Personal journeys to and in human genetics and dysmorphology

Genetics has become a critical component of medicine over the past five to six decades. Alongside genetics, a relatively new discipline, dysmorphology, has also begun to play an important role in providing critically important diagnoses to individuals and families. Both have become indispensable to unraveling rare diseases. Almost every medical specialty relies on individuals experienced in these specialties to provide diagnoses for patients who present themselves to other doctors. Additionally, both specialties have become reliant on molecular geneticists to identify genes associated with human disorders. Many of the medical geneticists, dysmorphologists, and molecular geneticists traveled a circuitous route before arriving at the position they occupied. The purpose of collecting the memoirs contained in this article was to convey to the reader that many of the individuals who contributed to the advancement of genetics and dysmorphology since the late 1960s/early 1970s traveled along a journey based on many chances taken, replying to the necessities they faced along the way before finding full enjoyment in the practice of medical and human genetics or dysmorphology. Additionally, and of equal importance, all exhibited an ability to evolve with their field of expertise as human genetics became human genomics with the development of novel technologies.

The American Association for Thoracic Surgery (AATS) 2023 Expert Consensus Document: Recommendation for the care of children with trisomy 13 or trisomy 18 and a congenital heart defect

OBJECTIVES

Recommendations for surgical repair of a congenital heart defect in children with trisomy 13 or trisomy 18 remain controversial, are subject to biases, and are largely unsupported with limited empirical data. This has created significant distrust and uncertainty among parents and could potentially lead to suboptimal care for patients. A working group, representing several clinical specialties involved with the care of these children, developed recommendations to assist in the decision-making process for congenital heart defect care in this population. The goal of these recommendations is to provide families and their health care teams with a framework for clinical decision making based on the literature and expert opinions.

METHODS

This project was performed under the auspices of the AATS Congenital Heart Surgery Evidence-Based Medicine Taskforce. A Patient/Population, Intervention, Comparison/Control, Outcome process was used to generate preliminary statements and recommendations to address various aspects related to cardiac surgery in children with trisomy 13 or trisomy 18. Delphi methodology was then used iteratively to generate consensus among the group using a structured communication process.

RESULTS

Nine recommendations were developed from a set of initial statements that arose from the Patient/Population, Intervention, Comparison/Control, Outcome process methodology following the groups' review of more than 500 articles. These recommendations were adjudicated by this group of experts using a modified Delphi process in a reproducible fashion and make up the current publication. The Class (strength) of recommendations was usually Class IIa (moderate benefit), and the overall level (quality) of evidence was level C-limited data.

CONCLUSIONS

This is the first set of recommendations collated by an expert multidisciplinary group to address specific issues around indications for surgical intervention in children with trisomy 13 or trisomy 18 with congenital heart defect. Based on our analysis of recent data, we recommend that decisions should not be based solely on the presence of trisomy but, instead, should be made on a case-by-case basis, considering both the severity of the baby's heart disease as well as the presence of other anomalies. These recommendations offer a framework to assist parents and clinicians in surgical decision making for children who have trisomy 13 or trisomy 18 with congenital heart defect.

Causes of death in individuals with trisomy 18 after the first year of life

Mortality in individuals with trisomy 18 has significantly decreased over the past 20 years, but there is scant literature addressing the prognosis and cause of death in individuals with trisomy 18 and survival past the first year of life (YOL). This study analyzed factors associated with mortality and cause of death in a retrospective cohort of 174 individuals with trisomy 18 and survival past the first YOL, the largest such series to date. Data were collected via retrospective survey of parents of affected individuals. Prenatal diagnosis of trisomy 18; postnatal respiratory distress; maternal age > 35 years; birthweight <2000 g; brain and spinal cord defect(s); atrial and/or ventricular septal defect(s); inability to feed orally without medical assistance; and failure to meet sitting and rolling milestones were associated with mortality in this sample. Cause of death was compared between our cohort of individuals with trisomy 18 and existing literature on those with mortality before the first YOL. Individuals with trisomy 18 with mortality after the first YOL demonstrated a predominance of infectious (n = 10/22) and postoperative (n = 6/22) contributing causes of death, in contrast to the existing literature, which shows a predominance of cardiopulmonary causes of death (e.g., cardiopulmonary arrest, pulmonary hypertension). These findings demonstrate that individuals with trisomy 18 and survival past the first YOL have unique medical needs, but further research is needed to develop clinical guidelines for this growing population.

The common trisomy syndromes, their cardiac implications, and ethical considerations in care

PURPOSE OF REVIEW

To review the incidence of congenital heart disease in the trisomies, highlight the history of cardiac surgery in trisomy 21 comparing it to the increase in cardiac surgery in trisomies 13 and 18, discuss ethical issues specific to trisomies 13 and 18, and suggest a pathway of shared decision-making in the management of congenital heart disease in trisomy 13 and 18, specifically congenital heart surgery.

