Oligodendrocytes (OLs) assemble myelin sheaths around axons in central nervous system (CNS). Myelin is essential for the saltatory conduction of action potentials and also performs other critical functions for the operation of the CNS. Sox10 (SRY-box containing gene 10) is a high-mobility group transcription factor that orchestrates the development of OLs. Despite its key role in OL biology, there is scant information on how the expression of Sox10 is regulated in OL lineage cells. Especially, OL enhancers that control its transcription remain elusive. We have recently developed an innovative method that rationally links OL enhancers to target genes. This study applied the new method to Sox10, uncovering two OL enhancers for it (termed Sox10-E1 and Sox10-E2). Epigenome editing analysis revealed that Sox10-E1 and Sox10-E2 regulate Sox10 expression non-redundantly. Luciferase assay and human and mouse brain multi-omics data show that, during the differentiation of OL precursor cells (OPCs) into OLs, the enhancer activity of Sox10-E1 does not change while that of Sox10-E2 decreases significantly. Chromatin interaction data indicate that the two Sox10 enhancers lie close to the border of the Sox10 topologically associating domain (TAD). Consistently, Pick1, a gene that is near the Sox10 TAD border, is also under the transcriptional control of Sox10-E1 and Sox10-E2. Hence, genomic deletions involving Sox10-E1 and Sox10-E2 would perturb not only SOX10, but also PICK1 and other genes, and may cause a pathology that is more complex than that of conventional Waardenburg-Shah syndrome that results from SOX10 coding mutations.

The aim was to assess the neuroglial compartment in the myenteric plexus of two subjects with genetically verified Waardenburg syndrome (WS) type 4 (WS4) and to compare the outcome with four "age-matched" controls. Gut samples from four control cases and from two newborn subjects with WS4, one with peripheral demyelinating neuropathy, dysmyelinating leukodystrophy, WS and Hirschprung disease (PCWH) (SOX10, c.769A>T, p.Lys257*) and one with Waardenburg-Shah syndrome (WSS) (EDN3, c.472C>T,p.Arg158Cys)-were assessed histologically and immunohistochemically. Antibodies directed to glial cells (SOX10), ganglion cells (HuC/D), and interstitial cells of Cajal (CD117) were applied. For the child with PCWH syndrome, both the small and large intestine showed a reduction in the number of glial cells (SOX10), in parallel with hypoganglionosis (HuC/D), when compared with "age-matched" controls. In the child with WSS, a severe reduction in the number of glial cells (SOX10) was observed in both the small and large intestine accompanied by aganglionosis (HuC/D) with a skipped segment. The number of interstitial cells of Cajal (CD117) appeared unaffected in both PCWH and WSS cases. A severe reduction of glial cells and a severe reduction or loss of ganglion cells (the number of cells assessed per unit length), were seen in our study subjects when compared with "age-matched" controls. Contrary to the above the presence of Cajal cells was unaffected.

[This corrects the article DOI: 10.1016/j.isci.2024.111680.].

Mutations in the human genes encoding the endothelin ligand-receptor pair EDN3 and EDNRB cause Waardenburg-Shah syndrome (WS4), which includes congenital hearing impairment. The current explanation for auditory dysfunction is defective migration of neural crest-derived melanocytes to the inner ear. We explored the role of endothelin signaling in auditory development in mice using neural crest-specific and placode-specific Ednrb mutation plus related genetic resources. On an outbred strain background, we find a normal representation of melanocytes in hearing-impaired mutant mice. Instead, our results in neural crest-specific Ednrb mutants implicate a previously unrecognized role for glial support of synapse assembly between auditory neurons and cochlear hair cells. Placode-specific Ednrb mutation also caused impaired hearing, resulting from deficient synaptic transmission. Our observations demonstrate the significant influence of genetic modifiers in auditory development, and invoke independent and separable roles for endothelin signaling in the neural crest and placode lineages to create a functional auditory circuitry.

Background: Congenital depigmentation may be associated with congenital sensorineural hearing loss leading to non-development of verbal speech. Objective: To illustrate the clinical features and work-up of 3 children diagnosed with auditory pigmentary disorders (APDs). Methodology: Case series with a review of the literature. Results: The APDs presented here in the 3 children include Waardenburg syndrome type 1, Clouston syndrome, and Waardenburg syndrome type 4 (Waardenburg-Shah syndrome). The characteristic clinical features, audiologic tests, imaging, and the necessary genetic tests carried out subsequently were noted and evaluated. All the children were male and were aged 2 years, 1 year, and 14 months, respectively. All of them had hearing loss and non-development of verbal speech and had some form of oculocutaneous depigmentation. The challenges in the diagnosis, the work-up, and the close differentials were discussed, and the relevant literature was reviewed. Conclusions: The APDs connect congenital depigmentation with prelingual hearing loss through various syndromic disorders. These disorders are not commonly encountered in routine clinical practice; therefore, their proper knowledge is essential for early diagnosis of congenital hearing loss and timely initiation of auditory and speech rehabilitation. This case series deals with a detailed illustration of a few syndromes of the APDs and highlights their clinical presentation and genetic background.