Raised risk of Wilms tumour in patients with aniridia and submicroscopic WT1 deletion

Bilateral Peters' anomaly, aniridia and Wilms tumour (WAGR syndrome) in monozygotic twins

AIM

This study reports the bilateral association of Peters' anomaly and congenital aniridia in monozygotic twins subsequently diagnosed with Wilms tumour (WAGR syndrome).

METHODS

Two monozygotic female twins were referred at age 2 months with bilateral corneal opacity. A diagnosis of Peters' anomaly associated to aniridia was made in both eyes of both twins. Physical examination and ultrasonography were carried out at 12 months of age to explore the possibility of WAGR-related anomalies, specifically Wilms tumour. DNA were isolated and subjected to whole exome sequencing.

RESULTS

Peters' anomaly associated to aniridia in both eyes as well as bilateral Wilms tumour in both children were diagnosed. Exome analyses showed a large heterozygous deletion encompassing 6 648 473 bp in chromosome 11p13, using Integrative Genomics Viewer and AnnotSV software.

CONCLUSION

WAGR syndrome is a rare contiguous gene deletion syndrome with a greater risk of developing Wilms tumour associated with Peters' anomaly and congenital aniridia. However, co-occurrence of both anomalies was rarely reported in twins, and never in both eyes of monozygotic twins. Here, we report the bilateral association of Peters' anomaly and congenital aniridia in monozygotic twins with WAGR syndrome.

Pediatric renal tumor epidemiology: Global perspectives, progress, and challenges

Pediatric renal tumors account for 3%-11% of childhood cancers, the most common of which is Wilms tumor or nephroblastoma. Epidemiology plays a key role in cancer prevention and control by describing the distribution of cancer and discovering risk factors for cancer. Large pediatric research consortium trials have led to a clearer understanding of pediatric renal tumors, identification of risk factors, and development of more risk-adapted therapies. These therapies have improved event-free and overall survival for children. However, several challenges remain and not all children have benefited from the improved outcomes. In this article, we review the global epidemiology of pediatric renal tumors, including key consortium and global studies. We identify current knowledge gaps and challenges facing both high and low middle-incomes countries.

Pediatric renal tumor epidemiology: Global perspectives, progress, and challenges

Pediatric renal tumors account for 3%-11% of childhood cancers, the most common of which is Wilms tumor or nephroblastoma. Epidemiology plays a key role in cancer prevention and control by describing the distribution of cancer and discovering risk factors for cancer. Large pediatric research consortium trials have led to a clearer understanding of pediatric renal tumors, identification of risk factors, and development of more risk-adapted therapies. These therapies have improved event-free and overall survival for children. However, several challenges remain and not all children have benefited from the improved outcomes. In this article, we review the global epidemiology of pediatric renal tumors, including key consortium and global studies. We identify current knowledge gaps and challenges facing both high and low middle-incomes countries.

[Tumor predisposition syndromes and nephroblastoma : Early diagnosis with imaging]

CLINICAL/METHODICAL ISSUE

The Beckwith-Wiedemann spectrum (BWSp) as well as the WT1-related syndromes, Denys-Drash syndrome (DDS) and WAGR spectrum (Wilms tumor, Aniridia, genitourinary anomalies and a range of developmental delays) are tumor predisposition syndromes (TPS) of Wilms tumor (WT). Patients with associated TPS are at higher risk of developing chronic kidney disease and bilateral and metachronous tumors as well as nephrogenic rests.

STANDARD RADIOLOGICAL METHODS

Standard imaging diagnostics for WT include renal ultrasound and magnetic resonance imaging (MRI). In the current renal tumor studies Umbrella SIOP-RTSG 2016 and Randomet 2017, thoracic computed tomography (CT) is also recommended as standard. Positron emission tomography (PET)-CT and whole-body MRI, on the other hand, are not part of routine diagnostics.

METHODOLOGICAL INNOVATIONS

In recent publications, renal ultrasound is recommended every 3 months until the age of 7 years in cases of clinical suspicion or molecularly proven TPS.