RECENT FINDINGS

Congenital heart disease is prevalent in the trisomies and the management of these defects, especially surgical intervention, has changed. In the late 20th century, survival after cardiac surgery in trisomy 21 vastly improved, significantly decreasing morbidity and mortality secondary to pulmonary hypertension. Similarly, procedures and surgeries have been performed with increasing frequency in trisomy 13 and 18 patients and concomitantly, survival in this patient population is increasing. Yet across the United States, the willingness to perform cardiac surgery in trisomy 13 and 18 is variable, and there is ethical controversy about the correct action to take. To address this concern, a shared decision-making approach with an informed parent(s) is advised.

SUMMARY

As the care and management of congenital heart disease changed in trisomy 21, so too it has with trisomy 13 and 18. Physicians and parents should develop goal-directed treatment plans balancing the risk versus benefit and consider cardiac surgical repair if feasible and beneficial.

SON-Related Zhu-Tokita-Takenouchi-Kim Syndrome With Recurrent Hemiplegic Migraine: Putative Role of PRRT2

Background and Objectives

Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome (OMIM 617140) is a recently identified neurodevelopmental disorder caused by heterozygous loss-of-function (LoF) variants in SON. Because the SON protein functions as an RNA-splicing regulator, it has been shown that some clinical features of ZTTK syndrome can be attributed to abnormal RNA splicing. Several neurologic features have been observed in patients with ZTTK syndrome, including seizure/epilepsy and other EEG abnormalities. However, a relationship between SON LoF in ZTTK syndrome and hemiplegic migraine remains unknown.

Methods

We identified a patient with a pathogenic variant in SON who shows typical clinical features of ZTTK syndrome and experienced recurrent episodes of hemiplegic migraine. To define clinical features, brain MRI and EEG during and after episodes of hemiplegic migraine were characterized. To identify molecular mechanisms for this clinical presentation, we investigated the impact of small interfering RNA (siRNA)-mediated SON knockdown on mRNA expression of the CACNA1A, ATP1A2, SCN1A, and PRRT2 genes, known to be associated with hemiplegic migraine, by quantitative RT-PCR. Pre-mRNA splicing of PRRT2 on SON knockdown was further examined by RT-PCR using primers targeting specific exons.

Results

Recurrent episodes of hemiplegic migraine in our patient typically followed modest closed head injuries, and recurrent seizures occurred during the most severe of these episodes. Transient hemispheric cortical interstitial edema and asymmetric EEG slowing were identified during episodes. Our siRNA experiments revealed that SON knockdown significantly reduces PRRT2 mRNA levels in U87MG and SH-SY5Y cell lines, although a reduction in CACNA1A, ATP1A2, and SCN1A mRNA expression was not observed. We further identified that SON knockdown leads to failure in intron 2 removal from PRRT2 pre-mRNA, resulting in a premature termination codon that blocks the generation of functionally intact full-length PRRT2.

Discussion

This report identifies recurrent hemiplegic migraine as a novel clinical manifestation of ZTTK syndrome, further characterizes this clinical feature, and provides evidence for downregulation of PRRT2 caused by SON LoF as a mechanism causing hemiplegic migraine. Examination of the SON gene may be indicated in individuals with recurrent hemiplegic migraine.

Prevalence and descriptive epidemiology of Turner syndrome in the United States, 2000-2017: A report from the National Birth Defects Prevention Network

The lack of United States population-based data on Turner syndrome limits assessments of prevalence and associated characteristics for this sex chromosome abnormality. Therefore, we collated 2000-2017 data from seven birth defects surveillance programs within the National Birth Defects Prevention Network. We estimated the prevalence of karyotype-confirmed Turner syndrome diagnosed within the first year of life. We also calculated the proportion of cases with commonly ascertained birth defects, assessed associations with maternal and infant characteristics using prevalence ratios (PR) with 95% confidence intervals (CI), and estimated survival probability. The prevalence of Turner syndrome of any pregnancy outcome was 3.2 per 10,000 female live births (95% CI = 3.0-3.3, program range: 1.0-10.4), and 1.9 for live birth and stillbirth (≥20 weeks gestation) cases (95% CI = 1.8-2.1, program range: 0.2-3.9). Prevalence was lowest among cases born to non-Hispanic Black women compared to non-Hispanic White women (PR = 0.5, 95% CI = 0.4-0.6). Coarctation of the aorta was the most common defect (11.6% of cases), and across the cohort, individuals without hypoplastic left heart had a five-year survival probability of 94.6%. The findings from this population-based study may inform surveillance practices, prenatal counseling, and diagnosis. We also identified racial and ethnic disparities in prevalence, an observation that warrants further investigation.

Seizures in trisomy 18: Prevalence, description, and treatment

Changes in medical intervention over the last decade have improved outcomes for individuals with trisomy 18, the second most common human aneuploidy syndrome at birth. As children with trisomy 18 live longer, a shared concern of medical experts and parents is the occurrence and treatment of seizures. Previously published surveillance guidelines for this condition have not addressed seizure management. Using parent-reported data collected as part of the Tracking Rare Incidence Syndromes project, we report on the prevalence, course, and management of seizures in individuals with trisomy 18. Twenty-eight percent (52/186) of individuals diagnosed with trisomy 18 in our retrospective cohort experienced generalized, focal, or mixed seizures at some point in their lifetime. For many individuals, seizures were effectively managed by broad-spectrum anti-seizure medications. Correlation analysis showed that focal and generalized seizures were more likely to occur in individuals who had previously experienced infantile spasms or central apnea. Electroencephalogram testing should be considered as part of a standard screening approach in individuals with trisomy 18 to enable early diagnosis and treatment of seizures. An international registry that incorporates parent-reported and clinical data for patients with trisomy 18 may facilitate ongoing research and recruitment into clinical trials for seizure management.

