MED12-Related (Neuro)Developmental Disorders: A Question of Causality.

MED12 is a member of the Mediator complex that is involved in the regulation of transcription. Missense variants in MED12 cause FG syndrome, Lujan-Fryns syndrome, and Ohdo syndrome, as well as non-syndromic intellectual disability (ID) in hemizygous males. Recently, female patients with de novo missense variants and de novo protein truncating variants in MED12 were described, resulting in a clinical spectrum centered around ID and Hardikar syndrome without ID. The missense variants are found throughout MED12, whether they are inherited in hemizygous males or de novo in females. They can result in syndromic or nonsyndromic ID. The de novo nonsense variants resulting in Hardikar syndrome that is characterized by facial clefting, pigmentary retinopathy, biliary anomalies, and intestinal malrotation, are found more N-terminally, whereas the more C-terminally positioned variants are de novo protein truncating variants that cause a severe, syndromic phenotype consisting of ID, facial dysmorphism, short stature, skeletal abnormalities, feeding difficulties, and variable other abnormalities. This broad range of distinct phenotypes calls for a method to distinguish between pathogenic and non-pathogenic variants in MED12. We propose an isogenic iNeuron model to establish the unique gene expression patterns that are associated with the specific MED12 variants. The discovery of these patterns would help in future diagnostics and determine the causality of the MED12 variants.

Gastrointestinal disorders in Down syndrome.

Down syndrome is the most common human chromosomal disorder. Among clinical findings, one constant concern is the high prevalence of gastrointestinal system alterations. The aim of this study was to determine the prevalence of gastrointestinal disorders at a Down syndrome outpatient clinic during a 10-year follow-up period. Data from medical files were retrospectively reviewed from 1,207 patients. Gastrointestinal changes occurred in 612 (50.7%). The most prevalent disorder was chronic intestinal constipation. Intestinal parasite occurred in 22% (mainly giardiasis), gastroesophageal reflux disease in 14%, digestive tract malformations occurred in 5%: 13 cases of duodenal atresia, 8 of imperforate anus, 4 annular pancreases, 2 congenital megacolon, 2 esophageal atresias, 2 esophageal compression by anomalous subclavian and 1 case of duodenal membrane. We had 38/1,207 (3.1%) patients with difficulty in sucking and only three with dysphagia that resolved before the second year of life. Peptic ulcer disease, celiac disease, and biliary lithiasis were less prevalent with 3% each. Awareness of the high prevalence of gastrointestinal disorders promotes outstanding clinical follow-up as well as adequate development and greater quality of life for patients with Down syndrome and their families.

A missense mutation in EBF2 was segregated with imperforate anus in a family across three generations.

The etiology of imperforate anus, a major phenotype of anorectal malformation (ARM), is still unknown and not a single gene has been reported to be associated with it. We studied a Korean family with six affected members with imperforate anus across three generations by whole exome sequencing and identified a missense mutation in the EBF2 gene (c.215C > T; p.Ala72Val). This mutation is completely segregated with the disease phenotype in the family and is evolutionarily highly conserved among diverse vertebrates. Also, this mutation was predicted to be functionally damaging. These results support that missense mutation in the EBF2 c.215C > T (p.Ala72Val) is very likely to contribute to the pathogenesis of ARM in this family.

Hypoxia due to positive pressure ventilation in Edwards' syndrome: A case report.

Edwards' syndrome also known as trisomy 18 is a congenital disorder associated with cardiovascular issues including ventricular septal defect (VSD), atrial septal defect (ASD) and patent duct arteriosus (PDA). An emergency colostomy was performed on a neonate born with an imperforate anus. Pre-operative transthoracic echocardiography showed presence of VSD, a patent foramen ovale (PFO) or ASD. Even though the baby had a good general condition and optimal peripheral oxygen saturation (SpO2), during positive pressure ventilation, she suffered severe hypoxia (50% SpO2). The cause of the hypoxia was thought to be the right-left shunt and so during a second attempt at anaesthesia a vasopressor (noradrenaline 0.03 µg/kg/min) was infused to increase systemic vascular resistance. Thereafter, SpO2 increased to 80-90% and the surgery was completed. The baby recovered without any neurological complications. Genetic testing post-partum showed she had Edwards' syndrome.

Is measuring the residual rectourethral fistula during laparoscopically assisted anorectal pull-through for male high/intermediate type imperforate anus beneficial? Mid-term follow-up.

