White forelock, pigmentary disorder of irides, and long segment Hirschsprung disease: possible variant of Waardenburg syndrome

Clinical Insights Into Waardenburg-Shah Syndrome: A Case Series and Literature Review

Researching Waardenburg syndrome (WS) underscores its rarity and complex symptomatology, presenting as a congenital disorder predominantly inherited in an autosomal dominant pattern. It exhibits incomplete penetrance, which results in a wide range of clinical manifestations, with variable phenotypic presentations within the same family as well. The most commonly found features are facial abnormalities, hypopigmentation of the skin, heterochromia iridis, and conductive deafness. Adding to the eccentricities of this syndrome are its four subtypes, each presenting with its specific clinical features, which helps in delineating the subtype. A mutated paired box 3 (PAX3​​​​​) gene manifests as type 1 Waardenburg, which is characterized by sideways displacement of the inner angles of the eyes (i.e., dystopia canthorum), widely spaced eyes, congenital sensorineural hearing impairment, and patchy pigmentation of the iris, skin, and hair. Due to insufficient research, it has been difficult to isolate all the genetic mutations responsible for type 2, but its phenotype is very similar to type 1 with minor differences. Type 3 is characterized by musculoskeletal abnormalities. Waardenburg-Shah syndrome (type 4), which is associated with Hirschsprung disease, is the rarest subtype and is caused by genetic mutations in the endothelin receptor type B (EDNRB), endothelin-3 (EDN3), or sex-determining region Y (SRY) box 10 (SOX10) gene. We present a case series of this unique subtype that presented with a typical history of constipation due to Hirschsprung disease and had phenotypic manifestations of white forelock, heterochromia iridis, and bilateral sensorineural hearing loss (SNHL). In parallel with a positive 1° family history of a white forelock, we reflect on the fundamentals of this unique syndrome, as well as its management protocols, highlighting the importance of genetic counseling and cultivation of a high index of suspicion for its diagnosis.

Waardenburg Syndrome: The Contribution of Next-Generation Sequencing to the Identification of Novel Causative Variants

Waardenburg syndrome (WS) is characterized by hearing loss and pigmentary abnormalities of the eyes, hair, and skin. The condition is genetically heterogeneous, and is classified into four clinical types differentiated by the presence of dystopia canthorum in type 1 and its absence in type 2. Additionally, limb musculoskeletal abnormalities and Hirschsprung disease differentiate types 3 and 4, respectively. Genes PAX3, MITF, SOX10, KITLG, EDNRB, and EDN3 are already known to be associated with WS. In WS, a certain degree of molecularly undetected patients remains, especially in type 2. This study aims to pinpoint causative variants using different NGS approaches in a cohort of 26 Brazilian probands with possible/probable diagnosis of WS1 (8) or WS2 (18). DNA from the patients was first analyzed by exome sequencing. Seven of these families were submitted to trio analysis. For inconclusive cases, we applied a targeted NGS panel targeting WS/neurocristopathies genes. Causative variants were detected in 20 of the 26 probands analyzed, these being five in PAX3, eight in MITF, two in SOX10, four in EDNRB, and one in ACTG1 (type 2 Baraitser-Winter syndrome, BWS2). In conclusion, in our cohort of patients, the detection rate of the causative variant was 77%, confirming the superior detection power of NGS in genetically heterogeneous diseases.

Generation of a heterozygous SOX10 knockout human embryonic stem cell line using CRISPR/Cas9 technology

SOX10 is one of the master transcription factors in neural crest development. Human SOX10 mutations are associated with Waardenburg syndrome type 4 (Waardenburg-Shah, WS4), which can be inherited in both autosomal dominant and recessive patterns. Here, the human embryonic stem cell (hESC) line, H9, was used to generate a heterozygous SOX10 knockout cell line as the in vitro model of WS4 by CRISPR/Cas9-mediated gene targeting. This cell line may represent a valuable tool for uncovering the pathogenesis of WS4.

Juvenile Open-angle Glaucoma With Waardenburg Syndrome: A Case Report

Waardenburg syndrome (WS) is a genetic disorder resulting in anomalies of derivatives of neural crest cells during development. Patients tend to have variable degrees of pigmentary defects affecting skin, hair, and irides in addition to hearing loss and possible systemic neurological associations. Elevation of the intraocular pressure has been reported in several adult patients with WS. We report the first case of WS to be associated with juvenile open-angle glaucoma in a 20-year-old Egyptian man thus expanding the spectrum of the types of glaucoma that can coexist with the syndrome.

[Ophthalmologic manifestations of Waardenburg syndrome]

The Waardenburg syndrome is a group of rare genetic diseases, which clinical manifestations include neurosensory hearing loss, diminished pigmentation of forelock in the frontal region, iris heterochromia, medial canthus dystopia, and the presence of such changes in first-line relatives. The article presents a clinical case of type I Waardenburg syndrome, which developed de novo in a family. This case is unique in its combination of complete bilateral iris heterochromia and impaired choroidal pigmentation. The choroid did not only have hypopigmentation zones, but also large areas of hyper- and depigmentation. Such choroidal changes in Waardenburg patients has not been described in literature before. The diagnosis was confirmed by OCT of the anterior and posterior segments, angio-OCT, fluorescein angiography, indocyanine green angiography, fundus autofluorescence, and electrophysiological studies. The main ophthalmologic diagnostic criterion of Waardenburg syndrome in the present case, beside iris heterochromia, was the detection of iris thickness changes in hyper- and hypopigmentation areas with completely preserved structural and functional properties of the retina and choroid.

