcare providers and patients. Interpreters serve the unique role of 'cultural brokers', going beyond bridging the linguistic divide to close cultural gaps. Research from the perspective of interpreters focused on culture bumps and cultural competency within genetic counseling sessions is lacking. We aimed to assess interpreters' experiences with significant 'culture bumps' in genetic counseling sessions, obtain interpreters' perspectives regarding genetic counselors' gaps in cultural competency, and explore interpreters' perceptions of the impact of cultural competency on the genetic counseling sessions. Spanish and Polish interpreters experienced in working in person with genetic counselors were recruited through interpreter supervisors at medical centers, hospitals, and interpreter training and service agencies in the Chicagoland area. Using a semi-structured interview guide, phone interviews were conducted with eligible participants and transcribed verbatim. A codebook was developed between two coders, and inter-rater reliability was assessed (κ = 0.82). Grounded theory was used as a guiding principle to code data. The results of this study revealed significant culture bumps identified by interpreters in genetic counseling sessions in the areas of exchange of information, gender and family dynamics, and incorporation of religious and faith beliefs. Interpreters identified the impact on rapport, both negative and positive, due to gaps and strengths in cultural competency, respectively. These responses offer useful insight for training and providing practicing genetic counselors with tools to promote cultural competency, in order to provide optimal care for patients with limited English proficiency (LEP). Further research is necessary to explore these concepts within other languages and cultures, as well as to determine the most appropriate methods for implementing these suggestions for improvement.

Behavioral abnormalities are common and severe in patients with distal 22q11.2 microdeletions and microduplications.

We describe six individuals with microdeletions and microduplications in the distal 22q11.2 region detected by microarray. Five of the abnormalities have breakpoints in the low-copy repeats (LCR) in this region and one patient has an atypical rearrangement. Two of the six patients with abnormalities in the region between LCR22 D-E have hearing loss, which has previously been reported only once in association with these abnormalities. We especially note the behavioral/neuropsychiatric problems, including the severity and early onset, in patients with distal 22q11.2 rearrangements. Our patients add to the genotype-phenotype correlations which are still being generated for these chromosomal anomalies.

Genetics professionals' opinions of whole-genome sequencing in the newborn period.

Newborn screening (NBS) programs have been successful in identifying infants with rare, treatable, congenital conditions. While current programs rely largely on biochemical analysis, some predict that in the future, genome sequencing may be used as an adjunct. The purpose of this exploratory pilot study was to begin to characterize genetics professionals' opinions of the use of whole-genome sequencing (WGS) in NBS. We surveyed members of the American College of Medical Genetics and Genomics (ACMG) via an electronic survey distributed through email. The survey included questions about results disclosure, the current NBS paradigm, and the current criteria for adding a condition to the screening panel. The response rate was 7.3 % (n = 113/1549). The majority of respondents (85 %, n = 96/113) felt that WGS should not be currently used in NBS, and that if it were used, it should not be mandatory (86.5 %, n = 96/111). However, 75.7 % (n = 84/111) foresee it as a future use of WGS. Respondents felt that accurate interpretation of results (86.5 %, n = 83/96), a more extensive consent process (72.6 %, n = 69/95), pre- (79.2 %, n = 76/96) and post-test (91.6 %, n = 87/95) counseling, and comparable costs (70.8 %, n = 68/96) and turn-around-times (64.6 %, n = 62/96) to current NBS would be important for using WGS in NBS. Participants were in favor of disclosing most types of results at some point in the lifetime. However, the majority (87.3 %, n = 96/110) also indicated that parents should be able to choose what results are disclosed. Overall, respondents foresee NBS as a future use of WGS, but indicated that WGS should not occur within the framework of traditional NBS. They agreed with the current criteria for including a condition on the recommended uniform screening panel (RUSP). Further discussion about these criteria is needed in order to better understand how they could be utilized if WGS is incorporated into NBS.

Two novel compound heterozygous mutations in OPA3 in two siblings with OPA3-related 3-methylglutaconic aciduria.

OPA3-related 3-methylglutaconic aciduria, or Costeff Optic Atrophy syndrome, is a neuro-ophthalmologic syndrome of early-onset bilateral optic atrophy and later-onset spasticity, and extrapyramidal dysfunction. Urinary excretion of 3-methylglutaconic acid and of 3-methylglutaric acid is markedly increased. OPA3-related 3-methylglutaconic aciduria is due to mutations in the OPA3 gene located at 19q13.2-13.3. Here we describe two siblings with novel compound heterozygous variants in OPA3: c.1A>G (p.1M>V) in the translation initiation codon in exon 1 and a second variant, c.142+5G>C in intron 1. On cDNA sequencing the c.1A>G appeared homozygous, indicating that the allele without the c.1A>G variant is degraded. This is likely due to an intronic variant; possibly the IVS1+5 splice site variant. The older female sibling initially presented with motor developmental delay and vertical nystagmus during her first year of life and was diagnosed subsequently with optic atrophy. Her brother presented with mildly increased hip muscle tone followed by vertical nystagmus within the first 6 months of life, and was found to have elevated urinary excretion of 3-methylglutaconic acid and 3-methylglutaric acid, and optic atrophy by 1.5 years of age. Currently, ages 16 and 7, both children exhibit ataxic gaits and dysarthric speech. Immunofluorescence studies on patient's cells showed fragmented mitochondrial morphology. Thus, though the exact function of OPA3 remains unknown, our experimental results and clinical summary provide evidence for the pathogenicity of the identified OPA3 variants and provide further evidence for a mitochondrial pathology in this disease.

Mutations in PPIB (cyclophilin B) delay type I procollagen chain association and result in perinatal lethal to moderate osteogenesis imperfecta phenotypes.

Recessive mutations in the cartilage-associated protein (CRTAP), leucine proline-enriched proteoglycan 1 (LEPRE1) and peptidyl prolyl cis-trans isomerase B (PPIB) genes result in phenotypes that range from lethal in the perinatal period to severe deforming osteogenesis imperfecta (OI). These genes encode CRTAP (encoded by CRTAP), prolyl 3-hydroxylase 1 (P3H1; encoded by LEPRE1) and cyclophilin B (CYPB; encoded by PPIB), which reside in the rough endoplasmic reticulum (RER) and can form a complex involved in prolyl 3-hydroxylation in type I procollagen. CYPB, a prolyl cis-trans isomerase, has been thought to drive the prolyl-containing peptide bonds to the trans configuration needed for triple helix formation. Here, we describe mutations in PPIB identified in cells from three individuals with OI. Cultured dermal fibroblasts from the most severely affected infant make some overmodified type I procollagen molecules. Proα1(I) chains are slow to assemble into trimers, and abnormal procollagen molecules concentrate in the RER, and bind to protein disulfide isomerase (PDI) and prolyl 4-hydroxylase 1 (P4H1). These findings suggest that although CYPB plays a role in helix formation another effect is on folding of the C-terminal propeptide and trimer formation. The extent of procollagen accumulation and PDI/P4H1 binding differs among cells with mutations in PPIB, CRTAP and LEPRE1 with the greatest amount in PPIB-deficient cells and the least in LEPRE1-deficient cells. These findings suggest that prolyl cis-trans isomerase may be required to effectively fold the proline-rich regions of the C-terminal propeptide to allow proα chain association and suggest an order of action for CRTAP, P3H1 and CYPB in procollagen biosynthesis and pathogenesis of OI.