PCSK5 mutation in a patient with the VACTERL association

Wandering Spleen in a Patient With Significant Medical History

The clinical presentation of a wandering spleen is characterized mainly by unspecific acute symptoms, ranging from diffuse abdominal pain to left upper/lower quadrant and referred shoulder pain to asymptomatic. This has challenged accelerated medical care and impeded the acquisition of confirmatory diagnosis; therefore, increasing morbidity and mortality risks. Splenectomy is an established operative procedure for a wandering spleen. However, there has not been enough literature emphasizing the clinical history of congenital malformations and surgical corrections as inferential tools for facilitating a decisive and informed procedure. The case presented is of a 22-year-old female who reported to the emergency department with a five-day persistent left upper quadrant and left lower quadrant (LLQ) abdominal pain, associated with nausea. According to the medical history, the patient had a significant history of vertebral defects, anal atresia, cardiac anomalies, tracheoesophageal fistula, renal anomalies, and limb abnormalities (VACTERL) associated with congenital anomalies. By the age of eight years, the patient had undergone multiple surgical interventions, including tetralogy of Fallot repair, an imperforate anal repair with rectal pull-through, Malone antegrade continence enema (MACE), and bowel vaginoplasty. Computed tomography imaging of the abdomen revealed evidence of a wandering spleen in the LLQ with associated torsion of the splenic vasculature (whirl sign). Intra-operatively, appendicostomy was identified extending from the cecum in a near mid-line position, to the umbilicus, and carefully incised distally, preventing injury to the appendicostomy. The spleen was identified in the pelvis, and the individual vessels were clamped, divided, and ligated. Blood loss was minimal with no post-operative complications. This rare case report adds valuable teaching points about the treatment of wandering spleen in individuals with VACTERL anomalies.

Genetic Counseling and Diagnostics in Anorectal Malformation

Anorectal malformation (ARM) is a relatively frequently occurring congenital anomaly of hindgut development with a prevalence of 1 in 3,000 live births. ARM may present as an isolated anomaly, but it can also be associated with other anomalies, sometimes as part of a recognizable syndrome. After birth, much medical attention is given to the treatment and restoring of bowel function in children with ARM. Effort should also be given to studying the etiology of the ARM in these patients. This information is important to both the medical community and the family, because it can help guide treatment and provides information on the long-term prognosis of the patient and recurrence risk in the family.In this article, we will review the current knowledge on the (genetic) etiology of (syndromic) ARM and provide guidelines for (family) history taking and clinical and genetic studies of ARM patients and their families, which is needed to study the causal factors in an ARM patient and for genetic counseling of the families.

Renal agenesis-related genes are associated with Herlyn-Werner-Wunderlich syndrome

OBJECTIVE

To explore the genetic causes of Herlyn-Werner-Wunderlich syndrome (HWWS) using whole-exome sequencing.

DESIGN

Retrospective genetic study.

SETTING

Academic medical center.

PATIENT(S)

Twelve patients with HWWS.

INTERVENTION(S)

Whole-exome sequencing was performed for each patient. Sanger sequencing was used to confirm the potential causative genetic variants. In silico analysis and American College of Medical Genetics and Genomics guidelines were used to classify the pathogenicity of each variant.

MAIN OUTCOME MEASURE(S)

Rare sequence variants associated with müllerian duct development and renal agenesis were identified and included in subsequent analyses.

RESULT(S)

A total of 11 variants were identified in 10 of 12 patients (83.3%) and were considered to constitute a molecular genetic diagnosis of HWWS. These 11 variants were related to 9 genes: CHD1L, TRIM32, TGFBR3, WNT4, RET, FRAS1, FAT1, FOXF1, and PCSK5. All variants were heterozygous and confirmed by Sanger sequencing. The changes included one frameshift variant, one splice-site variant, and eight missense variants. All of the identified variants were absent or rare in Genome Aggregation Database East Asian populations. One of the 11 variants (9.1%) was classified as a pathogenic variant according to the American College of Medical Genetics and Genomics guidelines, and 8 of the 11 variants (72.7%) were classified as variants of uncertain significance.

CONCLUSION(S)

To our knowledge, this is the first report of the genetic causes of HWWS. Renal agenesis-related genes, such as CHD1L, TRIM32, RET, and WNT4, may be associated with HWWS. Identification of these variants can not only help us understand the etiology of HWWS and the relationship between reproductive tract development and urinary system development, but additionally improve the level of genetic counseling for HWWS.