Waardenburg-Shah syndrome (WS type IV): a rare case from Pakistan

Waardenburg-Shah syndrome is a rare autosomal recessive [AR] inherited disorder characterized by the presence of Hirschsprung's disease with a high likelihood of aganglionic megacolon, due to which the mortality is high. The management of the condition involves surgical intervention for the removal of the aganglionic segment of the colon. Here, we report a neonate that presented with a white forelock, white eyelashes, iris hypopigmentation, and sensorineural deafness associated with bilious vomiting, refusal to feed, and failure to pass meconium indicating intestinal obstruction.

Identification of Waardenburg Syndrome and the Management of Hearing Loss and Associated Sequelae: A Review for the Pediatric Nurse Practitioner

Waardenburg syndrome (WS) is a rare genetic disorder that is further divided into four subtypes with distinguishing clinical manifestations, categorized by phenotypic variations based on activation or deactivation of six specific gene types. The criteria for clinical diagnosis are established based on these phenotypic variants. While key clinical features may cause suspicion of WS, genetic testing confirms the diagnosis. Pigmentary defects are one of the hallmark features of WS while some individuals may exhibit sensorineural hearing loss, which can be progressive. Audiological treatment is essential to mitigate hearing loss and to minimize speech and language deficits as well as behavior and socioemotional development. Associated complications include musculoskeletal abnormalities and Hirschsprung disease. This article aims to discuss the role of the pediatric nurse practitioner in the early identification, diagnosis, treatment, and long-term management of affected children in the primary care setting.

A homozygous MITF mutation leads to familial Waardenburg syndrome type 4

Waardenburg syndrome (WS) is a genetic disorder characterized by hearing loss and pigmentary abnormalities with variable penetrance. Though heterozygous mutations in MITF are a major cause for Waardenburg syndrome type 2 (WS2), homozygous mutations in this gene and the associated phenotype have been rarely characterized. In this study, we identified a novel p.R223H mutation in MITF in a Chinese Han family with variable WS features. Both parents carried a heterozygous p.R223H mutation. They had normal hearing, and premature greying of the hair is their only pigmentary abnormality. In contrast, their two children both carried a homozygous p.R223H mutation and had classic WS features including profound hearing loss, heterochromia irides and marked pigmentary abnormalities in hair and skin. Interestingly, the two affected children also have persistent chronic constipation since the neonatal period, symptoms suggestive of Waardenburg syndrome type 4 (WS4). Our study revealed a likely association between homozygous mutations in MITF and WS4, which implies a dosage effect for the underlying pathogenesis mechanism.

A novel PAX3 mutation in a Korean patient with Waardenburg syndrome type 1 and unilateral branch retinal vein and artery occlusion: a case report

Background

Waardenburg syndrome (WS) is a very rare genetic disorder affecting the neural crest cells. Coexistence of branch retinal vein occlusion (BRVO) and branch retinal artery occlusion (BRAO) in the same eye is also a rare finding. Here we report a case of WS type 1 that was confirmed by a novel mutation with the finding of unilateral BRVO and BRAO.

Case presentation

A 36-year-old, white-haired Korean man presented with a complaint of loss of vision in the inferior visual field of his right eye and hearing loss. He had telecanthus with a medial eyebrow and a hypochromic left iris. Funduscopy showed an ischemic change at the posterior pole in the right eye with sparing of the foveal center as well as retinal hemorrhages and white patches along the superotemporal arcade. Fundus angiography revealed the presence of both BRVO and BRAO, and optical coherence tomography showed thickening and opacification of the retinal layers corresponding to the ischemic area. A blood workup revealed hyperhomocysteinemia and the presence of antiphospholipid antibodies; both are suggestive as the cause of the BRVO and BRAO. Single nucleotide polymorphism analysis confirmed a novel PAX3 mutation at 2q35 (c.91–95 ACTCC deletion causing a frameshift). These findings confirmed a diagnosis of WS type 1.

Conclusions

WS is a heterogeneous inherited disorder of the neural crest cells that causes pigment abnormalities and sensorineural hearing loss. This is the first report of unilateral BRVO and BRAO in a patient with WS. Furthermore, the PAX3 mutation identified in this patient has not been reported previously.

A Case of Waardenburg-Shah Syndrome Type 4 Presenting with Bilateral Homochromatic Blue Irises from Pakistan

Waardenburg syndrome (WS) is a rare genetic disorder. It is caused by multiple mutations affecting the melanocytes, leading to a multitude of skin, hair, and eye symptoms. It is an autosomal dominant disease with four subtypes, each presenting with varying degrees of sensorineural hearing loss along with a constellation of other symptoms. Hirschsprung disease is unique to Waardenburg-Shah syndrome subtype 4 and is not associated with any other subtype. We present a case of this subtype 4 that presented with a bilateral sensorineural hearing loss, mutism, delayed milestones, white forelock, Hirschsprung disease, and bilateral blue homochromatic irises, a finding which is not typical for this subtype. This is the first case of WS with homochromatic irises and the fourth case to be reported from Pakistan.