Prenatal patient perceptions of receiving difficult news over the telephone

Difficult news has been described as any news that adversely and seriously affects an individual's view of their future. Research in oncology genetic counseling demonstrated that individuals do not prefer in-person or telephone delivery of their genetic test results. However, in the prenatal setting, there is limited research examining how patients prefer news related to their pregnancies be disclosed. This study aimed to assess the experiences and preferences of prenatal patients who received difficult news by telephone. A semi-structured interview guide was developed to assess patients' personal definitions of difficult news and their experiences receiving the news by telephone. Fifteen patients seen prenatally by a genetic counselor were interviewed. Interviews were transcribed and consensus-coded, using inductive content analysis to identify several themes. The most common definition of difficult news included unexpected, life-changing, or devastating information. Participants described aspects of their experience and strategies employed by their genetic counselor that was helpful when receiving the news, which was found to align with the SPIKES protocol, a six-step process of delivering difficult news to patients. Additional techniques that participants identified as beneficial and satisfactory included the genetic counselor's use of empathy, non-directiveness, and continuity and coordination of care. Participants also provided recommendations for improvement, including a discussion of the mode of result disclosure during pretest counseling, an option to follow up with their genetic counselor, personalized resources, and a summary of the results call. The findings of this study demonstrate that a patient-centered approach is preferred by patients who receive difficult news by telephone in the prenatal setting. Patients' identification of beneficial communication techniques and suggestions for improvement can be implemented by any healthcare provider responsible for delivering difficult news to prenatal patients.

Evolution in the clinic: Maladaptive units and "minor anomalies"

It is here argued that the application of the term "minor anomalies" is often imprecise and likely outdated. In the past, the designation was used indiscriminately to refer to a great variety of unrelated morphogenetic phenomena. Also, the term does not discriminate between mild qualitative defects of development (mild malformations) and quantitative variants of normal structure. The human face was formed by natural and sexual selection. Morphological and morphogenetic analyses have shown that the human face with its skin, muscles, nerves, arteries, veins, glands, and lymphatics is a complex structure made up of progeny of ectoderm and mesoderm. Holoprosencephaly demonstrates graphically how these embryonic derivatives fit together sequentially. These derivatives are the adaptive units of the human organism, the result of stringent evolutionary forces uniting essential function to a minimum of structure. Before an "unusual" facial appearance is diagnosed as "abnormal", phenotype analysis is required to determine if there is a family resemblance or if it is a pleiotropic structure. The facial structures of chimps and humans are homologous by virtue of descent from a common ancestor (Darwin, 1859). Differences in the appearance of these species reflect adaptive divergence over some 6-7 million years of evolution while retaining over 98-99% genetic identity. Both species may develop Down syndrome, evidence of similarly retained developmental plasticity. It has occurred to us that Dobzhansky's axiom ("Nothing in biology makes sense except in the light of evolution") applies not only to genetics, but to all of medicine.

Teaching perspectives on the communication of difficult news of genetic conditions to medical students

Informing parents that their child has a diagnosis of Down syndrome (DS) is a common example of the delivery of unexpected or difficult news. Expectations and life planning will change, and if detected prenatally, discussions might include the option of pregnancy termination. Medical school curricula currently include training in breaking unexpected news; however, it is difficult to teach and assess. We use the perspectives of clinicians, educators, and a medical student who is the parent of a child with DS to frame a discussion on teaching, practicing, and assessing communication of difficult news in human genetics during medical school.

Elements of morphology: Standard terminology for the trunk and limbs

An international group of clinicians working in the field of dysmorphology has initiated the standardization of terms used to describe human morphology. The goals are to standardize these terms and reach consensus regarding their definitions. In this way, we will increase the utility of descriptions of the human phenotype and facilitate reliable comparisons of findings among patients. Additional discussions with other workers in dysmorphology and related fields, such as developmental biology and molecular genetics, will become more precise. Here we introduce the anatomy of the trunk and limbs and define and illustrate the terms that describe the major characteristics of these body regions.

Comprehensive variant calling from whole-genome sequencing identifies a complex inversion that disrupts ZFPM2 in familial congenital diaphragmatic hernia

BACKGROUND

Genetic disorders contribute to significant morbidity and mortality in critically ill newborns. Despite advances in genome sequencing technologies, a majority of neonatal cases remain unsolved. Complex structural variants (SVs) often elude conventional genome sequencing variant calling pipelines and will explain a portion of these unsolved cases.

