Leveling the field: Development of an asynchronous interactive module series for genetic counseling trainees on molecular testing and variant interpretation.

The need for education focusing on genomic technologies and variant interpretation for genetic counseling trainees has prompted genetic counseling training programs to alter their curricula to incorporate this content. Given students' diverse experiences prior to matriculation into genetic counseling training programs, students' familiarity with these topics may vary. Following receipt of feedback from trainees at a large genetic counseling program regarding an existing course focused on molecular technologies, a three-part asynchronous module series was created as a prerequisite to this course as an opportunity to align knowledge. Designed to be completed by students on their own time and at their own pace, the modules allowed for additional instruction without increases in classroom time or credit hours. Content included a refresh on genetics concepts and an introduction to available genetics resources for developing a differential diagnosis as well as variant interpretation framework. Modules utilized a clinical scenario to anchor learning with interactive content, allowing students to progress at their own pace and explore content as they found necessary. Completion of this asynchronous module series was required by incoming first-year students prior to the start of the academic semester. Following completion, students were asked to provide feedback on the module series. Reviews were primarily positive with students indicating that while the content was not entirely new, they found the review valuable and would be likely to reference the modules later in their genetic counseling training. Areas identified for improvement included additional detail regarding genetic testing methods as well as adjusting the interactive content to ensure accessibility for all students and systems. Taken together, the development and implementation of this asynchronous series as an additional component to genetic counseling training was considered a success and this approach can be considered to address additional topics dependent on a programs' needs.

Retrospective identification of patients with SRRM2-related neurodevelopmental disorder in a single tertiary children's hospital.

SRRM2-related neurodevelopmental disorder is a recently described genetic diagnosis caused by loss-of-function variants in SRRM2. In order to understand the clinical spectrum of SRRM2-related neurodevelopmental disorder, we performed a retrospective exome data and clinical chart review at a single tertiary children's hospital, Children's Hospital of Philadelphia (CHOP). Among approximately 3100 clinical exome sequencing cases performed at CHOP, we identified three patients with SRRM2 loss-of-function pathogenic variants, in addition to one patient previously described in the literature. Common clinical features include developmental delay, attention deficit hyperactivity disorder, macrocephaly, hypotonia, gastroesophageal reflux, overweight/obesity, and autism. While developmental disabilities are commonly seen in all individuals with SRRM2 variants, the degree of developmental delay and intellectual disability is variable. Our data suggest that SRRM2-related neurodevelopmental disorder can be identified in 0.3% of individuals with developmental disabilities receiving exome sequencing.

Identification of a novel nonsense mutation in the FOXP3 gene in a fetus with hydrops--Expanding the phenotype of IPEX syndrome.

IPEX Syndrome is a well-characterized, however rare, autoimmune condition primarily affecting males presenting with neonatal onset of severe diarrhea, diabetes, dermatitis, and other autoimmune symptoms. The gene responsible for this condition, FOXP3, is important in the function of T-regulatory cells which maintain tolerance to self-antigens and are implicated in many autoimmune conditions. While females who carry FOXP3 mutations are typically asymptomatic, pregnancy loss of male fetuses in families with a history of IPEX syndrome has been noted. This loss is likely unrelated to the maternal carrier status, and rather related to pathogenic fetal autoimmunity. Fetal presentation of IPEX Syndrome has been recently reported in two families. Of the two reported probands, one had onset of severe intrauterine growth restriction and the second involved monochorionic diamniotic twins affected with fetal hydrops. Loss of male fetuses was noted in both families. We present a third family who suffered the loss of two male fetuses as a result of fetal hydrops of an unknown etiology. Whole Exome Sequencing on fetal remains following the second loss identified a novel nonsense mutation in the FOXP3 gene, which was inherited from the mother and subsequently confirmed in saved cells from the first pregnancy. These two cases further expand the fetal phenotype of IPEX Syndrome. While rare, IPEX syndrome should be another potential differential when considering the onset of unexplained hydrops in a male fetus.

Recurrent De Novo Mutations Affecting Residue Arg138 of Pyrroline-5-Carboxylate Synthase Cause a Progeroid Form of Autosomal-Dominant Cutis Laxa.

Progeroid disorders overlapping with De Barsy syndrome (DBS) are collectively denoted as autosomal-recessive cutis laxa type 3 (ARCL3). They are caused by biallelic mutations in PYCR1 or ALDH18A1, encoding pyrroline-5-carboxylate reductase 1 and pyrroline-5-carboxylate synthase (P5CS), respectively, which both operate in the mitochondrial proline cycle. We report here on eight unrelated individuals born to non-consanguineous families clinically diagnosed with DBS or wrinkly skin syndrome. We found three heterozygous mutations in ALDH18A1 leading to amino acid substitutions of the same highly conserved residue, Arg138 in P5CS. A de novo origin was confirmed in all six probands for whom parental DNA was available. Using fibroblasts from affected individuals and heterologous overexpression, we found that the P5CS-p.Arg138Trp protein was stable and able to interact with wild-type P5CS but showed an altered sub-mitochondrial distribution. A reduced size upon native gel electrophoresis indicated an alteration of the structure or composition of P5CS mutant complex. Furthermore, we found that the mutant cells had a reduced P5CS enzymatic activity leading to a delayed proline accumulation. In summary, recurrent de novo mutations, affecting the highly conserved residue Arg138 of P5CS, cause an autosomal-dominant form of cutis laxa with progeroid features. Our data provide insights into the etiology of cutis laxa diseases and will have immediate impact on diagnostics and genetic counseling.

Atypical Williams syndrome in an infant with complete atrioventricular canal defect.

Williams-Beuren Syndrome (WBS) is a well-described microdeletion syndrome characterized by specific dysmorphic facial features, peripheral pulmonic stenosis, supravalvular aortic stenosis, hypercalcemia, feeding difficulties, gastroesophageal reflux, short stature, and specific intellectual disabilities (such as visual spatial problems). WBS is caused by 7q11.23 deletions that contain multiple genes known to contribute to the above phenotype. We report a neonate with a complete atrioventricular canal (CAVC) defect, an atypical cardiac lesion for WBS, and few typical phenotypic features of WBS, diagnosed at 20 days of life.