Mouse Models of Human Proprotein Convertase Insufficiency

The kexin-like proprotein convertases perform the initial proteolytic cleavages that ultimately generate a variety of different mature peptide and proteins, ranging from brain neuropeptides to endocrine peptide hormones, to structural proteins, among others. In this review, we present a general introduction to proprotein convertase structure and biochemistry, followed by a comprehensive discussion of each member of the kexin-like subfamily of proprotein convertases. We summarize current knowledge of human proprotein convertase insufficiency syndromes, including genome-wide analyses of convertase polymorphisms, and compare these to convertase null and mutant mouse models. These mouse models have illuminated our understanding of the roles specific convertases play in human disease and have led to the identification of convertase-specific substrates; for example, the identification of procorin as a specific PACE4 substrate in the heart. We also discuss the limitations of mouse null models in interpreting human disease, such as differential precursor cleavage due to species-specific sequence differences, and the challenges presented by functional redundancy among convertases in attempting to assign specific cleavages and/or physiological roles. However, in most cases, knockout mouse models have added substantively both to our knowledge of diseases caused by human proprotein convertase insufficiency and to our appreciation of their normal physiological roles, as clearly seen in the case of the furin, proprotein convertase 1/3, and proprotein convertase 5/6 mouse models. The creation of more sophisticated mouse models with tissue- or temporally-restricted expression of specific convertases will improve our understanding of human proprotein convertase insufficiency and potentially provide support for the emerging concept of therapeutic inhibition of convertases.

Prenatal diagnosis and molecular cytogenetic characterization of three chromosomal abnormalities with favorable outcomes

OBJECTIVE

Here we present three cases of chromosomal abnormalities with favorable outcomes.

CASE REPORT

In Case 1, conventional karyotyping revealed a karyotype of 46, XY,t(7; 14) (q35; q13)[4]/46,XY[26]. Array comparative genomic hybridization (aCGH) analysis revealed no genomic imbalance. In Case 2, conventional karyotyping revealed a norma karyotype but aCGH analysis revealed a 3.2M chromosomal duplication (13q12.11q12.12(22, 073, 046_25, 230, 759)x3). In Case 3, aCGH analysis revealed a 5.5M chromosomal deletion (9q21.13q21.32 (78, 645, 382_84, 115, 555) x1). In all three cases, ultrasound examination showed no dysmorphisms and intrauterine growth restrictions (IUGRs) in the fetus. All three pregnancies resulted in phenotypically normal babies.

CONCLUSION

Chromosomal abnormalities may be associated with favorable outcomes. Combining conventional karyotyping, aCGH analysis and ultrasound results can provide a more accurate risk assessment for pregnant women with advanced age.

A Genetics-First Approach Revealed Monogenic Disorders in Patients With ARM and VACTERL Anomalies

Background: The VATER/VACTERL association (VACTERL) is defined as the non-random occurrence of the following congenital anomalies: Vertebral, Anal, Cardiac, Tracheal-Esophageal, Renal, and Limb anomalies. As no unequivocal candidate gene has been identified yet, patients are diagnosed phenotypically. The aims of this study were to identify patients with monogenic disorders using a genetics-first approach, and to study whether variants in candidate genes are involved in the etiology of VACTERL or the individual features of VACTERL: Anorectal malformation (ARM) or esophageal atresia with or without trachea-esophageal fistula (EA/TEF). Methods: Using molecular inversion probes, a candidate gene panel of 56 genes was sequenced in three patient groups: VACTERL (n = 211), ARM (n = 204), and EA/TEF (n = 95). Loss-of-function (LoF) and additional likely pathogenic missense variants, were prioritized and validated using Sanger sequencing. Validated variants were tested for segregation and patients were clinically re-evaluated. Results: In 7 out of the 510 patients (1.4%), pathogenic or likely pathogenic variants were identified in SALL1, SALL4, and MID1, genes that are associated with Townes-Brocks, Duane-radial-ray, and Opitz-G/BBB syndrome. These syndromes always include ARM or EA/TEF, in combination with at least two other VACTERL features. We did not identify LoF variants in the remaining candidate genes. Conclusions: None of the other candidate genes were identified as novel unequivocal disease genes for VACTERL. However, a genetics-first approach allowed refinement of the clinical diagnosis in seven patients, in whom an alternative molecular-based diagnosis was found with important implications for the counseling of the families.

Clinical Characteristics, Phenotype of Lipodystrophy and a Genetic Analysis of Six Diabetic Japanese Women with Familial Partial Lipodystrophy in a Diabetic Outpatient Clinic