METHODS

As part of the Utah NeoSeq project, we used a research-based, rapid whole-genome sequencing (WGS) protocol to investigate the genomic etiology for a newborn with a left-sided congenital diaphragmatic hernia (CDH) and cardiac malformations, whose mother also had a history of CDH and atrial septal defect.

RESULTS

Using both a novel, alignment-free and traditional alignment-based variant callers, we identified a maternally inherited complex SV on chromosome 8, consisting of an inversion flanked by deletions. This complex inversion, further confirmed using orthogonal molecular techniques, disrupts the ZFPM2 gene, which is associated with both CDH and various congenital heart defects.

CONCLUSIONS

Our results demonstrate that complex structural events, which often are unidentifiable or not reported by clinically validated testing procedures, can be discovered and accurately characterized with conventional, short-read sequencing and underscore the utility of WGS as a first-line diagnostic tool.

Management of Children with the Trisomy 18 and Trisomy 13 Syndromes: Is there a Shift in the Paradigm of Care?

OBJECTIVE

The conventional view toward the management of infants with the trisomy 18 and trisomy 13 syndromes has been to recommend pure comfort care and the avoidance of technological interventions. This commentary aims to address the recently raised question about whether there has been a shift in the paradigm of the management of infants with the two conditions.

STUDY DESIGN

The study design includes narrative review of the literature.

RESULTS

A body of opinion pieces and evidence has emerged indicating that there has been a recent increase in the administration of interventions, including ventilatory support and surgery, in the management of children with these syndromes.

CONCLUSION

Based on the evidence in the literature, the author concludes that there has been a type of paradigm shift described by philosopher of science, Thomas Kuhn, in the treatment of infants with trisomy 18 and 13. More parents are being offered and choosing technological interventions, including cardiac surgery. Future investigation of the question whether intervention improves outcome, including the quality of life, is crucial in addressing the unanswered questions in this dialogue.

KEY POINTS

· The conventional approach to the treatment of trisomy 18 and 13 has been to avoid interventions.. · There is a growing body of evidence that this traditional view of management is changing.. · Future investigation of whether intervention improves outcome is crucial in addressing the unanswered questions..

The delineation of the Wolf-Hirschhorn syndrome over six decades: Illustration of the ongoing advances in phenotype analysis and cytogenomic technology

Since Hirschhorn's description in 1961, the history and chronology of the clinical, cytogenetic, and molecular characterization of Wolf-Hirschhorn syndrome (WHS) elegantly demonstrates the remarkable advances in genetic technology over the last six decades that have paralleled the delineation of the phenotype. After mention in the Human Chromosome Newsletter of a child with a visible deletion of the top of a B chromosome group, 4-5, Hirschhorn and colleagues companioned their report with that of Wolf et al. in Humangenetik in 1965, and the condition was recognized and named. The 1960-1970s witnessed the description of many of the now classic chromosome disorders, including WHS, while HRB allowed for the recognition of chromosome syndromes with smaller deletions/duplications. FISH probes, developed in the next two decades, enabled the characterization of the critical region of WHS and improved clinical diagnosis with subtelomeric probes. Cytogenomic microarray in the early-mid 2000s led to both improved diagnosis of WHS patients and documentation of microdeletions of <5 megabases, helping to characterize the critical regions for specific component phenotypes (e.g., seizures, face). Recently exome sequencing technology has led to the discovery of WHS patients with WHSC1 loss of function variants, displaying some cardinal features of the phenotype (face, growth, and developmental delay).

Reflections on observing faces in art

The experience of art provides the visitor of a museum or gallery with the opportunity to contemplate and share the human condition both from the physical and psychological point of view. Because of the accessibility and the number of museums throughout Europe, classical European art as both sculpture and painting, affords the viewer the opportunity to experience life from one part of the world over centuries of history. These museums occasionally exhibit pieces showing a person with a human disorder and physical differences. On viewing such artwork, practitioners of health care, especially dysmorphologists, usually find themselves observing such pieces within the context of their practice. In this essay, the coauthors reflect on paintings and sculptures which remind us of our patients with similar physical and medical conditions. Various works of art also provide the opportunity to observe and view the human face from many vantage points and times in history. Several paintings are cited to illustrate the central themes of the Commentary: the human circumstance of disease and differences and the skill of observing and describing the human face.

Natural history study of adults with Wolf-Hirschhorn syndrome 2: Patient-reported outcomes study

Wolf-Hirschhorn syndrome (WHS) is a contiguous gene disorder consisting of prenatal and postnatal growth deficiency, distinctive craniofacial features, intellectual disability, and seizures. The condition is caused by a partial loss of material from the distal portion of the short arm of chromosome 4 (4p16.3). While there are many reports of individuals with WHS, useful data on long-term survival and life status of adults with the syndrome are very limited. There are only 11 reports of individuals over the age of 18 years in the literature. Establishing the medical manifestations of adults with WHS would be helpful in establishing appropriate health supervision guidelines. This study was one component of a two-part investigation on adults with WHS. This patient-reported outcomes study (PROS) was accomplished by using the registry of rare diseases at Sanford Research, Coordination of Rare Diseases (CoRDS)at Sanford. Thirty family members or caretakers of 30 adults with WHS/4p- entered into the CoRDS registry and completed some or all of the survey data. Twelve caretakers completed the recently-added survey on activities of daily living. Two of the individuals with WHS were partly independent while 10 required total care. The results provide novel information on daily life and independence in adults with WHS. Importantly, the majority of caretakers reported that the adults were in good health. The data from both parts of the study will contribute to our knowledge of the natural history of the syndrome and guide in establishing appropriate health supervision guidelines for adults with WHS.

