Citations

ABSTRACT Background Li Fraumeni syndrome (LFS) is a hereditary multi‐cancer syndrome caused by alterations in TP53 (MIM# 151623). Next generation sequencing (NGS) allows for the detection of TP53 variants at lower variant allele frequencies (VAFs). A TP53 variant with a VAF < 50% may represent mosaic LFS, aberrant clonal expansion (ACE), or possible circulating tumor DNA. Differentiation among these conditions is important for optimal patient management. Methods Genetic testing was performed using a custom gene panel, with an average read depth of 350× (range 166–553×). DNA extracted from four different tissues (blood, saliva, cultured skin fibroblasts, and colon) was sequenced. Results Here, we describe an adult female patient with a history of an adrenocortical neoplasm and osteosarcoma, diagnosed at 2 and 16 years of age, respectively. Testing of peripheral blood identified a pathogenic TP53 variant, c.733G>A, p.(Gly245Ser) (NM_000546.6); however, subsequent in vitro fertilization with preimplantation genetic testing for monogenic disorders (PGT‐M) did not identify this TP53 variant in any of nine embryos tested. Testing for possible mosaicism in the proband was performed on four different specimens, revealing variable VAFs of the TP53 variant (saliva: 44%; blood: 31%; cultured skin fibroblasts: 18%; and colon tissue: 9%). These results suggest a post‐zygotic event, consistent with mosaic LFS rather than ACE. Conclusion This case highlights the complexity of interpreting mosaic variants in the TP53 gene, and we propose a testing algorithm to aid in the delineation of this phenomenon when relaying cancer and reproductive risk information in the context of mosaicism.

ABSTRACT Background Chondrodysplasia punctata 1 (CDPX1) is an X‐linked recessive disorder of cartilage and bone development characterized by stippling on the cartilage and bone, flattened nasal bridge, and brachydactyly, or short fingers. CDPX1 has been associated with variants in the ARSL gene and is known to manifest prenatally, however, there has been no systematic literature review on this evidence. Aims Here, we reviewed the current literature on prenatal manifestations of CDPX1, and additionally introduce previously unpublished cases. Materials & Methods A systematic review of the literature was performed. Additionally, a GeneMatcher submission was created and a call for cases was presented at the Fetal Sequencing Consortium meetings to find previously unpublished cases. Results For the 22 fetuses reported here, we found that 55% had nasal hypoplasia, 41% had bony stippling or calcifications, 32% had polyhydramnios, 5% had oligohydramnios, 23% had shortened long bones, 23% had spinal canal stenosis, 18% had ventriculomegaly, 9% had brachydactyly/brachytelephalangy, 9% had clubbed feet, 9% had premature rupture of membranes, and 9% had intraventricular hemorrhage detected through sonography or radiography. We also found 17 unique variants in ARSL for these 22 fetuses. Discussion A previously unpublished association of ARSL variants with intrauterine fetal death or stillbirth has been noted in this study. It is also possible that intracranial hemorrhage is an underrecognized feature associated with CDPX1 variation. However, there have been challenges in applying ACMG criteria to ARSL, a gene without an associated Variant Curation Expert Panel. Conclusion This literature review and case series highlights which features of CDPX1 manifest prenatally, as well as introduces new phenotypes that have not been previously identified.

AbstractAxenfeld‐Rieger Syndrome (ARS) type 1 is a rare autosomal dominant condition characterized by anterior chamber anomalies, umbilical defects, dental hypoplasia, and craniofacial anomalies, with Meckel's diverticulum in some individuals. Here, we describe a clinically ascertained female of childbearing age with ARS for whom clinical targeted sequencing and deletion/duplication analysis followed by clinical exome and genome sequencing resulted in no pathogenic variants or variants of unknown significance in PITX2 or FOXC1. Advanced bioinformatic analysis of the genome data identified a complex, balanced rearrangement disrupting PITX2. This case is the first reported intrachromosomal rearrangement leading to ARS, illustrating that for patients with compelling clinical phenotypes but negative genomic testing, additional bioinformatic analysis are essential to identify subtle genomic abnormalities in target genes.

Abstract Career shadowing can be a valuable opportunity for individuals to experience the daily activities of a working professional. However, there is no published research regarding the impact of shadowing for individuals hoping to pursue a career as a genetic counselor (GC) (termed ‘shadowees’). Additionally, little is known about the impact of shadowing on practicing GCs, nor the value of shadowing in the application and admission process for genetic counseling graduate programs. For this study, three independent surveys were developed and sent to three stakeholder groups: shadowees in the Minnesota Genetic Counseling Experience Program, program directors within the Association of Genetic Counseling Program Directors, and members of the National Society of Genetic Counselors. Quantitative and qualitative analyses were performed on responses. The survey of shadowees ( n = 55) found that the majority believed that shadowing had either a ‘very’ or ‘somewhat positive’ impact on their decision to become a GC and on their application to a genetic counseling graduate program (81.8% and 91.3%, respectively). Of the participating program director respondents ( n = 43), the majority indicated that having shadowing experience was either ‘moderately’ or ‘extremely important’ in offering an interview or for acceptance into a graduate program (63% and 56%, respectively). While programs differ in evaluation of shadowing experiences, most program directors indicated that an applicant's ability to speak to their shadowing experience was the most important factor in admissions consideration (71%). Among the GCs surveyed ( n = 325), 69.2% have hosted shadowees; of these, 82.7% indicated that hosting a shadowee decreases their efficiency at work. Despite this drawback, the majority of respondents expressed a willingness and motivation to host shadowees to help the shadowee (64.8%) and to promote the genetic counseling profession (32.6%). These findings suggest the need for additional research and the development of resources for GCs to increase access of career shadowing.

AbstractGenetic counselors are trained to provide personalized genetic information and support to clients and their families. When requests for counseling comes from the counselor's own family member, should that counselor still provide service? There is a paucity of literature regarding genetic counselors counseling their own family members and no specific recommendations regarding how to reply to requests for genetic information from relatives. The purpose of this mixed methods study was to report genetic counselors’ and genetic counseling students’ perspectives and experiences providing genetic counseling to relatives. In the present study, 423 genetic counselors and genetic counseling students completed a 70‐item web‐based survey that explored genetic counselors’ experiences counseling family members outside of a clinic setting. The majority (73%; n = 301/410) of respondents have been asked to provide genetic counseling. Over half (57%; n = 257/423) provided counseling, personalized genetic information or risk assessment to family members. Only a small fraction of respondents (11%; n = 45/420) responded that they received any formal training in their graduate education, or in any other capacity that addressed the issue of how genetic counselors should respond to genetic counseling requests made family members. Those who have were less likely to provide genetic counseling to a family member (p < 0.05). Respondents who provided genetic counseling to relatives were significantly more likely to think their colleagues would do the same. Those who never provided genetic counseling to relatives were more likely to think their colleagues would refer to an unrelated genetic counselor (p < 0.0001). We highlight how our results have clinical and professional implications and provide suggestions to generate discussion among genetic counselors on how they might respond to requests for counseling from family members.