Developmental basis of trachea-esophageal birth defects.

Trachea-esophageal defects (TEDs), including esophageal atresia (EA), tracheoesophageal fistula (TEF), and laryngeal-tracheoesophageal clefts (LTEC), are a spectrum of life-threatening congenital anomalies in which the trachea and esophagus do not form properly. Up until recently, the developmental basis of these conditions and how the trachea and esophagus arise from a common fetal foregut was poorly understood. However, with significant advances in human genetics, organoids, and animal models, and integrating single cell genomics with high resolution imaging, we are revealing the molecular and cellular mechanisms that orchestrate tracheoesophageal morphogenesis and how disruption in these processes leads to birth defects. Here we review the current understanding of the genetic and developmental basis of TEDs. We suggest future opportunities for integrating developmental mechanisms elucidated from animals and organoids with human genetics and clinical data to gain insight into the genotype-phenotype basis of these heterogeneous birth defects. Finally, we envision how this will enhance diagnosis, improve treatment, and perhaps one day, lead to new tissue replacement therapy.

Presacral neuroendocrine tumors associated with the Currarino syndrome.

Currarino syndrome (CS) is an autosomal dominant syndrome caused by mutations in MNX1 and characterized by anorectal abnormalities, partial sacral agenesis, and presacral masses. The presacral masses are typically benign; however, malignant degeneration can occur, and presacral neuroendocrine tumors (NETs) have been reported in six cases. We report three individuals from two families affected by CS in which multiple individuals developed presacral NETs. The first family, 491, had six members with features of CS, including two siblings who presented with presacral, Grade 2 NETs, one of which had metastasized to bone and lymph nodes. A germline c.874C>T (p.Arg292Trp) mutation was found in a highly conserved region of MNX1 in three affected members who underwent sequencing. A second somatic variant/deletion in MNX1 was not detected in either patient's tumor. In the second family, 342, the proband presented with an incidentally discovered presacral NET. The proband's father had previously undergone resection of a presacral NET, and so genetic testing was performed, which did not reveal an MNX1 mutation or copy number variants. The lack of a second, somatic mutation in the tumors from family 491 argues against MNX1 acting as a tumor suppressor, and the absence of a germline MNX1 mutation in family 342 suggests that other genetic and anatomic factors contribute to the development of presacral NETs. These cases highlight the variable presentation of CS, and the potential for malignancy in these patients.

Comprehensive review of the duplication 3q syndrome and report of a patient with Currarino syndrome and de novo duplication 3q26.32-q27.2.

Partial duplications of the long arm of chromosome 3, dup(3q), are a rare but well-described condition, sharing features of Cornelia de Lange syndrome. Around two thirds of cases are derived from unbalanced translocations, whereas pure dup(3q) have rarely been reported. Here, we provide an extensive review of the literature on dup(3q). This search revealed several patients with caudal malformations and anomalies, suggesting that caudal malformations or anomalies represent an inherent phenotypic feature of dup(3q). In this context, we report a patient with a pure de novo duplication 3q26.32-q27.2. The patient had the clinical diagnosis of Currarino syndrome (CS) (characterized by the triad of sacral anomalies, anorectal malformations and a presacral mass) and additional features, frequently detected in patients with a dup(3q). Mutations within the MNX1 gene were found to be causative in CS but no MNX1 mutation could be detected in our patient. Our comprehensive search for candidate genes located in the critical region of the duplication 3q syndrome, 3q26.3-q27, revealed a so far neglected phenotypic overlap of dup(3q) and the Pierpont syndrome, associated with a mutation of the TBL1XR1 gene on 3q26.32.

HLX is a candidate gene for a pattern of anomalies associated with congenital diaphragmatic hernia, short bowel, and asplenia.

Isolated congenital diaphragmatic hernia is often a sporadic event with a low recurrence risk. However, underlying genetic etiologies, such as chromosome anomalies or single gene disorders, are identified in a small number of individuals. We describe two fetuses with a unique pattern of multiple congenital anomalies, including diaphragmatic hernia, short bowel and asplenia, born to first-cousin parents. Whole exome sequencing showed that both were homozygous for a missense variant, c.950A>C, predicting p.Asp317Ala, in the H.20-Like Homeobox 1 (HLX1) gene. HLX is a homeobox transcription factor gene which is relatively conserved across species. Hlx homozygous null mice have a short bowel and reduced muscle cells in the diaphragm, closely resembling the anomalies in the two fetuses and we therefore suggest that the HLX mutation in this family could explain the fetal findings.