Thinking outside "The Box": Case-based didactics for medical education and the instructional legacy of Dr John M. Graham, Jr

The increasing demand for advanced genomic services has finally come to the attention of healthcare systems and stakeholders who are now eager to find creative solutions to increase the pool of genomic literate providers. Training in genetics and dysmorphology has historically been conducted as a self-driven practice in pattern recognition, ideally within a formal or informal apprenticeship supervised by a master diagnostician. In recent times, case-based learning, framed by flipped classroom pedagogy have become the preferred teaching methods for complex medical topics such as genetics and genomics. To illuminate this perspective, our article was written in honor of the teaching style and pedagogy of Dr John M. Graham Jr and his lifelong commitment to medical education and mentoring.

Natural history study of adults with Wolf-Hirschhorn syndrome 1: Case series of personally observed 35 individuals

Wolf-Hirschhorn syndrome (WHS) is a contiguous gene disorder, clinically delineated by prenatal and postnatal growth deficiency, distinctive craniofacial features, intellectual disability, and seizures. The disorder is caused by partial loss of material from the distal portion of the short arm of chromosome 4 (4p16.3). Although more than 300 persons with WHS have been reported in the literature, there is sparse, if any, long-term follow-up of these individuals and thus little knowledge about course and potential further complications and health risks during adulthood and advanced age. This study attempted to assess medical conditions and function of adult individuals with WHS. It was one component of a two-part investigation on adults with WHS. The other part of the study is the patient-reported outcomes study reported elsewhere. About 35 individuals with WHS (26 females; nine males), aged between 19 and 55 years were recruited. About 25 individuals were personally observed at the IRCCS Stella Maris Foundation by A.B. and followed up between 5 and 20 years; and 10 were recruited from the 4p-Support Group, The United States. Of note, 23/35 (66%) are close to total care. About 11 out of 35 (31%) were partly self-independent, requiring supervision on certain daily routines, and 1 out of 35 (3%) was fully independent. However, a positive perspective is given by the overall good health enjoyed by the 66% of our cohort of individuals. Overall, quality of life and level of function into adulthood appear to be less critical than anticipated from previous studies.

Parent-reported histories of adults with trisomy 13 syndrome

Clinical histories and outcome data of long-term survivors with trisomy 13 are rare. The goal of this study was to collect the medical histories of adult individuals (≥18 years old) with apparent non-mosaic trisomy 13/Patau syndrome to help gain further insight in to the clinical course for individuals with this condition and to characterize the manifestations for surveillance and management. We collected 11 families through a contact person with the LWT13 (Living with Trisomy 13) LIFE support group. We performed telephone interviews to gather their medical histories and report these data in system-based summaries, tables, and clinical vignettes. In instances where parents retained copies of genetic testing reports or clinicians currently taking care of the individual with trisomy 13 were able to provide documentation, we confirmed diagnosis. All clinical histories and reported manifestations were consistent with a diagnosis of trisomy 13. We also elicited comments from parents on their personal experiences of raising an individual with trisomy 13.

Parent-authored memoirs: Lessons in the practice of narrative medicine

Healthcare professionals, including practitioners of medical genetics and genetic counseling, have much to learn about the experiences of parents who are raising and caring for a child with a rare disease or developmental disability. Knowledge and understanding of the challenges in the care of a child with conditions such as Down syndrome and Wolf-Hirschhorn syndrome are at the core of the practice of genetic medicine. Insights into this experience can come from active listening to stories and from deep reading of memoirs and narratives authored by parents of children having these challenges. A recent book, Raising a rare girl: A memoir, by writer, poet, and teacher, Heather Lanier, represents a relevant and prototypic example of this genre. Spending the effort in the contemplation of the parental stories provides a valuable lesson in narrative medicine and the experience of empathy for the plight of the family.

Novel de novo ARCN1 intronic variant causes rhizomelic short stature with microretrognathia and developmental delay

The archain 1 (ARCN1) gene encodes the coatomer subunit delta protein and is a component of the COPI coatomer complex, which is involved in retrograde vesical trafficking from the Golgi complex to the endoplasmic reticulum. Variants in ARCN1 have recently been associated with rhizomelic short stature with microcephaly, microretrognathia, and developmental delay. Here we report a 3.5-yr-old boy with microcephaly, global developmental delay, and multiple congenital abnormalities and the ARCN1-related syndrome caused by a novel de novo intronic variant. Whole-exome sequencing of the proband and his parents was utilized to determine the genetic origin of the patient's disorder and identified a de novo variant, NM_001655.5:c.654-15A > G, in the ARCN1 gene. Follow-up functional characterization of mRNA from the patient demonstrated that this variant creates a splicing defect of the ARCN1 mRNA. ARCN1-related syndrome represents an emerging disorder of developmental delay, and this report represents the sixth described patient. Despite the few instances reported in literature, the phenotype is consistent between our patient and previously reported individuals.