Case of Waardenburg Shah syndrome in a family with review of literature

Waardenburg syndrome is a rare disease characterized by sensorineural deafness in association with pigmentary defects. Depending on additional symptoms, WS have been classified into four types. Waardenburg syndrome type 4, also called as Waardenburg Shah Syndrome is a very rare congenital disorder with astounding variable clinical expression, characterized by pigmentary abnormalities of the hair (A white forelock of hair, premature graying) and pigmentary changes of the iris such as heterochromia or homochromia irides, sensorineural deafness and Hirschsprung disease. Three genes have been bestowed so far in consociation with EDNRB, EDN3, and SOX10 genes. The pattern of inheritance is multifarious with the SOX10 mutation affiliation with autosomal dominant inheritance whereas the EDNRB and EDN3 genes are passed down in an autosomally recessive pattern.

Waardenburg syndrome: a rare cause of inherited neuropathy due to SOX10 mutation

Waardenburg syndrome (WS) is a rare disorder comprising sensorineural deafness and pigmentation abnormalities. Four distinct subtypes are defined based on the presence or absence of additional symptoms. Mutations in six genes have been described in WS. SOX10 mutations are usually associated with a more severe phenotype of WS with peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, and Hirschsprung disease. Here we report a 32-year-old man with a novel heterozygous missense variant in SOX10 gene, who presented with congenital deafness, Hirschsprung disease, iris heterochromia, foot deformity, and intermediate conduction velocity length-dependent sensorimotor neuropathy. This case highlights that the presence of other non-neuropathic features in a patient with presumed hereditary neuropathy should alert the clinician to possible atypical rare causes.

Syndromic Hearing Loss: A Brief Review of Common Presentations and Genetics

Congenital hearing loss is one of the most common birth defects worldwide, with around 1 in 500 people experiencing some form of severe hearing loss. While over 400 different syndromes involving hearing loss have been described, it is important to be familiar with a wide range of syndromes involving hearing loss so an early diagnosis can be made and early intervention can be pursued to maximize functional hearing and speech-language development in the setting of verbal communication. This review aims to describe the presentation and genetics for some of the most frequently occurring syndromes involving hearing loss, including neurofibromatosis type 2, branchio-oto-renal syndrome, Treacher Collins syndrome, Stickler syndrome, Waardenburg syndrome, Pendred syndrome, Jervell and Lange-Nielsen syndrome, Usher syndromes, Refsum disease, Alport syndrome, MELAS, and MERRF.

22q11.2q13 duplication including SOX10 causes sex-reversal and peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, Waardenburg syndrome, and Hirschsprung disease

Diagnosis of genetic syndromes may be difficult when specific components of a disorder manifest at a later age. We present a follow up of a previous report [Seeherunvong et al., (2004); AJMGA 127: 149-151], of an individual with 22q duplication and sex-reversal syndrome. The subject's phenotype evolved to include peripheral and central demyelination, Waardenburg syndrome type IV, and Hirschsprung disease (PCWH; MIM 609136). DNA microarray analysis defined the duplication at 22q11.2q13, including SOX10. Sequencing of the coding region of SOX10 did not reveal any mutations. Our data suggest that SOX10 duplication can cause disorders of sex development and PCWH, supporting the hypothesis that SOX10 toxic gain of function rather than dominant negative activity underlies PCWH.

Functional analysis of a SOX10 gene mutation associated with Waardenburg syndrome II

Waardenburg syndrome (WS) is an autosomal dominant inherited non-syndromic type of hereditary hearing loss characterized by varying combinations of sensorineural hearing loss and abnormal pigmentation of the hair, skin, and inner ear. WS is classified into four subtypes (WS1-WS4) based on additional symptoms. WS2 is characterized by the absence of additional symptoms. Recently, we identified a SOX10 missense mutation c.422T > C (p.L141P) associated with WS2. We performed functional assays and found the mutant loses DNA-binding capacity, shows aberrant cytoplasmic and nuclear localization, and fails to interact with PAX3. Therefore, the mutant cannot transactivate the MITF promoter effectively, inhibiting melanin synthesis and leading to WS2. Our study confirmed haploinsufficiency as the underlying pathogenesis for WS2.

Hepatocyte Growth Factor-c-MET Signaling Mediates the Development of Nonsensory Structures of the Mammalian Cochlea and Hearing

The stria vascularis is a nonsensory structure that is essential for auditory hair cell function by maintaining potassium concentration of the scala media. During mouse embryonic development, a subpopulation of neural crest cell-derived melanocytes migrates and incorporates into a subregion of the cochlear epithelium, forming the intermediate cell layer of the stria vascularis. The relation of this developmental process to stria vascularis function is currently unknown. In characterizing the molecular differentiation of developing peripheral auditory structures, we discovered that hepatocyte growth factor (Hgf) is expressed in the future stria vascularis of the cochlear epithelium. Its receptor tyrosine kinase, c-Met, is expressed in the cochlear epithelium and melanocyte-derived intermediate cells in the stria vascularis. Genetic dissection of HGF signaling via c-MET reveals that the incorporation of the melanocytes into the future stria vascularis of the cochlear duct requires c-MET signaling. In addition, inactivation of either the ligand or receptor developmentally resulted in a profound hearing loss at young adult stages. These results suggest a novel connection between HGF signaling and deafness via melanocyte deficiencies.