PERFORMANCE

Patients with TPS and regular renal ultrasounds have smaller tumor volumes and lower tumor stages at WT diagnosis than patients without such a screening. This allows a reduction of therapy intensity and facilitates the performance of nephron sparing surgery, which is prognostically relevant especially in bilateral WT.

ACHIEVEMENTS

Early diagnosis of WT in the context of TPS ensures the greatest possible preservation of healthy and functional renal tissue. Standardized screening by regular renal ultrasounds should therefore be firmly established in clinical practice.

PRACTICAL RECOMMENDATIONS

The initial diagnosis of TPS is clinical and requires a skilled and attentive examiner in the presence of sometimes subtle clinical manifestations, especially in the case of BWSp. Clinical diagnosis should be followed by genetic testing, which should then be followed by sonographic screening.

UroVysionTM Fluorescence In Situ Hybridization in Urological Cancers: A Narrative Review and Future Perspectives

UroVysionTM is a fluorescence in situ hybridization assay that was developed for the detection of bladder cancer (UC accounted for 90%) in urine specimens. It consists of fluorescently labeled DNA probes to the pericentromeric regions of chromosomes 3, 7, 17 and to the 9p21 band location of the P16 tumor suppressor gene, which was approved by the Food and Drug Administration (FDA) in 2001 and 2005, respectively, for urine detection in patients with suspected bladder cancer and postoperative recurrence monitoring. Furthermore, recent studies also demonstrated that U-FISH was useful for assessing superficial bladder cancer patients' response to Bacillus Calmette-Guérin therapy and in detecting upper tract urothelial carcinoma. Therefore, positive U-FISH was well known to urologists as a molecular cytogenetic technique for the detection of UC. However, with the continuous enrichment of clinical studies at home and abroad, U-FISH has shown a broader application space in the detection of various urinary primary tumors and even metastatic tumors. This review focuses on summarizing the research status of U-FISH in UC, non-urothelial carcinoma and metastatic tumor, so as to strengthen urologists' more comprehensive understanding of the application value of U-FISH and better complete the accurate diagnosis and treatment of urological cancers.

Wilms tumour surveillance in at-risk children: Literature review and recommendations from the SIOP-Europe Host Genome Working Group and SIOP Renal Tumour Study Group

Since previous consensus-based Wilms tumour (WT) surveillance guidelines were published, novel genes and syndromes associated with WT risk have been identified, and diagnostic molecular tests for previously known syndromes have improved. In view of this, the International Society of Pediatric Oncology (SIOP)-Europe Host Genome Working Group and SIOP Renal Tumour Study Group hereby present updated WT surveillance guidelines after an extensive literature review and international consensus meetings. These guidelines are for use by clinical geneticists, pediatricians, pediatric oncologists and radiologists involved in the care of children at risk of WT. Additionally, we emphasise the need to register all patients with a cancer predisposition syndrome in national or international databases, to enable the development of better tumour risk estimates and tumour surveillance programs in the future.

Systemic diseases and the cornea

There is a number of systemic diseases affecting the cornea. These include endocrine disorders (diabetes, Graves' disease, Addison's disease, hyperparathyroidism), infections with viruses (SARS-CoV-2, herpes simplex, varicella zoster, HTLV-1, Epstein-Barr virus) and bacteria (tuberculosis, syphilis and Pseudomonas aeruginosa), autoimmune and inflammatory diseases (rheumatoid arthritis, Sjögren's syndrome, lupus erythematosus, gout, atopic and vernal keratoconjunctivitis, multiple sclerosis, granulomatosis with polyangiitis, sarcoidosis, Cogan's syndrome, immunobullous diseases), corneal deposit disorders (Wilson's disease, cystinosis, Fabry disease, Meretoja's syndrome, mucopolysaccharidosis, hyperlipoproteinemia), and genetic disorders (aniridia, Ehlers-Danlos syndromes, Marfan syndrome). Corneal manifestations often provide an insight to underlying systemic diseases and can act as the first indicator of an undiagnosed systemic condition. Routine eye exams can bring attention to potentially life-threatening illnesses. In this review, we provide a fairly detailed overview of the pathologic changes in the cornea described in various systemic diseases and also discuss underlying molecular mechanisms, as well as current and emerging treatments.