BACKGROUND/PURPOSE: We evaluated routine intraoperative residual rectourethral fistula measurement (IRRFM) in 20 consecutive male imperforate anus with recto-bulbar (RB; n=12) or recto-prostatic (RP; n=8) fistula during laparoscopically assisted anorectal pull-through (LAARP) for preventing incomplete fistula excision (IFE) on mid-term follow-up. METHODS: Twenty consecutive LAARP performed at a mean age of 10months (range: 3-30) followed-up for a mean of 4.8years (range: 1.5-9) were reviewed. IRRFM involves using a calibrated catheter and a cystoscope to measure the distance between where dissection was ceased at the rectal end and the urethral orifice (Figure). Dissection and IRRFM were repeated until the fistula was <5mm, then tied, and divided. Magnetic resonance imaging (MRI) and pelvic ultrasonography were used to exclude IFE and cyst formation. RESULTS: Residual fistula was 4-18mm on initial IRRFM. Unless measured, dissection cannot proceed to <5mm safely with poentical for urethral injury or IFE. With experience, initial IRRFM were shorter, especially in RP (Table 1). Before the IRRFM era, our incidence of cysts was 2/11 (18%), but here we found no evidence of cyst formation on MRI, no dysuria, and no urinary tract infections. CONCLUSIONS: Mid-term review demonstrates that IFE can be prevented successfully by IRRFM during LAARP. LEVEL OF EVIDENCE: Case Series with no Comparison Group, Level IV.

Differentiating Closed Versus Open Spinal Dysraphisms on Fetal MRI.

OBJECTIVE: The purpose of this study is to identify differences in findings between open and closed spinal dysraphisms seen on fetal MR images. MATERIALS AND METHODS: A single-institution retrospective analysis of fetal MR images for spinal dysraphism was performed. Postnatal images and clinical and operative reports were reviewed. RESULTS: Sixteen fetuses with postnatally confirmed closed spinal dysraphisms were included. Of these, 25% (4/16) had posterior fossa anomalies, 12.5% (2/16) had ventriculomegaly, and 37.5% (6/16) had OEIS (omphalocele, exstrophy, imperforate anus, and spinal defects) complex. Of 90 fetuses with postnatally confirmed open spinal dysraphism, 95.6% (86/90) had posterior fossa anomalies, 85.6% (77/90) had ventriculomegaly, and none had OEIS complex. Twenty fetuses with open spinal dysraphism were randomly selected to compare with fetuses with closed spinal dysraphisms. Continuity of the epidermal and subcutaneous tissues with the sac wall on fetal MR images was seen in 93.8% (15/16) of patients with closed spinal dysraphisms, as opposed to 5% (1/20) of patients with open spinal dysraphisms. The mean (± SD) sac wall thickness was less in open (0.7 ± 0.6 mm) than closed (2.9 ± 1.3 mm; p < 0.001) spinal dysraphism. None of the fetuses had T1-hyperintense fat within the defect. CONCLUSION: On fetal MR images, closed spinal dysraphisms tend to have a sac wall in continuity with the epidermal and subcutaneous tissues, a thicker sac wall, fewer posterior fossa anomalies, and high association with OEIS complex.

Imperforate anus with rectopenile fistula: a case report and systematic review of the literature.

BACKGROUND: Although anorectal malformations (ARMs) are frequently encountered, rare variants difficult to classify have been reported. METHODS: This study describes a patient with ARM and rectopenile fistula. The literature was reviewed systematically to assess the anatomical characteristics, clinical presentations and operations of this rare type of ARM. RESULTS: Eight patients were reported in the six included articles. In three patients, the fistula extended from the rectum to the anterior urethra without communication with the skin. In one patient, the fistula, located deep in corpus spongiosum, opened to the ventral aspect of the penis without communication with the urethra. In the remaining four patients, the fistula extended from the rectum to the cutaneous orifice in the ventral aspect of penis, with communication or a short common channel with the urethra. CONCLUSIONS: Imperforate anus with fistula extending into the penis is a rare variant of anorectal malformation. Unawareness of this lesion resulted in a delay of correct diagnosis and appropriate management. A thorough examination, including colonourethrography and fistulography, should be performed in all patients with a fistula opening in the ventral aspect of the penis.

Effect of folic acid in a modified experimental model of anorectal malformations adriamycin-induced in rats.