SIGNIFICANCE STATEMENT

We found the roles of hepatocyte growth factor (HGF) signaling in stria vascularis development for the first time and that lack of HGF signaling in the inner ear leads to profound hearing loss in the mouse. Our findings reveal a novel mechanism that may underlie human deafness DFNB39 and DFNB97. Our findings reveal an additional example of context-dependent c-MET signaling diversity, required here for proper cellular invasion developmentally that is essential for specific aspects of auditory-related organogenesis.

Identification of a de novo mutation of SOX10 in a Chinese patient with Waardenburg syndrome type IV

OBJECTIVES

Waardenburg syndrome is a rare genetic disorder, characterized by the association of sensorineural hearing loss and pigmentation abnormalities. Four subtypes have been classified. The present study aimed to analyze the clinical feature and investigate the genetic cause for a Chinese case of Waardenburg type IV (WS4).

METHODS

The patient and his family members were subjected to mutation detection in the candidate gene SOX10 by Sanger sequencing.

RESULTS

The patient has the clinical features of WS4, including sensorineural hearing loss, bright blue irides, premature graying of the hair and Hirschsprung disease. A novel heterozygous frameshift mutation, c.752_753ins7 (p.Gly252Alafs*31) in the exon 5 of SOX10 was detected in the patient, but not found in the unaffected family members and 100 normal controls. This mutation results in a premature stop codon 31 amino acid downstream.

CONCLUSIONS

The novel mutation c.752_753ins7 (p.Gly252Alafs*31) arose de novo and was considered as the cause of WS4 in the proband. This study further characterized the molecular complexity of WS4 and provided a clinical case for genotype-phenotype correlation studies of different phenotypes caused by SOX10 mutations.

A novel mutation in the endothelin B receptor gene in a moroccan family with shah-waardenburg syndrome

Waardenburg syndrome (WS) is a neurocristopathy disorder combining sensorineural deafness and pigmentary abnormalities. The presence of additional signs defines the 4 subtypes. WS type IV, also called Shah-Waardenburg syndrome (SWS), is characterized by the association with congenital aganglionic megacolon (Hirschsprung disease). To date, 3 causative genes have been related to this congenital disorder. Mutations in the EDNRB and EDN3 genes are responsible for the autosomal recessive form of SWS, whereas SOX10 mutations are inherited in an autosomal dominant manner. We report here the case of a 3-month-old Morrocan girl with WS type IV, born to consanguineous parents. The patient had 3 cousins who died in infancy with the same symptoms. Molecular analysis by Sanger sequencing revealed the presence of a novel homozygous missense mutation c.1133A>G (p.Asn378Ser) in the EDNRB gene. The proband's parents as well as the parents of the deceased cousins are heterozygous carriers of this likely pathogenic mutation. This molecular diagnosis allows us to provide genetic counseling to the family and eventually propose prenatal diagnosis to prevent recurrence of the disease in subsequent pregnancies.

Waardenburg syndrome presenting with constipation since birth

BACKGROUND

Shah-Waardenburg syndrome is Waardenburg syndrome associated with Hirschsprung's disease.

CASE CHARACTERISTICS

A 10-day-old full-term male neonate of Waardenburg syndrome presented with constipation since birth along with features of small bowel obstruction.

OBSERVATION

Exploratory laparotomy revealed distended proximal jejunal and ileal loops along with microcolon; an ileostomy was performed.

OUTCOME

Postoperatively patient developed sepsis and died. Histopathology confirmed total colonic aganglionosis.

MESSAGE

Suspect familial Shah-Waardenburg syndrome in a neonate of Waardenburg syndrome presenting with constipation since birth or intestinal obstruction.

Clinical manifestations of Waardenburg syndrome in a male adolescent in Mali, West Africa

Waardenburg syndrome (WS) is a genetic disorder of which there are four distinct types. These four types are differentiated by the physical defects which they produce. Presented here is the case of a 13-year-old boy with WS Type I who was observed and physically assessed in Mali, West Africa in 1969. His physical findings included a bright blue coloring to the irises of the eyes, profound sensorineural deafness, mutism, dystopia canthorum (lateral displacement of the inner canthi of the eyes), broad nasal root, bushy eyebrows, and scaphoid deformities of the supraorbital portions of the frontal bone. Because family members were not available for interviews or physical examinations, it was not possible to determine if this patient was suffering from a congenital form of the disorder or from a spontaneous mutation. Given the patient's then location in a remote rural area of Mali where electricity was absent, it was not possible to perform additional diagnostic tests. The patient described here is the first with WS in Mali, West Africa to have been medically observed and evaluated and later documented in the medical literature. A second case of the syndrome in Mali was described in the medical literature in 2011 in an 18-month-old infant who did not have sensorineural hearing loss, but who did have a bilateral cleft lip. An historical overview of WS is presented along with details concerning the characteristics of the four types of the disorder.

