Dual diagnosis of autosomal dominant polycystic kidney disease and sickle cell disease in a teenage male

BACKGROUND

Sickle cell disease (SCD) and autosomal dominant polycystic kidney disease (ADPKD) are relatively common genetic conditions with considerable overlap in clinical presentation. In addition to similarities between the signs and symptoms in sickle cell nephropathy and ADPKD, more than half of SCD patients have kidney cysts. The co-occurrence of these two diseases has not been previously reported in the literature.

CASE DIAGNOSIS/TREATMENT

A 16-year-old Black male with SCD had bilateral kidney enlargement and multiple simple cysts on ultrasound. Although kidney cysts are significantly more common in individuals affected with SCD, genetic testing with a broad kidney gene panel was performed to explore the possible presence of another underlying genetic cause of his cysts, in addition to SCD. A dual diagnosis of SCD and ADPKD was made following the identification of two copies of the common pathogenic sickle cell HBB variant (c.20A > T, p.Glu7Val) and a pathogenic missense variant in PKD1 (c.8311G > A, p.Glu2771Lys).

CONCLUSIONS

SCD and ADPKD differ in pathophysiological mechanisms and treatment regimens. As such, it will be paramount for this teenager to be closely monitored for signs of diminished kidney function and to be co-managed as he transitions to adult care to ensure proper treatment and management. Early identification of individuals with both SCD and a co-occurring condition is crucial to ensuring proper clinical management. Furthermore, identifying and reporting additional patients with SCD and ADPKD dual diagnoses will help us to understand the co-occurring disease course and optimal treatments.

Genetic Counseling in Kidney Disease: A Perspective

As genetic testing is increasingly integrated into nephrology practice there is a growing need for partnership with genetic experts. Genetic counselors are ideally suited to fill this role. The value of genetic counseling is born out of the clinical value of genetic test results against the backdrop of the complexity of genetic testing. Genetic counselors who specialize in nephrology are trained to understand and explain the potential effects of genes on kidney disease, which can enable patients to make informed decisions about proceeding with genetic testing, navigating variants of uncertain significance, educating on extrarenal features of hereditary kidney disease, facilitating cascade testing, providing post-test education about testing results, and assisting with family planning. Genetic counselors can partner with the nephrologist and provide the knowledge needed to maximize the use of genetic testing for patients for nephrology consultation. Genetic counseling is more than an element or extension of genetic testing; it is a dynamic, shared conversation between the patient and the genetic counselor where concerns, sentiments, information, and education are exchanged, and value-based decision making is facilitated.

Isolated benign persistent proteinuria with novel association of CUBN (cubilin) variants

We present two siblings with persistent proteinuria and normal kidney function, each carrying the same compound heterozygous variants in the CUBN gene. The CUBN-related phenotype appears to be dependent upon both variant type and the domain site within the gene. Knowledge of CUBN status may allow for avoidance of invasive testing.

The State of Newborn Screening in South Dakota

South Dakota's Newborn Screening (NBS) program has been in existence for nearly 50 years. What began as a screen for a single condition has now expanded to more than 50 conditions. From 2005-2019 alone, 315 infants were confirmed as positive for a condition detected by the newborn screen in South Dakota. This article summarizes the process of newborn screening in South Dakota, the role of the primary care physician when caring for an infant with a positive screen, the groups of conditions which are included on the South Dakota NBS panel, how NBS changed over time, and the process for adding conditions to the South Dakota NBS panel.

Genesurance counseling: Current training practices of genetic counseling graduate programs in the United States

In recent years, it has become apparent that patients expect genetic counselors to be able to address questions about insurance coverage for genetic testing and perform 'genesurance' tasks in and out of genetic counseling sessions. Anecdotally, many genetic counseling graduate programs have begun to incorporate genesurance training in some capacity. However, the amount, modality, and potential barriers to this training had not been previously studied; therefore, this study aimed to elucidate current graduate program practice regarding genesurance. Program Directors of Accreditation Council for Genetic Counseling (ACGC) accredited programs who had students enrolled as of July 2019 (n = 50) were recruited through the Association of Genetic Counseling Program Directors (AGCPD) listserv and invited to complete an anonymous electronic survey via Qualtrics. Program Directors (PDs) from 25 ACGC accredited programs located in the United States completed the survey and were included in the analysis, responses from two ACGC Canadian programs were excluded due to small sample size and differences in healthcare systems. Responses were analyzed using descriptive statistics and open-ended responses were coded utilizing latent qualitative content analysis. The majority of respondents from the United States, 96.0% (24/25), report incorporating genesurance training into their curriculum utilizing a variety of training modalities including classroom, clinical, and online experiences. Most (81.0%) felt their trainees were adequately or very prepared to discuss genesurance issues. Despite varied methods of teaching modalities, PDs identified barriers to providing this training, including time constraints within the curriculum, lack of interest in the subject, as well as acknowledging the constantly changing landscape of billing and insurance. Despite these barriers, a baseline understanding of the impact of insurance on offering genetic testing and insight into how insurance impacts clinical practice may be beneficial to genetic counseling trainees, as it reflects the current genetic counselor's workflow and practice patterns.