Phenotype analysis impacts testing strategy in patients with Currarino syndrome.

Currarino syndrome (OMIM 175450) presents with sacral, anorectal, and intraspinal anomalies and presacral meningocele or teratoma. Autosomal dominant loss-of-function mutations in the MNX1 gene cause nearly all familial and 30% of sporadic cases. Less frequently, a complex phenotype of Currarino syndrome can be caused by microdeletions of 7q containing MNX1. Here, we report one familial and three sporadic cases of Currarino syndrome. To determine the most efficient genetic testing approach for these patients, we have compared results from MNX1 sequencing, chromosomal microarray, and performed a literature search with analysis of genotype-phenotype correlation. Based on the relationship between the type of mutation (intragenic MNX1 mutations vs 7q microdeletion) and the presence of intellectual disability, growth retardation, facial dysmorphism, and associated malformations, we propose a testing algorithm. Patients with the classic Currarino triad of malformations but normal growth, intellect, and facial appearance should have MNX1 sequencing first, and only in the event of a normal result should the clinician proceed with chromosomal microarray testing. In contrast, if growth delay and/or facial dysmorphy and/or intellectual disability are present, chromosomal microarray should be the first method of choice for genetic testing.

Thinking of VACTERL-H? Rule out Fanconi Anemia according to PHENOS.

VACTERL-H association includes three of eight features: vertebral anomalies, anal atresia, congenital heart disease, tracheo-esophageal fistula, esophageal atresia, renal, limb anomalies, and hydrocephalus. The VACTERL-H phenotype among cases with FA is considered to be about 5%; the frequency of FA among patients with VACTERL-H is unknown. We examined 54 patients with FA in the National Cancer Institute Inherited Bone Marrow Failure Syndrome Cohort for features of VACTERL-H, including imaging studies (radiology and ultrasound). Eighteen of the fifty-four patients had three or more VACTERL-H features. The presence of VACTERL-H association in 33% of those with FA is much higher than the previous estimate of 5% (P < 0.0001). We created the acronym PHENOS (Pigmentation, small Head, small Eyes, central Nervous system (not hydrocephalus), Otology, and Short stature) which includes all major phenotypic features of FA that are not in VACTERL-H; these findings were more frequent in the patients with FA who had VACTERL-H. Identification of any components of the VACTERL-H association should lead to imaging studies, and to consideration of the diagnosis of FA, particularly if the patient has radial ray and renal anomalies, as well as many features of PHENOS. There was no association of the presence or absence of VACTERL-H with development of cancer, stem cell transplant, or survival. Early diagnosis will lead to genetic counseling and early surveillance and management of complications of FA. © 2016 Wiley Periodicals, Inc.

46,XY disorders of sex development and congenital diaphragmatic hernia: a case with dysmorphic facies, truncus arteriosus, bifid thymus, gut malrotation, rhizomelia, and adactyly.

The association of 46,XY disorder of sex development (DSD) with congenital diaphragmatic hernia (CDH) is rare, but has been previously described with and without other congenital anomalies. Literature review identified five cases of 46,XY DSD associated with CDH and other congenital anomalies. These five cases share characteristics including CDH, 46,XY karyotype with external female appearing or ambiguous genitalia, cardiac anomalies, and decreased life span. The present case had novel features including truncus arteriosus, bifid thymus, gut malrotation, and limb anomalies consisting of rhizomelia and adactyly. With this case report, we present a review of the literature of cases of 46,XY DSD and CDH in association with multiple congenital abnormalities. This case may represent a unique syndrome of 46,XY DSD and diaphragmatic hernia or a more severe presentation of a syndrome represented in the previously reported cases.

A novel mutation in GATA6 causes pancreatic agenesis.