PURPOSE: To determine the effect of a single dose of adriamycin (ADR) to induce anorectal malformations (ARMs) and determine the effect of folic acid (FA) in this model. METHODS: Ten female Wistar rats were divided randomly in two groups. Group A - ADR; Group B - FA+ADR. Dams from group B received daily, since two weeks before the pregnancy to the end of pregnancy, FA (50mg/kg) by gavage. Dams from both groups received ADR (6mk/kg) by intraperitoneal injection on gestational day (GD) 8. Their fetuses were harvested by cesarean section on GD21 and were examined looking for ARMs. The thickness of anal stratified squamous epithelium (ASSE) and intestinal epithelium (IE) were analyzed. p≤0.05*. RESULTS: 81 fetuses were harvested. The number of fetuses; number of ARMs; mean (∆%) (± SD) were determined to be, respectively: ADR - 41[29;65%(±37%)] versus FA+ADR - 40[04;16%(±36%)] (p=0.05). AMRs were significantly lower in FA+ADR group than in ADR group (p=0.05). The thickness (µm) of ASSE (± SD) and IE (± SD) were measured, respectively: ADR - [25.98(±0.74) and 19.48(±1.68)] versus FA+ADR - [24.74(±0.91) and 24.80(±0.81)] (p<0.005). The thickness of IE was significantly enlarged when FA was given (p<0.005). CONCLUSIONS: Single dose of adriamycin on D8 was able to induce anorectal malformations. Folic acid reduces the number and enlarged the IE of ARMs ADR-induced.

Effect of folic acid in a modified experimental model of anorectal malformations adriamycin-induced in rats

PURPOSE: To determine the effect of a single dose of adriamycin (ADR) to induce anorectal malformations (ARMs) and determine the effect of folic acid (FA) in this model. METHODS: Ten female Wistar rats were divided randomly in two groups. Group A - ADR; Group B - FA+ADR. Dams from group B received daily, since two weeks before the pregnancy to the end of pregnancy, FA (50mg/kg) by gavage. Dams from both groups received ADR (6mk/kg) by intraperitoneal injection on gestational day (GD) 8. Their fetuses were harvested by cesarean section on GD21 and were examined looking for ARMs. The thickness of anal stratified squamous epithelium (ASSE) and intestinal epithelium (IE) were analyzed. p≤0.05*. RESULTS: 81 fetuses were harvested. The number of fetuses; number of ARMs; mean (∆%) (± SD) were determined to be, respectively: ADR - 41[29;65%(±37%)] versus FA+ADR - 40[04;16%(±36%)] (p=0.05). AMRs were significantly lower in FA+ADR group than in ADR group (p=0.05). The thickness (µm) of ASSE (± SD) and IE (± SD) were measured, respectively: ADR - [25.98(±0.74) and 19.48(±1.68)] versus FA+ADR - [24.74(±0.91) and 24.80(±0.81)] (p<0.005). The thickness of IE was significantly enlarged when FA was given (p<0.005). CONCLUSIONS: Single dose of adriamycin on D8 was able to induce anorectal malformations. Folic acid reduces the number and enlarged the IE of ARMs ADR-induced.

Genetic research and structural dysplasia assessment of anorectal malformations in neonatal male rats induced by di(n-butyl) phthalate.

This study was the first to investigate the genetic abnormalities and structural dysplasia of anorectal malformations (ARMs) in male rats induced by di(n-butyl) phthalate (DBP). DBP was administered to timed-pregnant rats to establish the ARM rat model. The incidence of ARMs in male offspring was 39.5%. In neonatal period, decreased body weight and anogenital distance were observed. The general image and histological analysis of male offspring confirmed the presence of ARMs. Anatomical examination of the ARM male rats revealed the dysplasia in solid organs (heart-lung, liver, spleen, and kidney). The decreases of serum testosterone concentration and androgen receptor expression in terminal rectum were indicative of the antiandrogenic effects of DBP. Moreover, significant decreased mRNA expressions of these androgen-related genes such as sonic hedgehog, Gli2, Gli3, bone morphogenetic protein 4, Wnt5a, Hoxa13, Hoxd13, fibroblast growth factor 10, and fibroblast growth factor receptor 2 were found in terminal rectum of the ARM male pubs. These results demonstrated that development of ARM rats was impaired by maternal exposure to DBP. The antiandrogenic effects of DBP disturbing the androgen-related signaling networks might play an important role in the occurrence of ARMs.

Semilobar Holoprosencephaly Associated with Multiple Malformations in a Foal.

A full-term male foal born in a farm holidays in Maremma (Tuscany, Italy) was euthanized shortly after birth due to the presence of several malformations. The rostral maxilla and the nasal septum were deviated to the right (wry nose), and a severe cervico-thoracic scoliosis and anus atresia were evident. Necropsy revealed ileum atresia and agenesis of the right kidney. The brain showed an incomplete separation of the hemispheres of the rostral third of the forebrain and the olfactory bulbs and tracts were absent (olfactory aplasia). A diagnosis of semilobar holoprosencephaly (HPE) was achieved. This is the first case of semilobar HPE associated with other organ anomalies in horses.