Clinical characteristics and outcomes of children with WAGR syndrome and Wilms tumor and/or nephroblastomatosis: The 30-year SIOP-RTSG experience

BACKGROUND

WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and range of developmental delays) is a rare contiguous gene deletion syndrome with a 45% to 60% risk of developing Wilms tumor (WT). Currently, surveillance and treatment recommendations are based on limited evidence.

METHODS

Clinical characteristics, treatments, and outcomes were analyzed for patients with WAGR and WT/nephroblastomatosis who were identified through International Society of Pediatric Oncology Renal Tumor Study Group (SIOP-RTSG) registries and the SIOP-RTSG network (1989-2019). Events were defined as relapse, metachronous tumors, or death.

RESULTS

Forty-three patients were identified. The median age at WT/nephroblastomatosis diagnosis was 22 months (range, 6-44 months). The overall stage was available for 40 patients, including 15 (37.5%) with bilateral disease and none with metastatic disease. Histology was available for 42 patients; 6 nephroblastomatosis without further WT and 36 WT, including 19 stromal WT (52.8%), 12 mixed WT (33.3%), 1 regressive WT (2.8%) and 2 other/indeterminable WT (5.6%). Blastemal type WT occurred in 2 patients (5.6%) after prolonged treatment for nephroblastomatosis; anaplasia was not reported. Nephrogenic rests were present in 78.9%. Among patients with WT, the 5-year event-free survival rate was 84.3% (95% confidence interval, 72.4%-98.1%), and the overall survival rate was 91.2% (95% confidence interval, 82.1%-100%). Events (n = 6) did not include relapse, but contralateral tumor development (n = 3) occurred up to 7 years after the initial diagnosis, and 3 deaths were related to hepatotoxicity (n = 2) and obstructive ileus (n = 1).

CONCLUSIONS

Patients with WAGR have a high rate of bilateral disease and no metastatic or anaplastic tumors. Although they can be treated according to existing WT protocols, intensive monitoring of toxicity and surveillance of the remaining kidney(s) are advised.

LAY SUMMARY

WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and range of developmental delays) is a rare genetic condition with an increased risk of developing Wilms tumor. In this study, 43 patients with WAGR and Wilms tumor (or Wilms tumor precursor lesions/nephroblastomatosis) were identified through the international registry of the International Society of Pediatric Oncology Renal Tumor Study Group (SIOP-RTSG) and the SIOP-RTSG network. In many patients (37.5%), both kidneys were affected. Disease spread to other organs (metastases) did not occur. Overall, this study demonstrates that patients with WAGR syndrome and Wilms tumor can be treated according to existing protocols. However, intensive monitoring of treatment complications and surveillance of the remaining kidney(s) are advised.

A rare case of an isolated PAX6 mutation, aniridia, and Wilms tumor

Introduction: Wilms tumor (WT) is the most common renal malignancy of children and can be seen in WAGR syndrome (WT, aniridia, genitourinary anomalies, and intellectual disability). WAGR results from a contiguous gene deletion within the 11p13 region, encompassing the WT1 gene, often responsible for WT development, and the PAX6 gene, responsible for aniridia. Aniridia, a pan-ocular disease resulting from iris hypoplasia, is thought to increase the risk for WT development if their genetic alteration spans both the WT1 and the PAX6 genes on 11p13.Case Description: We describe a unique case of a patient with aniridia secondary to a heterozygous PAX6 nonsense mutation who developed WT despite no additional identifiable germline genetic drivers for this disease.Discussion: Isolated mutations in PAX6 previously have not been associated with increased risk of WT development case raises the question of if surveillance for WT should be continued in patients with aniridia with an isolated PAX6 mutation identified.