Heterozygous mutations in GATA6 have been linked to pancreatic agenesis and cardiac malformations. The aim of this study was to describe a new mutation in GATA6 in an infant with pancreatic agenesis, associated with truncus arteriosus and absent gallbladder. Clinical data were obtained from chart review. Gene sequencing was performed on genomic DNA. The patient was a female infant diagnosed shortly after birth with a severe cardiac malformation, absent gallbladder, anomalous hepatic blood flow, unilateral hydronephrosis and hydroureter, neonatal diabetes, and pancreatic exocrine insufficiency. Despite prolonged intensive management care, she died at 3 months of age because of cardiac complications. Analysis of her genomic DNA revealed a novel missense mutation of GATA6. The novel mutation described in this case extends the list of GATA6 mutations causing pancreatic agenesis and cardiac malformations.

In vivo knockdown of Brachyury results in skeletal defects and urorectal malformations resembling caudal regression syndrome.

The T-box transcription factor BRACHYURY (T) is a key regulator of mesoderm formation during early development. Complete loss of T has been shown to lead to embryonic lethality around E10.0. Here we characterize an inducible miRNA-based in vivo knockdown mouse model of T, termed KD3-T, which exhibits a hypomorphic phenotype. KD3-T embryos display axial skeletal defects caused by apoptosis of paraxial mesoderm, which is accompanied by urorectal malformations resembling the murine uro-recto-caudal syndrome and human caudal regression syndrome phenotypes. We show that there is a reduction of T in the notochord of KD3-T embryos which results in impaired notochord differentiation and its subsequent loss, whereas levels of T in the tailbud are sufficient for axis extension and patterning. Furthermore, the notochord in KD3-T embryos adopts a neural character and loses its ability to act as a signaling center. Since KD3-T animals survive until birth, they are useful for examining later roles for T in the development of urorectal tissues.

ACTA2 mutation with childhood cardiovascular, autonomic and brain anomalies and severe outcome.

Thoracic aortic aneurysm and dissection (TAAD) are associated with connective tissue disorders like Marfan syndrome and Loeys-Dietz syndrome, caused by mutations in the fibrillin-1, the TGFß-receptor 1- and -2 genes, the SMAD3 and TGFß2 genes, but have also been ascribed to ACTA2 gene mutations in adults, spread throughout the gene. We report on a novel de novo c.535C>T in exon 6 leading to p.R179C aminoacid substitution in ACTA2 in a toddler girl with primary pulmonary hypertension, persistent ductus arteriosus, extensive cerebral white matter lesions, fixed dilated pupils, intestinal malrotation, and hypotonic bladder. Recently, de novo ACTA2 R179H substitutions have been associated with a similar phenotype and additional cerebral developmental defects including underdeveloped corpus callosum and vermis hypoplasia in a single patient. The patient here shows previously undescribed abnormal lobulation of the frontal lobes and position of the gyrus cinguli and rostral dysplasis of the corpus callosum; she died at the age of 3 years during surgery due to vascular fragility and rupture of the ductus arteriosus. Altogether these observations support a role of ACTA2 in brain development, especially related to the arginine at position 179. Although all previously reported patients with R179H substitution successfully underwent the same surgery at younger ages, the severe outcome of our patient warns against the devastating effects of the R179C substitution on vasculature.

Presentation of incomplete Currarino triad in a 12-day-old patient with vomiting: a case report.

The complete Currarino triad (or syndrome) consists of anorectal anomalies, a sacral bony defect, and a presacral mass. Generally autosomal dominant in its inheritance, incomplete penetrance also characterizes this syndrome. We report the case of a 12-day-old patient with vomiting in whom a diagnosis of incomplete Currarino syndrome was made.

Currarino syndrome at Rikshospitalet 1961-2012.