Perspectives of Pediatric Providers Regarding Clinical Use of Pharmacogenetics

INTRODUCTION

A major goal of the current personalized medicine era is to utilize pharmacogenetics (PGx) in order to influence how medications and therapies are prescribed by providers. However, disparities for prescribing medications between adults and children exist. Research has shown that children are not just small adults and there are different challenges for pediatric providers in regards to ordering and interpreting PGx tests. The goal of this study was to obtain an initial understanding of current pharmacogenetic testing by pediatric providers, as well as determine perceived barriers.

METHODS

We distributed an online survey to pediatric providers at six different institutions across the U.S.

RESULTS

Of the 252 respondents who completed the survey, 24 percent reported previously ordering PGx tests, however, over 90 percent of respondents reported they would feel more comfortable ordering and interpreting results with the assistance of a pharmacist, geneticist, genetic counselor or PGx expert. Additionally, participants identified specific barriers towards the utilization of PGx testing, as well as suggested solutions to overcome these barriers, including increasing provider education regarding testing, collaboration through a multidisciplinary team approach and established PGx programs.

CONCLUSION

As the pharmacogenetic field continues to demonstrate clinical utility in the pediatric population, it will be important to continuously identify and address barriers that exist for providers to allow for more successful implementation of PGx in the pediatric setting, as well as enhance patient care.

Geographical analysis of the distribution of certified genetic counselors in the United States

The number of certified genetic counselors (CGCs) in the genetic counseling workforce has increased over the past few decades as the number of training programs increases and CGCs expand into new patient-facing and non-patient-facing roles. Few studies have explored the distribution of CGCs across the United States. We sought to identify the U.S. geographical regions with the highest number of CGCs and those regions where the physical presence of CGCs is sparser. Deidentified city, state, and ZIP code information for each CGC in the United States were obtained from the American Board of Genetic Counseling (ABGC) database. A countrywide analysis of the distribution of CGCs was completed using geographic information system (GIS) mapping software. The data were organized into U.S. metropolitan or micropolitan statistical areas, if applicable, and analyzed by CGC per capita. We included a total of 4,554 data points (92.2%) in the analysis. Results showed there is one CGC for every 71,842 people nationwide. Of 3,141 total counties (or county equivalents) in the United States, 535 counties had at least one CGC (17.0%). The majority (98.7%) of CGCs live or work within metropolitan statistical areas (MSAs), which are defined by this study as geographical areas with greater than 50,000 people. Of the MSAs with a CGC, approximately half have more than one CGC per 100,000 people. These results are consistent with the overall distribution of the U.S. population. We believe that the MSAs with the most CGCs per capita are due to associations with specific institutions, that is, genetic counseling training programs, health system headquarters, or genetic laboratories. Although the present study cannot draw definite conclusions regarding direct patient care services provided by CGCs, it does provide a snapshot of current CGC distribution within the country. Knowing the distribution of CGCs provides a tool to conduct further workforce analyses to determine the number of CGCs needed to serve the U.S. population.

Genetic Counseling in Middle School Science Club: A Pilot Study

Compared to demographic data from other healthcare professions, genetic counselors (GCs) are more likely to be Caucasian females. Many current underrepresented in genetic counseling (URGC) professionals in the field found genetic counseling later in their careers due in part to their lack of awareness. A pilot study consisting of equal numbers of male and female sixth grade science club students was conducted to explore the impact that direct teaching might have on students' awareness of and interest in genetic counseling. The analysis used the non-parametric Wilcoxon signed rank test due to the ordinal, Likert-scale data. Results derived from a pre- and post-survey of lesson participants indicated a statistically significant increase in students' perceptions of having a role model in a science career. Efforts to reach local middle school students to highlight genetic counseling as a potential career choice, especially by role models, may add to the continued work being done to increase the diversity of future genetic counseling applicant pools.