Experiences with offering pro bono medical genetics services in the West Indies: Benefits to patients, physicians, and the community

We describe our experiences with organizing pro bono medical genetics and neurology outreach programs on several different resource-limited islands in the West Indies. Due to geographic isolation, small population sizes, and socioeconomic disparities, most Caribbean islands lack medical services for managing, diagnosing, and counseling individuals with genetic disorders. From 2015 to 2019, we organized 2-3 clinics per year on various islands in the Caribbean. We also organized a week-long clinic to provide evaluations for children suspected of having autism spectrum disorder. Consultations for over 100 different individuals with suspected genetic disorders were performed in clinics or during home visits following referral by locally registered physicians. When possible, follow-up visits were attempted. When available and appropriate, clinical samples were shipped to collaborating laboratories for molecular analysis. Laboratory tests included karyotyping, cytogenomic microarray analysis, exome sequencing, triplet repeat expansion testing, blood amino acid level determination, biochemical assaying, and metabolomic profiling. We believe that significant contributions to healthcare by genetics professionals can be made even if availability is limited. Visiting geneticists may help by providing continuing medical education seminars. Clinical teaching rounds help to inform local physicians regarding the management of genetic disorders with the aim of generating awareness of genetic conditions. Even when only periodically available, a visiting geneticist may benefit affected individuals, their families, their local physicians, and the community at large.

Maternal diabetes-related malformations in Utah: A population study of birth prevalence 2001-2016

Maternal pregestational diabetes mellitus is associated with an increased risk for congenital malformations of about 2-4 times the background risk. Notably, the types and patterns of congenital malformations associated with maternal diabetes are nonrandom, with a well-established increased risk for specific classes of malformations, especially of the heart, central nervous system, and skeleton. While the increased risk in clinical and epidemiological studies is well documented in the literature, a precise estimate of overall birth prevalence of these specific congenital malformations among women with maternal pregestational diabetes, is lacking. The purpose of this study was to determine total prevalence of structural malformations associated with maternal pregestational diabetes mellitus in a population-based study. We identified infants with specific birth defects whose mother had pregestational diabetes mellitus in the Utah Birth Defect Network (UBDN), an active birth defects surveillance program that registers the occurrence of selected structural defects in the state of Utah. We defined specific maternal diabetes-related malformations based on epidemiologic and clinical studies in the literature. Of the 825,138 recorded Utah births between 2001 and 2016, a total of 91 cases were identified as likely having diabetic embryopathy within UBDN data. The prevalence of diabetes-related congenital malformation cases was calculated per year; the overall prevalence of diabetes-related malformations 2001-2016 was 1.1 per 10,000 births in Utah (95% CI, 0.9-1.3). Knowledge of the overall prevalence of diabetes-related malformations is important in predicting the number of cases that are potentially prevented with the implementation of programs to foster preconceptional management of maternal pregestational diabetes.

gene.iobio: an interactive web tool for versatile, clinically-driven variant interrogation and prioritization

With increasing utilization of comprehensive genomic data to guide clinical care, anticipated to become the standard of care in many clinical settings, the practice of diagnostic medicine is undergoing a notable shift. However, the move from single-gene or panel-based genetic testing to exome and genome sequencing has not been matched by the development of tools to enable diagnosticians to interpret increasingly complex genomic findings. A new paradigm has emerged, where genome-based tests are often evaluated by a large multi-disciplinary collaborative team, typically including a diagnostic pathologist, a bioinformatician, a genetic counselor, and often a subspeciality clinician. This team-based approach calls for new computational tools to allow every member of the clinical care provider team, at varying levels of genetic knowledge and diagnostic expertise, to quickly and easily analyze and interpret complex genomic data. Here, we present gene.iobio , a real-time, intuitive and interactive web application for clinically-driven variant interrogation and prioritization. We show gene.iobio is a novel and effective approach that significantly improves upon and reimagines existing methods. In a radical departure from existing methods that present variants and genomic data in text and table formats, gene.iobio provides an interactive, intuitive and visually-driven analysis environment. We demonstrate that adoption of gene.iobio in clinical and research settings empowers clinical care providers to interact directly with patient genomic data both for establishing clinical diagnoses and informing patient care, using sophisticated genomic analyses that previously were only accessible via complex command line tools.

Application of exome sequencing to diagnose a novel presentation of the Cornelia de Lange syndrome in an Afro-Caribbean family

BACKGROUND

Cornelia de Lange syndrome (CdLS) comprises a recognizable pattern of multiple congenital anomalies caused by variants of the DNA cohesion complex. Affected individuals may display a wide range of phenotypic severity, even within the same family.