The Challenges of Chromosome Y Analysis and the Implications for Chronic Kidney Disease

The role of chromosome Y in chronic kidney disease (CKD) remains unknown, as chromosome Y is typically excluded from genetic analysis in CKD. The complex, sex-specific presentation of CKD could be influenced by chromosome Y genetic variation, but there is limited published research available to confirm or reject this hypothesis. Although traditionally thought to be associated with male-specific disease, evidence linking chromosome Y genetic variation to common complex disorders highlights a potential gap in CKD research. Chromosome Y variation has been associated with cardiovascular disease, a condition closely linked to CKD and one with a very similar sexual dimorphism. Relatively few sources of genetic variation in chromosome Y have been examined in CKD. The association between chromosome Y aneuploidy and CKD has never been explored comprehensively, while analyses of microdeletions, copy number variation, and single-nucleotide polymorphisms in CKD have been largely limited to the autosomes or chromosome X. In many studies, it is unclear whether the analyses excluded chromosome Y or simply did not report negative results. Lack of imputation, poor cross-study comparability, and requirement for separate or additional analyses in comparison with autosomal chromosomes means that chromosome Y is under-investigated in the context of CKD. Limitations in genotyping arrays could be overcome through use of whole-chromosome sequencing of chromosome Y that may allow analysis of many different types of genetic variation across the chromosome to determine if chromosome Y genetic variation is associated with CKD.

Improving molecular diagnosis of aniridia and WAGR syndrome using customized targeted array-based CGH

Chromosomal deletions at 11p13 are a frequent cause of congenital Aniridia, a rare pan-ocular genetic disease, and of WAGR syndrome, accounting up to 30% of cases. First-tier genetic testing for newborn with aniridia, to detect 11p13 rearrangements, includes Multiplex Ligation-dependent Probe Amplification (MLPA) and karyotyping. However, neither of these approaches allow obtaining a complete picture of the high complexity of chromosomal deletions and breakpoints in aniridia. Here, we report the development and validation of a customized targeted array-based comparative genomic hybridization, so called WAGR-array, for comprehensive high-resolution analysis of CNV in the WAGR locus. Our approach increased the detection rate in a Spanish cohort of 38 patients with aniridia, WAGR syndrome and other related ocular malformations, allowing to characterize four undiagnosed aniridia cases, and to confirm MLPA findings in four additional patients. For all patients, breakpoints were accurately established and a contiguous deletion syndrome, involving a large number of genes, was identified in three patients. Moreover, we identified novel microdeletions affecting 3' PAX6 regulatory regions in three families with isolated aniridia. This tool represents a good strategy for the genetic diagnosis of aniridia and associated syndromes, allowing for a more accurate CNVs detection, as well as a better delineation of breakpoints. Our results underline the clinical importance of performing exhaustive and accurate analysis of chromosomal rearrangements for patients with aniridia, especially newborns and those without defects in PAX6 after diagnostic screening.

Glaucoma Genes and Mechanisms

Genetic studies have yielded important genes contributing to both early-onset and adult-onset forms of glaucoma. The proteins encoded by the current collection of glaucoma genes participate in a broad range of cellular processes and biological systems. Approximately half the glaucoma-related genes function in the extracellular matrix, however proteins involved in cytokine signaling, lipid metabolism, membrane biology, regulation of cell division, autophagy, and ocular development also contribute to the disease pathogenesis. While the function of these proteins in health and disease are not completely understood, recent studies are providing insight into underlying disease mechanisms, a critical step toward the development of gene-based therapies. In this review, genes known to cause early-onset glaucoma or contribute to adult-onset glaucoma are organized according to the cell processes or biological systems that are impacted by the function of the disease-related protein product.

A novel Alu-mediated microdeletion at 11p13 removes WT1 in a patient with cryptorchidism and azoospermia

This article describes a patient with cryptorchidism and nonobstructive azoospermia presenting a novel microdeletion of approximately 1 Mb at 11p13. It was confirmed by multiplex ligation-dependent probe amplification that this heterozygous deletion spanned nine genes (WT1, EIF3M, CCDC73, PRRG4, QSER1, DEPDC7, TCP11L1, CSTF3 and HIPK3) and positioned the breakpoints within highly homologous repetitive elements. As far as is known, this is the smallest deletion as-yet described encompassing the WT1 gene and was detected only once in a total of 32 Portuguese patients with isolated uni- or bilateral cryptorchidism. These findings suggest that molecular analysis in patients with genitourinary features suggestive of WT1 impairment, namely cryptorchidism and renal abnormalities, may reveal cryptic genetic defects.