BACKGROUND: Currarino syndrome is a rare hereditary condition with constipation as the main symptom. The typical patient has a combination of sacral, anorectal, intraspinal and presacral anomalies. Familial cases most often have a mutation in the MNX1 gene. The majority of Norwegian Currarino patients are treated at Rikshospitalet. This article gives an account of 50 years of experience with the condition. MATERIAL AND METHOD: The study is based on the medical records of patients with Currarino syndrome, as well as some first-degree relatives, from the period 1961-2012. We recorded the results of mutation analysis, X-ray of the sacrum, and ultrasound, MRI and/or CT scans, as well as the treatments administered. RESULTS: We treated 29 patients over the period in question, and in addition identified seven healthy relatives with a mutation in MNX1 and one relative with a pathognomonic sacral anomaly. There were 15 familial and 14 sporadic cases. Fourteen familial cases and one of the sporadic cases were shown to have a mutation in the MNX1 gene. Phenotypic variation was pronounced, and we saw no obvious correlation between genotype and phenotype. Twenty-six of the patients had constipation and 15 underwent a colostomy. Fourteen patients required neurosurgical and seven urogenital interventions. No patients had malignant disease. INTERPRETATION: Patients with Currarino syndrome have a highly variable clinical presentation with constipation as the main problem. In patients with a familial syndrome, a mutation in the MNX1 gene can be expected.

[Radiological findings in Currarino syndrome]. / Hallazgos radiológicos en el síndrome de Currarino.

OBJECTIVE: To describe the clinical, radiological and genetic findings of a family affected by Currarino syndrome (CS) (agenesis of the sacrum, presacral mass, and anal-rectal anomalies), and to familiarise the radiologist with this condition that, although uncommon, could be suspected by its characteristic images. MATERIAL AND METHODS: A study was made of 8 out of 9 family members (the parents, 7 siblings; 4 males and 3 females) suspected of having CS. The clinical and genetic findings are described. Using simple X-rays, ultrasound and magnetic resonance imaging, the presence of agenesis of the sacrum, a presacral mass and anal-rectal anomalies were investigated. Furthermore, a genetic analysis of the HLBX9 gene was performed. Permission by the Ethics Committee was not requested as all the family members gave their consent by signing a document. RESULTS: The mother with a scimitar-shaped sacrum confirmed that she was the transmitter of the genetic mutation. One of the seven siblings had complete CS (sacral agenesis, anorectal stenosis, and anterior meningocele). Four siblings had an incomplete CS: 3 with sacral agenesis and a presacral mass (two anterior meningoceles and one teratoma) and the fourth with sacral agenesis and anorectal stenosis. One sibling had no anomalies. The mother, as well as four siblings, did not have the HLXB9 gene mutation. CONCLUSION: When there is sacral agenesis, the possibility of presacral masses and anorectal changes should be investigated. Likewise, if there is familial association, they should be investigated for a CS.

Loss of Sprouty2 partially rescues renal hypoplasia and stomach hypoganglionosis but not intestinal aganglionosis in Ret Y1062F mutant mice.

The glial cell line-derived neurotrophic factor (GDNF)/RET tyrosine kinase signaling pathway plays crucial roles in the development of the enteric nervous system (ENS) and the kidney. Tyrosine 1062 (Y1062) in RET is an autophosphorylation residue that is responsible for the activation of the PI3K/AKT and RAS/MAPK signaling pathways. Mice lacking signaling via Ret Y1062 show renal hypoplasia and hypoganglionosis of the ENS although the phenotype is milder than the Gdnf- or Ret-deficient mice. Sprouty2 (Spry2) was found to be an antagonist for fibroblast growth factor receptor (FGFR) and acts as an inhibitory regulator of ERK activation. Spry2-deficient mice exhibit hearing loss and enteric nerve hyperplasia. In the present study, we generated Spry2-deficient and Ret Y1062F knock-in (tyrosine 1062 is replaced with phenylalanine) double mutant mice to see if abnormalities of the ENS and kidney, caused by loss of signaling via Ret Y1062, are rescued by a deficiency of Spry2. Double mutant mice showed significant recovery of ureteric bud branching and ENS development in the stomach. These results indicate that Spry2 regulates downstream signaling mediated by GDNF/RET signaling complex in vivo.

Currarino syndrome with pelvic neuroendocrine tumor diagnosed by post-mortem genetic analysis of tissue specimens.