METHODS

Exome sequencing and confirmatory Sanger sequencing showed the same previously described p.Arg629Ter NIPBL variant in two half-brothers affected with CdLS. Clinical evaluations were obtained in a pro bono genetics clinic.

RESULTS

One brother had relatively mild proportionate limb shortening; the other had complete bilateral hypogenesis of the upper arm with absence of lower arm structures, terminal transverse defects, and no digit remnants. His complex lower limb presentation included long bone deficiency and a deviated left foot. The mother had intellectual disability and microcephaly but lacked facial features diagnostic of the CdLS.

CONCLUSION

We describe a collaboration between a pediatrics team from a resource-limited nation and USA-based medical geneticists. Reports describing individuals of West Indian ancestry are rarely found in the medical literature. Here, we present a family of Afro-Caribbean ancestry with CdLS presenting with phenotypic variability, including unusual lower limb abnormalities. The observation of this novel family adds to our knowledge of the phenotypic and molecular aspects of CdLS.

Further delineation of the clinical spectrum of KAT6B disorders and allelic series of pathogenic variants

PURPOSE

Genitopatellar syndrome and Say-Barber-Biesecker-Young-Simpson syndrome are caused by variants in the KAT6B gene and are part of a broad clinical spectrum called KAT6B disorders, whose variable expressivity is increasingly being recognized.

METHODS

We herein present the phenotypes of 32 previously unreported individuals with a molecularly confirmed diagnosis of a KAT6B disorder, report 24 new pathogenic KAT6B variants, and review phenotypic information available on all published individuals with this condition. We also suggest a classification of clinical subtypes within the KAT6B disorder spectrum.

RESULTS

We demonstrate that cerebral anomalies, optic nerve hypoplasia, neurobehavioral difficulties, and distal limb anomalies other than long thumbs and great toes, such as polydactyly, are more frequently observed than initially reported. Intestinal malrotation and its serious consequences can be present in affected individuals. Additionally, we identified four children with Pierre Robin sequence, four individuals who had increased nuchal translucency/cystic hygroma prenatally, and two fetuses with severe renal anomalies leading to renal failure. We also report an individual in which a pathogenic variant was inherited from a mildly affected parent.

CONCLUSION

Our work provides a comprehensive review and expansion of the genotypic and phenotypic spectrum of KAT6B disorders that will assist clinicians in the assessment, counseling, and management of affected individuals.

40th Annual David W Smith Workshop on Malformations and Morphogenesis: Abstracts of the 2019 Annual Meeting

The 40th Annual David W. Smith Workshop on Malformations and Morphogenesis occurred August 23rd -28th, 2019 at the Snowbird Resort in Snowbird, Utah. The Workshop, which honors the legacy of David W. Smith, brought together clinicians and researchers interested in congenital malformations and their underlying mechanisms of morphogenesis from around the world. In addition to mechanisms of morphogenesis and delineation of new syndromes, the Workshop highlighted five themes: deformations, disruptions and fetal dysmorphology; orofacial clefting; central nervous system malformations; ciliopathies; and X-linked intellectual disabilities. This Conference Report includes the abstracts presented at the 2019 Workshop.

Osteoporosis and skeletal dysplasia caused by pathogenic variants in SGMS2

Mechanisms leading to osteoporosis are incompletely understood. Genetic disorders with skeletal fragility provide insight into metabolic pathways contributing to bone strength. We evaluated 6 families with rare skeletal phenotypes and osteoporosis by next-generation sequencing. In all the families, we identified a heterozygous variant in SGMS2, a gene prominently expressed in cortical bone and encoding the plasma membrane–resident sphingomyelin synthase SMS2. Four unrelated families shared the same nonsense variant, c.148C>T (p.Arg50*), whereas the other families had a missense variant, c.185T>G (p.Ile62Ser) or c.191T>G (p.Met64Arg). Subjects with p.Arg50* presented with childhood-onset osteoporosis with or without cranial sclerosis. Patients with p.Ile62Ser or p.Met64Arg had a more severe presentation, with neonatal fractures, severe short stature, and spondylometaphyseal dysplasia. Several subjects had experienced peripheral facial nerve palsy or other neurological manifestations. Bone biopsies showed markedly altered bone material characteristics, including defective bone mineralization. Osteoclast formation and function in vitro was normal. While the p.Arg50* mutation yielded a catalytically inactive enzyme, p.Ile62Ser and p.Met64Arg each enhanced the rate of de novo sphingomyelin production by blocking export of a functional enzyme from the endoplasmic reticulum. SGMS2 pathogenic variants underlie a spectrum of skeletal conditions, ranging from isolated osteoporosis to complex skeletal dysplasia, suggesting a critical role for plasma membrane–bound sphingomyelin metabolism in skeletal homeostasis.

The identification of 6 families with childhood-onset osteoporosis with mutations in SGMS2 suggests a critical role for plasma membrane–bound sphingomyelin metabolism in skeletal homeostasis.