Identification and functional analysis of a novel mutation in the SOX10 gene associated with Waardenburg syndrome type IV

Waardenburg syndrome type IV (WS4) is a rare genetic disorder, characterized by auditory-pigmentary abnormalities and Hirschsprung disease. Mutations of the EDNRB gene, EDN3 gene, or SOX10 gene are responsible for WS4. In the present study, we reported a case of a Chinese patient with clinical features of WS4. In addition, the three genes mentioned above were sequenced in order to identify whether mutations are responsible for the case. We revealed a novel nonsense mutation, c.1063C>T (p.Q355*), in the last coding exon of SOX10. The same mutation was not found in three unaffected family members or 100 unrelated controls. Then, the function and mechanism of the mutation were investigated in vitro. We found both wild-type (WT) and mutant SOX10 p.Q355* were detected at the expected size and their expression levels are equivalent. The mutant protein also localized in the nucleus and retained the DNA-binding activity as WT counterpart; however, it lost its transactivation capability on the MITF promoter and acted as a dominant-negative repressor impairing function of the WT SOX10.

Genetic Analyses of a Three Generation Family Segregating Hirschsprung Disease and Iris Heterochromia

We present the genetic analyses conducted on a three-generation family (14 individuals) with three members affected with isolated-Hirschsprung disease (HSCR) and one with HSCR and heterochromia iridum (syndromic-HSCR), a phenotype reminiscent of Waardenburg-Shah syndrome (WS4). WS4 is characterized by pigmentary abnormalities of the skin, eyes and/or hair, sensorineural deafness and HSCR. None of the members had sensorineural deafness. The family was screened for copy number variations (CNVs) using Illumina-HumanOmni2.5-Beadchip and for coding sequence mutations in WS4 genes (EDN3, EDNRB, or SOX10) and in the main HSCR gene (RET). Confocal microscopy and immunoblotting were used to assess the functional impact of the mutations. A heterozygous A/G transition in EDNRB was identified in 4 affected and 3 unaffected individuals. While in EDNRB isoforms 1 and 2 (cellular receptor) the transition results in the abolishment of translation initiation (M1V), in isoform 3 (only in the cytosol) the replacement occurs at Met91 (M91V) and is predicted benign. Another heterozygous transition (c.-248G/A; -predicted to affect translation efficiency-) in the 5'-untranslated region of EDN3 (EDNRB ligand) was detected in all affected individuals but not in healthy carriers of the EDNRB mutation. Also, a de novo CNVs encompassing DACH1 was identified in the patient with heterochromia iridum and HSCR Since the EDNRB and EDN3 variants only coexist in affected individuals, HSCR could be due to the joint effect of mutations in genes of the same pathway. Iris heterochromia could be due to an independent genetic event and would account for the additional phenotype within the family.

Shah-Waardenburg syndrome

Shah-Waardenburg syndrome (SWS) is a neurocristopathy and is characterized by Hirschsprung's disease (HD), deafness, and depigmentation of hairs, skin, and iris. Is a very rare congenital disorder with variable clinical expression. This report describes a 4-day-old male newborn with Waardenburg's syndrome associated with aganglionosis of the colon and terminal ileum, and review the relevant literature for draws attention to the causal relationship between these two entities.

Familiar hypopigmentation syndrome in sheep associated with homozygous deletion of the entire endothelin type-B receptor gene

In humans, rodents and horses, pigmentary anomalies in combination with other disorders, notably intestinal aganglionosis, are associated with variants of the endothelin type-B receptor gene (EDNRB). In an inbred Cameroon sheep flock, five white lambs with light blue eyes were sired from the same ram and died within a few hours up to a few days after birth, some of them with signs of intestinal obstruction. The aim of this study was to investigate if the observed hypopigmentation and a possible lethal condition were associated with a molecular change at the ovine EDNRB locus, and to check if such a genetic alteration also occurs in other Cameroon sheep flocks. Sequence analysis revealed a deletion of about 110 kb on sheep chromosome 10, comprising the entire EDNRB gene, on both chromosomes in the two available hypopigmented lambs and on a single chromosome in the two dams and three other unaffected relatives. This micro-chromosomal deletion was also confirmed by quantitative real-time PCR and by fluorescence in situ hybridization. Genotyping of a total of 127 Cameroon sheep in 7 other flocks by duplex PCR did not identify additional carriers of the deletion. Although both hypopigmented lambs available for post-mortem examination had a considerably dilated cecum and remaining meconium, histopathological examination of intestinal samples showed morphologically normal ganglion cells in appropriate number and distribution. This is to our knowledge the first description of an ENDRB gene deletion and associated clinical signs in a mammalian species different from humans and rodents. In humans and rats it is postulated that the variable presence and severity of intestinal aganglionosis and other features in individuals with EDNRB deletion is due to a variable genetic background and multiple gene interactions. Therefore the here analyzed sheep are a valuable animal model to test these hypotheses in another species.

Chromosomal and related Mendelian syndromes associated with Hirschsprung's disease