Clarification of mammalian cloacal morphogenesis using high-resolution episcopic microscopy.

The developmental process through which the cloaca transforms from one hollow structure to two separated urinary and digestive outlets remains controversial and speculative. Here, we use high-resolution episcopic microscopy to examine a comprehensive series of normal and mutant mouse cloaca in which the detailed 3-dimensional (3-D) morphological features are illuminated throughout the development. We provide evidence that the dorsal peri-cloacal mesenchyme (dPCM) remains stationary while other surrounding tissues grow towards it. This causes dramatic changes of spatial relationship among caudal structures and morphological transformation of the cloaca. The 3-D characterizations of Dkk1 mutants reveal a hyperplastic defect of dPCM, which leads to a significant anterior shift of the caudal boundary of the cloaca, premature occlusion of the cloaca and, imperforate anus phenotype. Conversely, Shh knockout causes a severe hypoplastic defect of cloaca mesenchyme including dPCM and persistent cloaca. Collectively, these findings suggest that formation of the dPCM is critical for cloacal morphogenesis and furthermore, growth and movement of the mesenchymal tissues towards the dPCM lead to the cloaca occlusion and separation of the urinary and digestive outlets.

Evaluation of postoperative anal functions using endoanal ultrasonography and anorectal manometry in children with congenital anorectal malformations.

PURPOSE: The aim of this study was to assess the postoperative anorectal anatomy and function in children with congenital anorectal malformations (ARM) using endoanal ultrasonography (EUS) and anorectal manometry. METHODS: This study included 47 children who had undergone posterior sagittal anorectoplasty (PSARP) or transperineal anorectoplasty for the repair of an ARM. Children were grouped according to symptoms of defecation disorder, including normal defecation, fecal soiling, fecal incontinence, and constipation. Ten children with no history of anal or rectal diseases served as healthy controls. A well-established scoring system was used for the evaluation of anal function and defecation disorder. RESULTS: EUS showed significant differences in the thickness of the interior sphincter between the ARM patients and the healthy controls (P<0.05). However, no significant difference was found in the thickness of the interior sphincters between the PSARP group and transperineal anorectoplasty group (P>0.05). Anorectal manometry showed that the balloon volumes were significantly different between the surgical group and the control group (P<0.01), and between the low defect group and the intermediate-high defect group (P=0.022). Balloon volume was significantly correlated with anal function scores (r=-0.30, P<0.05). CONCLUSIONS: EUS and anorectal manometry can provide objective assessment of postoperative anorectal anatomy and function in children with ARM.

[Congenital recto-vaginal fistula associated with a normal anus (type H fistula) and rectal atresia in a patient. Report of a case and a brief revision of the literature]. / Asociación de fistula rectovaginal congénita con ano normal (Fístulas Tipo H) y atresia rectal en una paciente. Reporte de un caso y breve revisi6n de la literatura.

Congenital recto-urogenital type fistulas with a normal anus and rectal atresia, represent both anorectal malformations that are infrequently seen in clinical practice. We describe the case of a girl with an association of these two anomalies, together with a double vagina who, on her seventh day of life, expelled feces through her genitals. The malformations were corrected by means of a posterior sagittal approach, descending from the rectum to the anus without perineal dissection. The vaginal septum was resected thru the vulva. There is no evidence of recurrence of the recto-vaginal fistula.

Asociación de fistula rectovaginal congénita con ano normal (Fístulas Tipo H) y atresia rectal en una paciente. Reporte de un caso y breve revisión de la literatura / Congenital recto-vaginal fistula associated with a normal anus (type H fistula) and rectal atresia in a patient. Report of a case and a brief revision of the literature.

Las malformaciones ano-rectales del tipo de fístulas recto-urogenitales congénitas con ano normal y atresia rectal son anomalías poco frecuentes. Se discute el caso de una niña con la asociación de estas dos entidades, acompañada además de una vagina doble, quien fue llevada a la consulta a los siete días de vida por la expulsión de heces a través de los genitales. Las malformaciones fueron corregidas a través de un abordaje sagital posterior, con descenso del recto hasta el ano sin disección perineal. El tabique vaginal fue resecado a través de la vulva. En la actualidad no hay evidencia de recurrencia de la fístula recto-vaginal.