Currarino syndrome (CS) is an autosomal dominant disorder of embryonic development characterized by the triad of anorectal abnormalities, partial sacral agenesis, and presacral mass. Mutations of the HLXB9 gene have been identified in most CS cases, but a precise genotype-phenotype correlation has not been described so far. We report the clinical case of a 44-year-old Caucasian woman with malignant neuroendocrine transformation of a pre-sacrococcygeal mass combined with bicornuate uterus, dermoid cyst of the ovaries, and chronic constipation. After the patient died, a sacrococcygeal malformation and anterior meningocele were diagnosed in her 22-year-old son. CS diagnosis was then retrospectively confirmed by molecular analysis of normal and pathological tissue specimens of the mother, with identification of a HLXB9 mutation (c.727C>T; p.R243W). CS should be considered, and genetic counseling recommended, to all patients with presacral masses. Since malignant neuroendocrine transformation of presacral mass in CS is a possible complication, even thought rare, close follow up in these patients is advisable.

High incidence of PRSS1 and SPINK1 mutations in Korean children with acute recurrent and chronic pancreatitis.

OBJECTIVES: We evaluated the frequencies and clinical consequences of mutations in the genes encoding cationic trypsinogen, serine protease 1 (PRSS1), and serine protease inhibitor Kazal type 1 (SPINK1) in children with acute recurrent pancreatitis (ARP) and chronic pancreatitis (CP). PATIENTS AND METHODS: The study population consisted of 32 children with ARP or CP and 28 healthy controls. We analyzed clinical data and the sequences of the entire coding region and the intron-exon boundaries of the PRSS1 and SPINK1 genes from each patient. RESULTS: Fifteen (46.9%) of the 32 patients had at least 1 PRSS1 or SPINK1 mutation. Four (12.5%) of the 32 patients carried the p.N29I, p.R122H, or p.N29T mutation or a p.G208A variant of the PRSS1 gene in a heterozygote state. Eleven (34.4%) of the 32 patients carried either the IVS3 + 2T>C or p.N34S mutation of the SPINK1 gene. No PRSS1 or SPINK1 mutations were identified in the control group. In particular, mutations were identified in 4 of our patients who experienced pancreas divisum with CP, whereas the remaining 2 patients with pancreas divisum and ARP did not have mutation. CONCLUSIONS: The frequencies of the PRSS1 and SPINK1 mutations are relatively high in Korean children with ARP or CP. Mutations in the PRSS1 and SPINK1 genes are highly associated with the development of childhood ARP or CP. Our findings suggest that patients with genetic mutations combined with pancreas divisum tend to develop CP early.

[Intestinal malrotation: genetics features and other congenital malformations in children].

The article is devoted to features of prenatal development of children with intestinal malrotation. Mass, height, head and chest circumferences of children after birth have been studied. In addition all associated malformations, a blood group (ABO system) and the rhesus-factor have been investigated. In comparison to the control group of newborn the disorders of prenatal development have included associated malformations, low anthropometric data after birth, decreasing of pA gene frequency. Notable, children with intestinal malrotation have had high frequency of malformations as in the abdominal and thoracic cavities as outside intestinal innervations: the small pelvis, the facial skeleton, the upper and lower extremity.

Currarino syndrome: a comprehensive genetic review of a rare congenital disorder.

BACKGROUND: The triad of a presacral mass, sacral agenesis and an anorectal anomaly constitutes the rare Currarino syndrome (CS), which is caused by dorsal-ventral patterning defects during embryonic development. The major causative CS gene is MNX1, encoding a homeobox protein. MAIN BODY: In the majority of patients, CS occurs as an autosomal dominant trait; however, a female predominance observed, implies that CS may underlie an additional mode(s) of inheritance. Often, the diagnosis of CS is established solely by clinical findings, impacting a detailed analysis of the disease. Our combined data, evaluating more than 60 studies reporting patients with CS-associated mutations, revealed a slightly higher incidence rate in females with a female-to-male ratio of 1.39:1. Overall, MNX1 mutation analysis was successful in only 57.4% of all CS patients investigated, with no mutation detected in 7.7% of the familial and 68% of the sporadic patients. Our studies failed to detect the presence of an expressed MNX1 isoform that might explain at least some of these mutation-negative cases. CONCLUSION: Aside from MNX1, other genes or regulatory regions may contribute to CS and we discuss several cytogenetic studies and whole-exome sequencing data that have implicated further loci/genes in its etiology.