Hirschsprung's disease (HSCR) is a fairly frequent cause of intestinal obstruction in children. It is characterized as a sex-linked heterogonous disorder with variable severity and incomplete penetrance giving rise to a variable pattern of inheritance. Although Hirschsprung's disease occurs as an isolated phenotype in at least 70% of cases, it is not infrequently associated with a number of congenital abnormalities and associated syndromes, demonstrating a spectrum of congenital anomalies. Certain of these syndromic phenotypes have been linked to distinct genetic sites, indicating underlying genetic associations of the disease and probable gene-gene interaction, in its pathogenesis. These associations with HSCR include Down's syndrome and other chromosomal anomalies, Waardenburg syndrome and other Dominant sensorineural deafness, the Congenital Central Hypoventilation and Mowat-Wilson and other brain-related syndromes, as well as the MEN2 and other tumour associations. A number of other autosomal recessive syndromes include the Shah-Waardenburg, the Bardet-Biedl and Cartilage-hair hypoplasia, Goldberg-Shprintzen syndromes and other syndromes related to cholesterol and fat metabolism among others. The genetics of Hirschsprung's disease are highly complex with the majority of known genetic sites relating to the main susceptibility pathways (RET an EDNRB). Non-syndromic non-familial, short-segment HSCR appears to represent a non-Mendelian condition with variable expression and sex-dependent penetrance. Syndromic and familial forms, on the other hand, have complex patterns of inheritance and being reported as autosomal dominant, recessive and polygenic patterns of inheritance. The phenotypic variability and incomplete penetrance observed in Hirschsprung's disease could also be explained by the involvement of modifier genes, especially in its syndromic forms. In this review, we look at the chromosomal and Mendelian associations and their underlying signalling pathways, to obtain a better understanding of the pathogenetic mechanisms involved in developing aganglionosis of the distal bowel.

Cochlear implantation and congenital deafness: perceptive and lexical results in 2 genetically pediatric identified population

OBJECTIVE

To evaluate the perceptive and linguistic results in 2 predefined genetic population of children with implants.

STUDY DESIGN

Retrospective cohort study.

SETTING

Otolaryngology department of a tertiary referral hospital.

PATIENTS

Among 336 children with prelingual deafness who underwent implantation in our department between 1997 and 2007, 85 with GJB2 gene-related (Cx) deafness and 30 patients with Waardenburg syndrome (WaardS) were included. Mean age at implantation was 4.7 years (range, 15 mo to 16.5 yr) in the Cx group and 4.8 years (range, 16 mo to 16 yr) in the WaardS group. The mean follow-up period was 6.5 years (range, 19 mo to 12 yr) in the Cx group and 7.1 years (range, 27 mo to 13.5 yr) in the WaardS group. More than 75% of the families in both groups scored 4 and 5 when using the Mary Pat Moeller rating (p > 0.05). A psychoneurological evaluation was performed in one third of the patients in both groups.

MAIN OUTCOME MEASURES

Patients underwent linguistic and perceptive evaluations at 12, 24, 36, and 48 months: speech perception with closed-set and open-set words, speech production (Level 1 = vocalizations to Level 5 = complex sentences), and lexical comprehension with EVIP/GaelP (Peabody Picture Vocabulary Test) tests that ranged in 5 levels (-2 SD to +2 SD).

RESULTS

Score results for open-set words were 38.5%, 57.5%, 69%, and 75% in the Cx group and 30.5%, 59%, 67.5%, and 78% in the WaardS group (p > 0.05) at 12, 24, 36, and 48 months. The proportion of children in Levels 4 and 5 of speech production was 27%, 42%, 57.5%, and 58% in the Cx group and 23%, 33%, 55%, and 66% in the WaardS group (p > 0.05). Lexical result at Level -2 SD at 1 year was 90% in the Cx group and 85% in the WaardS group and that at 4 years was 70% in the Cx group and 65% in the WaardS group (p > 0.05).

CONCLUSION

Perceptive and linguistic evolutions for both populations were of good quality, but lexical evaluation showed residual language difficulties in both groups.

Cochlear implant rehabilitation outcomes in Waardenburg syndrome children

OBJECTIVES

The purpose of this study was to review the outcomes of children with documented Waardenburg syndrome implanted in the ENT Department of Centro Hospitalar de Coimbra, concerning postoperative speech perception and production, in comparison to the rest of non-syndromic implanted children.

METHODS

A retrospective chart review was performed for children congenitally deaf who had undergone cochlear implantation with multichannel implants, diagnosed as having Waardenburg syndrome, between 1992 and 2011. Postoperative performance outcomes were assessed and confronted with results obtained by children with non-syndromic congenital deafness also implanted in our department. Open-set auditory perception skills were evaluated by using European Portuguese speech discrimination tests (vowels test, monosyllabic word test, number word test and words in sentence test). Meaningful auditory integration scales (MAIS) and categories of auditory performance (CAP) were also measured. Speech production was further assessed and included results on meaningful use of speech Scale (MUSS) and speech intelligibility rating (SIR).

RESULTS

To date, 6 implanted children were clinically identified as having WS type I, and one met the diagnosis of type II. All WS children received multichannel cochlear implants, with a mean age at implantation of 30.6±9.7months (ranging from 19 to 42months). Postoperative outcomes in WS children were similar to other nonsyndromic children. In addition, in number word and vowels discrimination test WS group showed slightly better performances, as well as in MUSS and MAIS assessment.

CONCLUSIONS

Our study has shown that cochlear implantation should be considered a rehabilitative option for Waardenburg syndrome children with profound deafness, enabling the development and improvement of speech perception and production abilities in this group of patients, reinforcing their candidacy for this audio-oral rehabilitation method.