[Minor phenotypic variants in patients with acute lymphoblastic leukemia from west Mexico]

INTRODUCTION

Acute lymphoblastic leukemia (ALL) has been associated with an excess of minor phenotypic variants (MPV), including common variants and minor anomalies, indicative of an altered phenogenesis. The objective of the study was to determine the association between MPV and ALL.

PATIENTS AND METHODS

In a hospital based case-control study, we studied 120 children with ALL (including standard and high risk) and 120 healthy children as a control group, matched for age and sex, seen in the Hospital Civil de Guadalajara Dr. Juan I. Menchaca (Guadalajara, Mexico). In both groups, 28 anthropometric measurements were made, as well as a systematic search for 405 MPV, through a physical examination. Adjusted odds ratio was estimated (aOR) with its intervening variables by logistic regression. The confidence interval was 95% (95%CI).

RESULTS

Anthropometric signs associated with ALL were: long upper segment (aOR= 2.19, 95%CI: 1.01-4.76), broad jaw (aOR= 2.62, 95%CI: 1.29-5.30), narrow ears (aOR= 6.22, 95%CI: 2.60-14.85), and increase in internipple distance (aOR= 2.53, 95%CI: 1.07-5.98). The hypoplasia mesofacial, broad forehead, small nose, short columella, narrow ears, telethelia, Sydney crease (SC), Greek type feet and café-au-lait spots (CALS), had a 3 to 17 times higher frequency in children with ALL. By number, an association was found from ≥4 MPV (aOR= 2.14, 95%CI: 1.25-3.66, P=.004).

CONCLUSIONS

From ≥4 MPV, an association was found with ALL, suggesting prenatal factors in phenogenesis and leukemogenesis. CALS and SC were confirmed as MPV in children with ALL.

Evaluation of chromosome 11p imbalances in aniridia and Wilms tumor patients

Newborn sporadic aniridia patients with an 11p13 deletion including the WT1 gene have an increased risk to develop Wilms tumor. At present a risk for Wilms tumor cannot be estimated in patients with deletions not extending into, but ending close to WT1. Therefore, it is important to determine the distance of deletion endpoints from the WT1 gene and survey these patients for a longer follow-up time to obtain a more defined risk estimation. Using molecular methods, such as Multiplex Ligation-dependent Probe Amplification (MLPA), deletion endpoints can be mapped more accurately than with FISH. We describe here the analysis of six aniridia patients, in two of these the deletions extend close to the 3' end of WT1. At the ages of 3.8 and 4 years they have not developed a Wilms tumor, suggesting a low tumor risk in such patients. In addition we have studied 24 non-AN cases with a higher likelihood for WT1 alterations with MLPA and found no deletions. In conclusion newborns with aniridia should be studied with molecular methods that can determine deletion endpoints in 11p13 exactly. For a better Wilms tumor risk estimation cases with deletion endpoints close to WT1 should be followed for at least 4-5 years. Furthermore germ line intragenic deletions affecting WT1 in patients with a higher likelihood for a WT1 association, for example, bilateral tumors, genitourinary aberrations, or nephrotic syndrome, were not found in this study, suggesting that deletions are rare events.

Pediatric urologic oncology

This article reviews common pediatric urologic cancers involving the genitourinary system. Rhabdomyosarcoma may occur in the bladder, prostate, paratesticular regions, vagina, or uterus. Some of these locations, such as the paratesticular region, have a more favorable outcome. Benign neoplasms account for the majority of pediatric testicular tumors and most are managed with testis-sparing surgery. Most genitourinary malignancies are expected to have a good outcome. One focus of treatment is organ preservation but not at the expense of a good oncologic outcome. Late sequelae of anticancer therapy are a concern and every attempt is made to decrease the intensity of tumor treatment.

Aniridia

Aniridia is a rare congenital disorder in which there is a variable degree of hypoplasia or the absence of iris tissue associated with multiple other ocular changes, some present from birth and some arising progressively over time. Most cases are associated with dominantly inherited mutations or deletions of the PAX6 gene. This article will review the clinical manifestations, the molecular basis including genotype-phenotype correlations, diagnostic approaches and management of aniridia.