Objective Our aim was to examine the clinical characteristics and phenotype of lipodystrophy of six diabetic Japanese women with partial lipodystrophy (PL) who received a genetic analysis at a diabetic outpatient clinic. Methods We screened for PL using dual energy X-ray absorptiometry (DEXA) and magnetic resonance imaging (MRI) among patients who had a reduced peripheral skinfold thickness at the diabetic outpatient clinic of Kusatsu General Hospital between August 2003 and August 2013. We performed a mutation analysis of candidate genes, including LMNA and PPARG, in two patients with PL and whole-exome sequencing in four patients with PL. Results We identified 15 patients with PL and performed a genetic analysis in 6 of them. They had no mutations in candidate genes known to be associated with familial partial lipodystrophy (FPLD). They all had near-complete loss of subcutaneous fat, particularly in the antero-lateral and posterior thigh region and the calf region. As almost all patients were characterized by fat loss in the lower limbs with abdominal fat accumulation, a high rate of positivity for a family history, diabetes, and an unknown genetic cause, we suspected they might have FPLD1. Some patients have shown relatively severe insulin resistance, while others have shown insulin deficiency. Four and one had severe atherosclerosis and liver cirrhosis, probably due to nonalcoholic steatohepatitis, respectively. Conclusion Almost all patients with PL identified in a diabetic outpatient clinic had subcutaneous fat loss in the lower limbs with excess truncal fat and might have had FPLD1.

Pcsk5 is required in the early cranio-cardiac mesoderm for heart development

Background

Loss of proprotein convertase subtilisin/kexin type 5 (Pcsk5) results in multiple developmental anomalies including cardiac malformations, caudal regression, pre-sacral mass, renal agenesis, anteroposterior patterning defects, and tracheo-oesophageal and anorectal malformations, and is a model for VACTERL/caudal regression/Currarino syndromes (VACTERL association - Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula and/or Esophageal atresia, Renal & Radial anomalies and Limb defects).

Results

Using magnetic resonance imaging (MRI), we examined heart development in mouse embryos with zygotic and cardiac specific deletion of Pcsk5. We show that conditional deletion of Pcsk5 in all epiblastic lineages recapitulates all developmental malformations except for tracheo-esophageal malformations. Using a conditional deletion strategy, we find that there is an essential and specific requirement for Pcsk5 in the cranio-cardiac mesoderm for cardiogenesis, but not for conotruncal septation or any other aspect of embryonic development. Surprisingly, deletion of Pcsk5 in cardiogenic or pharyngeal mesodermal progenitors that form later from the cranio-cardiac mesoderm does not affect heart development. Neither is Pcsk5 essential in the neural crest, which drives conotruncal septation.

Conclusions

Our results suggest that Pcsk5 may have an essential and early role in the cranio-cardiac mesoderm for heart development. Alternatively, it is possible that Pcsk5 may still play a critical role in Nkx2.5-expressing cardiac progenitors, with persistence of mRNA or protein accounting for the lack of effect of deletion on heart development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12861-017-0148-y) contains supplementary material, which is available to authorized users.

Underlying genetic factors of the VATER/VACTERL association with special emphasis on the "Renal" phenotype

The acronym VATER/VACTERL association (OMIM #192350) refers to the rare non-random co-occurrence of the following component features (CFs): vertebral defects (V), anorectal malformations (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb defects (L). According to epidemiological studies, the majority of patients with VATER/VACTERL association present with a "Renal" phenotype comprising a large spectrum of congenital renal anomalies. This finding is supported by evidence linking all of the human disease genes for the VATER/VACTERL association identified to date, namely, FGF8, FOXF1, HOXD13, LPP, TRAP1, and ZIC3, with renal malformations. Here we review these genotype-phenotype correlations and suggest that the elucidation of the genetic causes of the VATER/VACTERL association will ultimately provide insights into the genetic causes of the complete spectrum of congenital renal anomalies per se.

The genetic landscape and clinical implications of vertebral anomalies in VACTERL association

VACTERL association is a condition comprising multisystem congenital malformations, causing severe physical disability in affected individuals. It is typically defined by the concurrence of at least three of the following component features: vertebral anomalies (V), anal atresia (A), cardiac malformations (C), tracheo-oesophageal fistula (TE), renal dysplasia (R) and limb abnormalities (L). Vertebral anomaly is one of the most important and common defects that has been reported in approximately 60–95% of all VACTERL patients. Recent breakthroughs have suggested that genetic factors play an important role in VACTERL association, especially in those with vertebral phenotypes. In this review, we summarised the genetic studies of the VACTERL association, especially focusing on the genetic aetiology of patients with vertebral anomalies. Furthermore, genetic reports of other syndromes with vertebral phenotypes overlapping with VACTERL association are also included. We aim to provide a further understanding of the genetic aetiology and a better evidence for genetic diagnosis of the association and vertebral anomalies.

VATER/VACTERL Association and Caudal Regression with Xq25-q27.3 Microdeletion: A Case Report

We report a term female neonate with vertebral anomalies, anal and urethral atresia, esophageal atresia with tracheoesophageal fistula (TEF), renal agenesis, pulmonary hypoplasia, genital and sacral appendages, and a single umbilical artery. Genetic studies revealed a 20.91 Mb interstitial deletion of the long arm of X chromosome: Xq25-q27.3. This is a new case of VATER/VACTERL association with Xq25 microdeletion.