5-HT3 Signaling Alters Development of Sacral Neural Crest Derivatives That Innervate the Lower Urinary Tract.

The autonomic nervous system derives from the neural crest (NC) and supplies motor innervation to the smooth muscle of visceral organs, including the lower urinary tract (LUT). During fetal development, sacral NC cells colonize the urogenital sinus to form pelvic ganglia (PG) flanking the bladder neck. The coordinated activity of PG neurons is required for normal urination; however, little is known about the development of PG neuronal diversity. To discover candidate genes involved in PG neurogenesis, the transcriptome profiling of sacral NC and developing PG was performed, and we identified the enrichment of the type 3 serotonin receptor (5-HT3, encoded by Htr3a and Htr3b). We determined that Htr3a is one of the first serotonin receptor genes that is up-regulated in sacral NC progenitors and is maintained in differentiating PG neurons. In vitro cultures showed that the disruption of 5-HT3 signaling alters the differentiation outcomes of sacral NC cells, while the stimulation of 5-HT3 in explanted fetal pelvic ganglia severely diminished neurite arbor outgrowth. Overall, this study provides a valuable resource for the analysis of signaling pathways in PG development, identifies 5-HT3 as a novel regulator of NC lineage diversification and neuronal maturation in the peripheral nervous system, and indicates that the perturbation of 5-HT3 signaling in gestation has the potential to alter bladder function later in life.

Glaucoma and degenerative vitreoretinopathy in a girl with Nicolaides-Baraitser syndrome.

We report the case of a 12-year-old girl diagnosed with Nicolaides-Baraitser syndrome with novel ocular features. Diagnosis was based on clinical features, including developmental delay, sparse hair, and craniofacial features along with de novo mutation in SMARCA2. Eye findings included bilateral glaucoma, cataracts, and degenerative vitreoretinopathy. Given the absence of an associated recognizable disorder and the low prevalence of these ocular findings in the general population, we suggest that these ocular features may not be chance association.

Mitral valve prolapse and aortic root dilation in adults with hypermobile Ehlers-Danlos syndrome and related disorders.

Ehlers-Danlos syndromes (EDSs) are a group of inherited connective tissue disorders, and among them, classical EDS (cEDS) and hypermobile EDS (hEDS) are the most common. Mitral valve prolapse (MVP) and aortic root dilation (ARD) have previously been reported to occur at an increased frequency within cEDS and hEDS. More recently, a study performed in the pediatric population did not show increased prevalence (Ritter et al., American Journal of Medical Genetics Part A, 173(6), 1467-1472, 2017). The purpose of this study was to review a large population of individuals with cEDS, hEDS, and hypermobility spectrum disorders to determine the frequency of MVP and ARD. A retrospective chart review of 209 individuals with echocardiograms was performed. Overall, 6.4% (13/209) had MVP and 1.6% (3/189) were found to have ARD. Although the presence of MVP is higher than what has been reported in the general population, no patients had severe MVP or required surgical intervention. No patients in this cohort had an aortic root diameter requiring surgical repair. Based on the results of this study and previous studies, routine echocardiograms to assess for valvular diseases and ARD may not be necessary unless warranted by presence of symptoms or family history.

Variable Clinical Manifestations of Xia-Gibbs syndrome: Findings of Consecutively Identified Cases at a Single Children's Hospital.

Xia-Gibbs syndrome (XGS) is a recently described neurodevelopmental disorder due to heterozygous loss-of-function AHDC1 mutations. XGS is characterized by global developmental delay, intellectual disability, hypotonia, and sleep abnormalities. Here we report the clinical phenotype of five of six individuals with XGS identified prospectively at the Children's Hospital of Philadelphia, a tertiary children's hospital in the USA. Although all five patients demonstrated common clinical features characterized by developmental delay and characteristic facial features, each of our patients showed unique clinical manifestations. Patient one had craniosynostosis; patient two had sensorineural hearing loss and bicuspid aortic valve; patient three had cutis aplasia; patient four had soft, loose skin; and patient five had a lipoma. Differential diagnoses considered for each patient were quite broad, and included craniosynostosis syndromes, connective tissue disorders, and mitochondrial disorders. Exome sequencing identified a heterozygous, de novo AHDC1 loss-of-function mutation in four of five patients; the remaining patient has a 357kb interstitial deletion of 1p36.11p35.3 including AHDC1. Although it remains unknown whether these unique clinical manifestations are rare symptoms of XGS, our findings indicate that the diagnosis of XGS should be considered even in individuals with additional non-neurological symptoms, as the clinical spectrum of XGS may involve such non-neurological manifestations. Adding to the growing literature on XGS, continued cohort studies are warranted in order to both characterize the clinical spectrum of XGS as well as determine standard of care for patients with this diagnosis.