A novel SOX10 mutation in a patient with PCWH who developed hypoxic-ischemic encephalopathy after E. coli sepsis

We describe a male infant with a novel SOX10 mutation and a severe course of PCWH--a special phenotype of Shah-Waardenburg syndrome involving peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, Waardenburg syndrome, and Hirschsprung's disease. The patient had severe hypoplastic hypoganglionosis of the small and total colonic intestine together with peripheral and central dysmyelination. The patient was completely dependent on parenteral nutrition. We identified a novel frameshift mutation, p.Asp293GlyfsX10, in the SOX10 gene of this patient. The mutation would encode a protein that lacked the transactivation domain and resulted in the largest duplication described to date. At the age of 20 months, the boy presented with a severe complication with a translocation of Escherichia coli and developed sepsis leading to severe hypoxic-ischemic encephalopathy with persistent vegetative state (PVS). The boy died at the age of 24 months.

CONCLUSION

Septic encephalopathy with hypoxic-ischemic encephalopathy can be a serious complication in severe sepsis. It is unknown to what extent the mutant SOX10 protein influenced the degree of brain injury--for example central nervous system susceptibility to hypoxia-during sepsis, which may explain the severe encephalopathy with clinical signs of PVS the boy developed.

Hirschsprung's disease and the brain

A link between factors governing brain development and the development of the ENS is not surprising as both processes are largely controlled by the same or similar neural growth factors which are expressed at more or less in the same spatio-temporal time frame. Hirschsprung's disease (HSCR) occurs as an isolated phenotype in 70% of cases but is associated with other congenital abnormalities and syndromic phenotypes in the remainder, with CNS anomalies making up 6.78%. These associations may be underestimated and are possibly pathogenetically linked to genetic associations and probable gene-gene interaction. In this review we explore known syndromes and other ENS associations of HSCR, looking at possible pathogenetic associations. We point out that borderline cognitive abilities, attention-deficit disorders and possible epileptic seizures in Hirschsprung's patients should be fully investigated. We recognise that this group of patients remain a challenge from a clinical and functional management point of view, and suggest possible management guidelines.

Novel splice mutation in microthalmia-associated transcription factor in Waardenburg Syndrome

Waardenburg Syndrome (WS) is a syndromic form of hearing loss associated with mutations in six different genes. We identified a large family with WS that had previously undergone clinical testing, with no reported pathogenic mutation. Using linkage analysis, a region on 3p14.1 with an LOD score of 6.6 was identified. Microthalmia-Associated Transcription Factor, a gene known to cause WS, is located within this region of linkage. Sequencing of Microthalmia-Associated Transcription Factor demonstrated a c.1212 G>A synonymous variant that segregated with the WS in the family and was predicted to cause a novel splicing site that was confirmed with expression analysis of the mRNA. This case illustrates the need to computationally analyze novel synonymous sequence variants for possible effects on splicing to maximize the clinical sensitivity of sequence-based genetic testing.

Cochlear implantation in Waardenburg syndrome: The Indian scenario

CONCLUSION

Children with Waardenburg syndrome (WS) exhibiting normal inner ear anatomy, like those included in our cohort, derive significant benefit from cochlear implantation and results are comparable to those reported for the general population of implanted children.

OBJECTIVES

The patient population of WS accounts for approximately 2% of congenitally deaf children. The purpose of this retrospective case review was to describe the outcomes for those children with WS who have undergone cochlear implantation.

METHODS

On retrospective chart review, there were four cases with WS who underwent cochlear implantation. These cases were assessed for age at implantation, clinical and radiological features, operative and perioperative course, and performance outcomes. Auditory perception and speech production ability were evaluated using categories of auditory performance (CAP), meaningful auditory integration scales (MAIS), and speech intelligibility rating (SIR) during the follow-up period.

RESULTS

In this group of children with WS, with a minimum follow-up of 12 months, the CAP score ranged from 3 to 5, MAIS from 25 to 30, and SIR was 3. These scores are comparable with those of other cochlear implantees.

A meta-analysis of clinical outcome in patients with total intestinal aganglionosis

Total intestinal aganglionosis (TIA) is the most extreme and rare form of Hirschsprung disease (HD). Until few years ago TIA was considered to be a uniformly fatal condition. Survival has improved in the recent years with the advent of parenteral nutrition, innovative surgical techniques and small bowel transplantation. The purpose of this meta-analysis was to determine the clinical outcome of TIA following various surgical procedures. A meta-analysis of cases of TIA reported in the literature between 1985 and 2009 was performed. Detailed information was recorded regarding the extent of aganglionosis, surgical procedures performed and clinical outcome. In case of survivors, authors of reports were contacted to obtain the up-to-date clinical status of the patient. There were 68 cases of TIA reported worldwide, 40 (58.8%) males and 28 (41.2%) females. 6 (8.8%) patients had extension of aganglionosis up to the stomach, 19 (27.9%) up to the duodenum and 43 (63.2%) patients had aganglionosis up to 20 cm below the duodeno-jejunal flexure. Family history of HD was documented in 10 (14.7%) patients. RET-gene mutation were identified in 10 (71.4%) of the 14 patients investigated of RET germline mutations. Eleven patients (16.2%) died prior to surgical treatment, 25 patients (36.8%) only had jejunostomy, while 20 (29.4%) had Ziegler's myectomy-myotomy. 12 (17.6%) patients received intestinal transplantation (ITx) or combined liver-intestinal transplantation (LITx). Forty-five (66.2%) patients died at ages ranging from 1 day to 8 years. Twenty-three (33.8%) patients were alive; the longest survivor was 10 years old after LITx. Innovative surgical procedures and parenteral nutrition have improved clinical outcome of patients with TIA in recent years. Intestinal transplantation appears promising in the management of TIA.