Congenital recto-urogenital type fistulas with a normal anus and rectal atresia, represent both anorectal malformations that are infrequently seen in clinical practice. We describe the case of a girl with an association of these two anomalies, together with a double vagina who, on her seventh day of life, expelled feces through her genitals. The malformations were corrected by means of a posterior sagittal approach, descending from the rectum to the anus without perineal dissection. The vaginal septum was resected thru the vulva. There is no evidence of recurrence of the recto-vaginal fistula.

High resolution MRI for preoperative work-up of neonates with an anorectal malformation: a direct comparison with distal pressure colostography/fistulography.

OBJECTIVE: To compare MRI and colostography/fistulography in neonates with anorectal malformations (ARM), using surgery as reference standard. METHODS: Thirty-three neonates (22 boys) with ARM were included. All patients underwent both preoperative high-resolution MRI (without sedation or contrast instillation) and colostography/fistulography. The Krickenbeck classification was used to classify anorectal malformations, and the level of the rectal ending in relation to the levator muscle was evaluated. RESULTS: Subjects included nine patients with a bulbar recto-urethral fistula, six with a prostatic recto-urethral fistula, five with a vestibular fistula, five with a cloacal malformation, four without fistula, one with a H-type fistula, one with anal stenosis, one with a rectoperineal fistula and one with a bladderneck fistula. MRI and colostography/fistulography predicted anatomy in 88 % (29/33) and 61 % (20/33) of cases, respectively (p = 0.012). The distal end of the rectal pouch was correctly predicted in 88 % (29/33) and 67 % (22/33) of cases, respectively (p = 0.065). The length of the common channel in cloacal malformation was predicted with MRI in all (100 %, 5/5) and in 80 % of cases (4/5) with colostography/fistulography. Two bowel perforations occurred during colostography/fistulography. CONCLUSIONS: MRI provides the most accurate evaluation of ARM and should be considered a serious alternative to colostography/fistulography during preoperative work-up. KEY POINTS: • High-resolution MRI is feasible without the use of sedation or anaesthesia. • MRI is more accurate than colostography/fistulography in visualising the type of ARM. • MRI is as reliable as colostography/fistulography in predicting the level of the rectal pouch. • Colostography/fistulography can be complicated by bowel perforation.

Reduced Wnt3a expression correlates with poor development of the hindgut in rats with anorectal malformations.

Embryogenesis is orchestrated by the wingless-type MMTV integration site family (WNT) signaling pathways, including Wnt3a. This study was performed to investigate the expression of Wnt3a in the terminal hindgut in ethylenethiourea (ETU)-exposed rat embryos with anorectal malformations (ARMs) and its potential association between Wnt3a and the maldevelopment of the terminal hindgut in ARMs. ARM rat embryos were induced by ethylenethiourea on embryonic day 10 (E10). The expression levels of protein and mRNA of Wnt3a were confirmed using immunohistochemistry staining, Western blotting analyses, and quantitative real-time PCR (qRT-PCR) in normal rat and ARM embryos. Immunostaining revealed a variation in the expression of Wnt3a in the developing terminal hindgut of ARM embryos. The expression of Wnt3a in the terminal hindgut of ARM rat embryos decreased at both the mRNA level and protein level (P<0.05) compared with normal tissues. This study demonstrated that the expression of Wnt3a in the ARMs of ETU-exposed rat embryos was remarkably reduced, which indicated its potential role in the pathogenesis of the terminal hindgut maldevelopment in ARMs.

Mutations in PTF1A are not a common cause for human VATER/VACTERL association or neural tube defects mirroring Danforth's short tail mouse.

Danforth's short tail (Sd) mutant mice exhibit defects of the neural tube and other abnormalities, which are similar to the human vertebral anomalies, anal atresia, cardiac defects, tracheosophageal fistula and/or esophageal atresia, renal and radial abnormalities, and limb defects (VATER/VACTERL) association, including defects of the hindgut. Sd has been shown to underlie ectopic gene expression of murine Ptf1a, which encodes pancreas-specific transcription factor 1A, due to the insertion of a retrotansposon in its 5' regulatory domain. In order to investigate the possible involvement of this gene in human VATER/VACTERL association and human neural tube defects (NTDs), a sequence analysis was performed. DNA samples from 103 patients with VATER/VACTERL and VATER/VACTERL­like association, all presenting with anorectal malformations, and 72 fetuses with NTDs, where termination of pregnancy had been performed, were included in the current study. The complete PTF1A coding region, splice sites and 1.5 kb of the 5' flanking promotor region was sequenced. However, no pathogenic alterations were detected. The results of the present study do not support the hypothesis that high penetrant mutations in these regions of PTF1A are involved in the development of human VATER/VACTERL association or NTDs, although rare mutations may be detectable in larger patient samples.