Genetic and genomic analysis of classic aniridia in Saudi Arabia

PURPOSE

To determine the genetic and genomic alterations underlying classic aniridia in Saudi Arabia, a region with social preference for consanguineous marriage.

METHODS

Prospective study of consecutive patients referred to a pediatric ophthalmologist in Saudi Arabia (2005-2009). All patients had paired box gene 6 (PAX6) analysis (sequencing and multiplex ligation-dependent probe amplification analysis if sequencing was normal). If PAX6 analysis was negative, the following were performed: candidate gene sequencing (forkhead box C1 [FOXC1], paired-like homeodomain transcription factor 2 [PITX2], cytochrome P450, family 1, subfamily B [CYP1B1], paired-like homeodomain transcription factor 3 [PITX3], and v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog [MAF]) and molecular karyotyping by array competitive genomic hybridization (250K single nucleotide polymorphism (SNP) arrays).

RESULTS

All 12 probands (4 months-25 years of age; four boys and eight girls) had lens opacity and foveal hypoplasia in addition to no grossly visible iris. Four cases were familial. All cases were products of consanguineous unions except for three, one of which was endogamous. Heterozygous PAX6 mutations (including two novel mutations) were detectable in all but two cases, both of which were sporadic. In one of these two cases, the phenotype segregated with homozygosity for a previously-reported pathogenic missense FOXC1 variant (p.P297S) when homozygosity for chromosome 11q24.2 deletion (chr11:125,001,547-125,215,177 [rs114259885; rs112291840]) was also present. In the other, no genetic or genomic abnormalities were found.

CONCLUSIONS

The classic aniridia phenotype in Saudi Arabia is typically caused by heterozygous PAX6 mutations, even in the setting of enhanced homozygosity from recent shared parental ancestry. For PAX6-negative cases, interaction between missense variation in an anterior segment developmental gene and copy number variation elsewhere in the genome may be a potential mechanism for the phenotype.

Current management of wilms' tumor

Wilms' tumor is the most common malignant renal tumor in children. Survival has improved dramatically over time as a result of prospective randomized clinical trials conducted by the pediatric cooperative cancer groups. Current research is directed toward identifying low-risk patients for whom a reduction in treatment intensity would decrease long-term morbidity. This article reviews the most recent advances in the biology and treatment of children with Wilms' tumor.

Genetic analysis of chromosome 11p13 and the PAX6 gene in a series of 125 cases referred with aniridia

A series of 125 patients referred primarily with aniridia classified as either sporadic (74), familial (24), or in association with WAGR syndrome (14) or other malformations (13) was analysed for mutations, initially by karyotyping and targeted FISH analysis of chromosome 11p13. These methods identified mutations in a significant proportion of patients, 34/125 (27%). Two cases had chromosome rearrangements involving 11p13, 16 cases had visible deletions, and 16 cases had cryptic deletions identified by FISH. The frequency of cryptic deletions in familial aniridia was 27% and in sporadic isolated aniridia was 22%. Of the 14 cases referred with WAGR syndrome, 10 (71%) had chromosomal deletions, 2 cryptic and 8 visible. Of the 13 cases with aniridia and other malformations, 5 (38%) had a chromosomal rearrangement or deletion. In 37 cases with no karyotypic or cryptic chromosome abnormality, sequence analysis of the PAX6 gene was performed. Mutations were identified in 33 cases; 22 with sporadic aniridia, 10 with familial aniridia and 1 with aniridia and other non-WAGR syndrome associated anomalies. Overall, 67 of 71 cases (94%) undergoing full mutation analysis had a mutation in the PAX6 genomic region.

Pax6 3' deletion results in aniridia, autism and mental retardation

The PAX6 gene is a transcription factor expressed early in development, predominantly in the eye, brain and gut. It is well known that mutations in PAX6 may result in aniridia, Peter's anomaly and kertatisis. Here, we present mutation analysis of a patient with aniridia, autism and mental retardation. We identified and characterized a 1.3 Mb deletion that disrupts PAX6 transcriptional activity and deletes additional genes expressed in the brain. Our findings provide continued evidence for the role of PAX6 in neural phenotypes associated with aniridia.