Genetic Counseling in Pediatrics

Genetic counseling is a communication process whereby an individual or family obtains information about a genetic condition, is helped to understand the implications and significance of the condition, and is given resources to help with coping and management. It is a continuous process involving lasting supportive relationships between the family and the genetic professional. Genetic counselors are master's level-trained health-care professionals who work closely with pediatricians and pediatric subspecialists alike. Genetic counselors can be a source of information about genetic conditions, risk assessment for disease, and genetic testing. Although most of a genetic counselor's job is patient care and education, genetic counselors also serve as resources to educate health professionals about genetics.

Natural history and genotype-phenotype correlations in 72 individuals with SATB2-associated syndrome

SATB2-associated syndrome (SAS) is an autosomal dominant disorder characterized by significant neurodevelopmental disabilities with limited to absent speech, behavioral issues, and craniofacial anomalies. Previous studies have largely been restricted to case reports and small series without in-depth phenotypic characterization or genotype-phenotype correlations. Seventy two study participants were identified as part of the SAS clinical registry. Individuals with a molecularly confirmed diagnosis of SAS were referred after clinical diagnostic testing. In this series we present the most comprehensive phenotypic and genotypic characterization of SAS to date, including prevalence of each clinical feature, neurodevelopmental milestones, and when available, patient management. We confirm that the most distinctive features are neurodevelopmental delay with invariably severely limited speech, abnormalities of the palate (cleft or high-arched), dental anomalies (crowding, macrodontia, abnormal shape), and behavioral issues with or without bone or brain anomalies. This comprehensive clinical characterization will help clinicians with the diagnosis, counseling and management of SAS and help provide families with anticipatory guidance.

High Rate of Recurrent De Novo Mutations in Developmental and Epileptic Encephalopathies

Developmental and epileptic encephalopathy (DEE) is a group of conditions characterized by the co-occurrence of epilepsy and intellectual disability (ID), typically with developmental plateauing or regression associated with frequent epileptiform activity. The cause of DEE remains unknown in the majority of cases. We performed whole-genome sequencing (WGS) in 197 individuals with unexplained DEE and pharmaco-resistant seizures and in their unaffected parents. We focused our attention on de novo mutations (DNMs) and identified candidate genes containing such variants. We sought to identify additional subjects with DNMs in these genes by performing targeted sequencing in another series of individuals with DEE and by mining various sequencing datasets. We also performed meta-analyses to document enrichment of DNMs in candidate genes by leveraging our WGS dataset with those of several DEE and ID series. By combining these strategies, we were able to provide a causal link between DEE and the following genes: NTRK2, GABRB2, CLTC, DHDDS, NUS1, RAB11A, GABBR2, and SNAP25. Overall, we established a molecular diagnosis in 63/197 (32%) individuals in our WGS series. The main cause of DEE in these individuals was de novo point mutations (53/63 solved cases), followed by inherited mutations (6/63 solved cases) and de novo CNVs (4/63 solved cases). De novo missense variants explained a larger proportion of individuals in our series than in other series that were primarily ascertained because of ID. Moreover, these DNMs were more frequently recurrent than those identified in ID series. These observations indicate that the genetic landscape of DEE might be different from that of ID without epilepsy.

Case Report of Infant With Features of Beckwith-Wiedemann Syndrome Diagnosed With Genome-wide Uniparental Disomy

Uniparental disomy (UPD), where two copies of genetic material are from one parent, and none from the other, is a familiar cause of imprinting. We present a premature infant with organomegaly and congenital hyperinsulinism found to have complete UPD of paternal origin as determined by Mendelian inheritance error analysis.

Further supporting evidence for the SATB2-associated syndrome found through whole exome sequencing

The SATB2-associated syndrome (SAS) was recently proposed as a clinically recognizable syndrome that results from deleterious alterations of the SATB2 gene in humans. Although interstitial deletions at 2q33 encompassing SATB2, either alone or contiguously with other genes, have been reported before, there is limited literature regarding intragenic mutations of this gene and the resulting phenotype. We describe five patients in whom whole exome sequencing identified five unique de novo mutations in the SATB2 gene (one splice site, one frameshift, and three nonsense mutations). The five patients had overlapping features that support the characteristic features of the SAS: intellectual disability with limited speech development and craniofacial abnormalities including cleft palate, dysmorphic features, and dental abnormalities. Furthermore, Patient 1 also had features not previously described that represent an expansion of the phenotype. Osteopenia was seen in two of the patients, suggesting that this finding could be added to the list of distinctive findings. We provide supporting evidence that analysis for deletions or point mutations in SATB2 should be considered in children with intellectual disability and severely impaired speech, cleft or high palate, teeth abnormalities, and osteopenia.