Bi-allelic Variants in TONSL Cause SPONASTRIME Dysplasia and a Spectrum of Skeletal Dysplasia Phenotypes

SPONASTRIME dysplasia is an autosomal-recessive spondyloepimetaphyseal dysplasia characterized by spine (spondylar) abnormalities, midface hypoplasia with a depressed nasal bridge, metaphyseal striations, and disproportionate short stature. Scoliosis, coxa vara, childhood cataracts, short dental roots, and hypogammaglobulinemia have also been reported in this disorder. Although an autosomal-recessive inheritance pattern has been hypothesized, pathogenic variants in a specific gene have not been discovered in individuals with SPONASTRIME dysplasia. Here, we identified bi-allelic variants in TONSL, which encodes the Tonsoku-like DNA repair protein, in nine subjects (from eight families) with SPONASTRIME dysplasia, and four subjects (from three families) with short stature of varied severity and spondylometaphyseal dysplasia with or without immunologic and hematologic abnormalities, but no definitive metaphyseal striations at diagnosis. The finding of early embryonic lethality in a Tonsl-/- murine model and the discovery of reduced length, spinal abnormalities, reduced numbers of neutrophils, and early lethality in a tonsl-/- zebrafish model both support the hypomorphic nature of the identified TONSL variants. Moreover, functional studies revealed increased amounts of spontaneous replication fork stalling and chromosomal aberrations, as well as fewer camptothecin (CPT)-induced RAD51 foci in subject-derived cell lines. Importantly, these cellular defects were rescued upon re-expression of wild-type (WT) TONSL; this rescue is consistent with the hypothesis that hypomorphic TONSL variants are pathogenic. Overall, our studies in humans, mice, zebrafish, and subject-derived cell lines confirm that pathogenic variants in TONSL impair DNA replication and homologous recombination-dependent repair processes, and they lead to a spectrum of skeletal dysplasia phenotypes with numerous extra-skeletal manifestations.

Mortality and Resource Use Following Cardiac Interventions in Children with Trisomy 13 and Trisomy 18 and Congenital Heart Disease

We sought to evaluate the mortality, risk factors for mortality, and resource utilization following cardiac interventions in trisomy 13 (T13) and 18 (T18) children. All T13 and T18 children who underwent a cardiac intervention from January 1999 to March 2015 were identified from the Pediatric Health Information System database. Data collected included demographics, type of congenital heart disease (CHD), cardiac interventions, comorbidities, length of stay (LOS), hospital charges, and deaths (within 30 days). Logistic regression analysis was used to determine factors associated with mortality. There were 49 (47% females) T13 and 140 (67% females) T18 subjects. The two cohorts were similar in distribution for race, geographic region, insurance type, and median household income. The most common CHD in both groups was a shunt lesion followed by conotruncal defects. Compared to T18, the T13 cohort had higher mortality (29% vs. 12%), tracheostomies (12% vs. 4%), gastrostomies (18% vs. 6%), and overall resource use (P < 0.05 for all). White race (OR 0.23, 95% CI 0.06-0.81) in T13 and older age (in weeks) at surgery in T18 (OR 0.75, 95% CI 0.64-0.86) were associated with lower mortality. A select group of T13 and T18 CHD patients can undergo successful cardiac interventions, albeit with a higher mortality and resource use. T13 patients have higher mortality and resource use compared to T18. In T13 and T18 patients, interventions for CHD may be an acceptable and ethical option following a careful individualized selection and counseling by a team of experts.

Multiple Congenital Anomalies and Global Developmental Delay in a Patient with Interstitial 6q25.2q26 Deletion: A Diagnostic Odyssey

Interstitial deletions involving 6q25 are rare chromosomal abnormalities associated with distinctive phenotypic features. We describe a 9-year-old boy who was followed from his infancy due to his multiple congenital anomalies and complex medical history. Over the years, a number of diagnoses were considered including Cornelia de Lange syndrome, Rubinstein-Taybi syndrome, as well as "a novel genetic disorder." Various genetic tests, including a BAC-based array-CGH analysis, were reported as normal. Recently, a SNP-based microarray analysis was performed and showed an 11.1-Mb deletion from 6q25.2 to 6q26, including ARID1B and ZDHHC14. Recent literature suggests that the 6q25 deletion syndrome is a recognizable entity characterized by growth delay, developmental disabilities, microcephaly, hearing loss, and variable other malformations including cleft palate. These features overlap with those of Coffin-Siris syndrome, which is caused by deletions and loss-of-function mutations of ARID1B. Retrospectively, this patient has features resembling both Coffin-Siris and 6q25 microdeletion syndromes.

Risk of hepatic neoplasms in Wolf-Hirschhorn syndrome (4p-): Four new cases and review of the literature

Wolf-Hirschhorn syndrome (WHS) is a rare contiguous gene deletion disorder characterized by distinctive craniofacial features, prenatal/postnatal growth deficiency, intellectual disability, and seizures. Various malformations of internal organs are also seen. Neoplasia has not been documented as a typical feature of WHS. We review the three prior reports of hepatic neoplasia in WHS and add four previously unreported individuals. We propose that, in the context of the rarity of WHS, these seven cases suggest that hepatocellular neoplasia may be a feature of WHS.