Mutations in DDX3X Are a Common Cause of Unexplained Intellectual Disability with Gender-Specific Effects on Wnt Signaling

Intellectual disability (ID) affects approximately 1%-3% of humans with a gender bias toward males. Previous studies have identified mutations in more than 100 genes on the X chromosome in males with ID, but there is less evidence for de novo mutations on the X chromosome causing ID in females. In this study we present 35 unique deleterious de novo mutations in DDX3X identified by whole exome sequencing in 38 females with ID and various other features including hypotonia, movement disorders, behavior problems, corpus callosum hypoplasia, and epilepsy. Based on our findings, mutations in DDX3X are one of the more common causes of ID, accounting for 1%-3% of unexplained ID in females. Although no de novo DDX3X mutations were identified in males, we present three families with segregating missense mutations in DDX3X, suggestive of an X-linked recessive inheritance pattern. In these families, all males with the DDX3X variant had ID, whereas carrier females were unaffected. To explore the pathogenic mechanisms accounting for the differences in disease transmission and phenotype between affected females and affected males with DDX3X missense variants, we used canonical Wnt defects in zebrafish as a surrogate measure of DDX3X function in vivo. We demonstrate a consistent loss-of-function effect of all tested de novo mutations on the Wnt pathway, and we further show a differential effect by gender. The differential activity possibly reflects a dose-dependent effect of DDX3X expression in the context of functional mosaic females versus one-copy males, which reflects the complex biological nature of DDX3X mutations.

Mutations in QARS, encoding glutaminyl-tRNA synthetase, cause progressive microcephaly, cerebral-cerebellar atrophy, and intractable seizures

Progressive microcephaly is a heterogeneous condition with causes including mutations in genes encoding regulators of neuronal survival. Here, we report the identification of mutations in QARS (encoding glutaminyl-tRNA synthetase [QARS]) as the causative variants in two unrelated families affected by progressive microcephaly, severe seizures in infancy, atrophy of the cerebral cortex and cerebellar vermis, and mild atrophy of the cerebellar hemispheres. Whole-exome sequencing of individuals from each family independently identified compound-heterozygous mutations in QARS as the only candidate causative variants. QARS was highly expressed in the developing fetal human cerebral cortex in many cell types. The four QARS mutations altered highly conserved amino acids, and the aminoacylation activity of QARS was significantly impaired in mutant cell lines. Variants p.Gly45Val and p.Tyr57His were located in the N-terminal domain required for QARS interaction with proteins in the multisynthetase complex and potentially with glutamine tRNA, and recombinant QARS proteins bearing either substitution showed an over 10-fold reduction in aminoacylation activity. Conversely, variants p.Arg403Trp and p.Arg515Trp, each occurring in a different family, were located in the catalytic core and completely disrupted QARS aminoacylation activity in vitro. Furthermore, p.Arg403Trp and p.Arg515Trp rendered QARS less soluble, and p.Arg403Trp disrupted QARS-RARS (arginyl-tRNA synthetase 1) interaction. In zebrafish, homozygous qars loss of function caused decreased brain and eye size and extensive cell death in the brain. Our results highlight the importance of QARS during brain development and that epilepsy due to impairment of QARS activity is unusually severe in comparison to other aminoacyl-tRNA synthetase disorders.

Identification of a founder mutation for maple syrup urine disease in Hutterites

Maple syrup urine disease (MSUD) is an organic acidemia detected on newborn screening. The condition has been reported with increased frequency in certain founder populations including Hutterites. We present a case of MSUD in a Hutterite boy. Mutation analysis was completed and identified a candidate founder mutation in the BCKDHB gene, specifically c.595_596delAG. Further testing of other Hutterites with MSUD is needed to determine whether additional mutations may exist.

Congenital nasal pyriform aperture stenosis and ocular albinism co-occurring in a sibship with a maternally-inherited 97 kb Xp22.2 microdeletion

Congenital Nasal Pyriform Aperture Stenosis (CNPAS) is a rare congenital malformation caused by overgrowth of the maxillary bone. We report on two patients, brothers born 3 and 1½ years apart, both presented at birth with radiographically diagnosed CNPAS. Both siblings also were born with ocular albinism, which is known to have X-linked inheritance. Subsequent genetic testing demonstrated a 97 kb deletion in the p arm of the X chromosome in both siblings and their mother. This deletion encompasses a gene known to cause ocular albinism (GPR143), as well as partial deletion of two other genes, TBL1X and SHROOM2. This is the first reported case of CNPAS in siblings, both males, sharing a maternally inherited Xp22.2 deletion.

Blepharophimosis-ptosis-epicanthus inversus syndrome and hypergonadotropic hypogonadism

OBJECTIVE

To describe a woman with blepharophimosis-ptosis-epicanthus inversus syndrome and hypergonadotropic hypogonadism.

DESIGN

Case report.

SETTING

University medical center.

PATIENT(S)

One 25-year-old woman.

INTERVENTION(S)

Pedigree, hormone assays, and donor embryo transfer.

MAIN OUTCOME MEASURE(S)

Pregnancy.

RESULT(S)

The patient with hypergonadtropic hypogonadism obtained an ongoing pregnancy after donor embryo transfer.

CONCLUSION(S)

Blepharophimosis-ptosis-epicanthus inversus syndrome is associated with evidence of premature ovarian failure. The syndrome is a sex-limited, autosomal dominant trait that causes selective loss of ovarian function in affected females. This report emphasizes the importance of a thorough family history and pedigree analysis in the evaluation of a patient with hypergonadotropic hypogonadism.

Clinical course of a 20-month-old child diagnosed prenatally with mosaic ring chromosome 18 and monosomy 18

We report on a 20-month-old male, diagnosed prenatally with de novo mosaic ring chromosome 18 and low level monosomy 18, who also exhibited an inherited and apparently balanced translocation between chromosomes 3 and 6. We believe this to be the first reported case of prenatally diagnosed mosaic ring chromosome 18 and monosomy 18 in which the child was carried to term. Ring chromosomes are associated with an abnormal phenotype that is dependent on the amount of material that is deleted from the p and q arms. This child has a 22.5 Mb deletion of 18q and a 2.8 Mb deletion of 18p as a result of ring formation. Although the large deletion has resulted in some developmental delays and health problems, the child is making more developmental progress than was anticipated prenatally. We present his clinical course and the genetic counseling challenges associated with this case.

Premature ovarian failure: a phenotypic expression of fragile X premutation

Fragile X syndrome is the most common cause of mental retardation in the male. Historically, fragile X premutation was considered to be phenotypically silent. In recent reports the premutation has been associated with premature ovarian failure and fragile X-associated tremor/ataxia syndrome. This case describes a 24-year-old woman who presented with irregular menstrual cycles secondary to premature ovarian failure. Subsequent genetic analysis confirmed that she has a premutation for fragile X with 70 CGG trinucleotide repeats.

Variations in IBD (ACAD8) in children with elevated C4-carnitine detected by tandem mass spectrometry newborn screening

The isobutyryl-CoA dehydrogenase (IBD) enzyme is involved in the degradation of valine. IBD deficiency was first reported in 1998 and subsequent genetic investigations identified acyl-CoA dehydrogenase (ACAD) 8, now IBD, as the gene responsible for IBD deficiency. Only three individuals homozygous or compound heterozygous for variations in the IBD gene have been reported. We present IBD deficiency in an additional four newborns with elevated C(4)-carnitine identified by tandem mass spectrometry (MS/MS) screening in Denmark and the United States. Three showed urinary excretions of isobutyryl-glycine, and in vitro probe analysis of fibroblasts from two newborns indicated enzymatic IBD defect. Molecular genetic analysis revealed seven new rare variations in the IBD gene (c.348C>A, c.400G>T, c.409G>A, c.455T>C, c.958G>A, c.1000C>T and c.1154G>A). Furthermore, sequence analysis of the short-chain acyl-CoA dehydrogenase (SCAD) gene revealed heterozygosity for the prevalent c.625G>A susceptibility variation in all newborns and in the first reported IBD patient. Functional studies in isolated mitochondria demonstrated that the IBD variations present in the Danish newborn (c.409G>A and c.958G>A) together with a previously published IBD variation (c.905G>A) disturbed protein folding and reduced the levels of correctly folded IBD tetramers. Accordingly, low/no IBD residual enzyme activity was detectable when the variant IBD proteins were overexpressed in Chang cells.

Preventing birth defects with folic acid

There a few birth defects known to be preventable, but neural tube defects (NTDs) are one group of congenital anomalies that can potentially be prevented. When 400 micrograms of maternal periconceptional folic acid is taken daily, it can prevent many neural tube-related birth defects and thus reduce morbidity and mortality due to these birth defects. Health care providers should encourage every woman of reproductive age to consume 400 micrograms of synthetic folic acid daily, not just those who are planning a pregnancy. Supplementation needs to be started prior to conception for optimal effectiveness.