Waardenburg syndrome with extended aganglionosis: report of 3 new cases

PURPOSE

The Waardenburg-Shah syndrome is an autosomal recessive disease with varied penetration where Hirschsprung's disease and the Waardenburg syndrome are seen together. Although the length of the involved intestinal segment varies in this syndrome, most patients had total colonic aganglionosis with or without small bowel involvement. We present in this study 2 siblings and one first-degree relative for a total of 3 male patients with Waardenburg syndrome and total colonic aganglionosis with or without small bowel involvement, together with their clinical characteristics and treatment methods.

PATIENTS

The patients who presented with intestinal obstruction findings within the first 48 hours after birth were operated on with 2 patients under elective conditions and 1 as an emergency. The ganglionic segment lengths were 6, 8, and 20 cm, respectively. Aganglionic enterostomy was performed, and the Ziegler operation was used for these patients. The enterostomies started to function on the third postoperative week, and they started to gain weight. However, all died because of sepsis on the 5th to 12th month.

CONCLUSION

Waardenburg-Shah syndrome patients have a higher incidence of total colonic aganglionosis with or without small bowel involvement. The Ziegler operation may be used in patients with inadequate ganglionic bowel length to gain some time for the child to grow and to decrease total parenteral nutrition complications.

Aplasia of cochlear nerves and olfactory bulbs in association with SOX10 mutation

A 17-month-old boy was referred with profound sensorineural hearing loss (SNHL), severe visual impairment and developmental delay. Neuroimaging identified hypomyelination and cochlear nerve aplasia. He was noted to have fair skin and hair and multiple areas of cutaneous hyperpigmentation. Previous investigations including karyotype, array comparative genomic hybridization (aCGH) and a full metabolic screen were normal. A novel missense mutation of the highly conserved high mobility group (HMG) domain of SOX10 was identified (Q174P:c.521A>C). This case represents the first description of aplasia of the cochlear nerve due to a SOX10 mutation.

Identification of neural crest and glial enhancers at the mouse Sox10 locus through transgenesis in zebrafish

Sox10 is a dynamically regulated transcription factor gene that is essential for the development of neural crest-derived and oligodendroglial populations. Developmental genes often require multiple regulatory sequences that integrate discrete and overlapping functions to coordinate their expression. To identify Sox10 cis-regulatory elements, we integrated multiple model systems, including cell-based screens and transposon-mediated transgensis in zebrafish, to scrutinize mammalian conserved, noncoding genomic segments at the mouse Sox10 locus. We demonstrate that eight of 11 Sox10 genomic elements direct reporter gene expression in transgenic zebrafish similar to patterns observed in transgenic mice, despite an absence of observable sequence conservation between mice and zebrafish. Multiple segments direct expression in overlapping populations of neural crest derivatives and glial cells, ranging from pan-Sox10 and pan-neural crest regulatory control to the modulation of expression in subpopulations of Sox10-expressing cells, including developing melanocytes and Schwann cells. Several sequences demonstrate overlapping spatial control, yet direct expression in incompletely overlapping developmental intervals. We were able to partially explain neural crest expression patterns by the presence of head to head SoxE family binding sites within two of the elements. Moreover, we were able to use this transcription factor binding site signature to identify the corresponding zebrafish enhancers in the absence of overall sequence homology. We demonstrate the utility of zebrafish transgenesis as a high-fidelity surrogate in the dissection of mammalian gene regulation, especially those with dynamically controlled developmental expression.

Sensorineural deafness, distinctive facial features, and abnormal cranial bones: a new variant of Waardenburg syndrome?

The Waardenburg syndromes (WS) account for approximately 2% of congenital sensorineural deafness. This heterogeneous group of diseases currently can be categorized into four major subtypes (WS types 1-4) on the basis of characteristic clinical features. Multiple genes have been implicated in WS, and mutations in some genes can cause more than one WS subtype. In addition to eye, hair, and skin pigmentary abnormalities, dystopia canthorum and broad nasal bridge are seen in WS type 1. Mutations in the PAX3 gene are responsible for the condition in the majority of these patients. In addition, mutations in PAX3 have been found in WS type 3 that is distinguished by musculoskeletal abnormalities, and in a family with a rare subtype of WS, craniofacial-deafness-hand syndrome (CDHS), characterized by dysmorphic facial features, hand abnormalities, and absent or hypoplastic nasal and wrist bones. Here we describe a woman who shares some, but not all features of WS type 3 and CDHS, and who also has abnormal cranial bones. All sinuses were hypoplastic, and the cochlea were small. No sequence alteration in PAX3 was found. These observations broaden the clinical range of WS and suggest there may be genetic heterogeneity even within the CDHS subtype.

Screening program for Waardenburg syndrome in Colombia: clinical definition and phenotypic variability

A screening program to detect Waardenburg syndrome (WS) conducted between 2002 and 2005, among 1,763 deaf individuals throughout Columbia identified 95 affected individuals belonging to 95 families, giving a frequency of 5.38% of WS among the institutionalized deaf population. We confirmed the clinical diagnosis of WS in the 95 propositi and, through the family evaluation, we also identified 45 non-institutionalized affected relatives. Audiologic, ophthalmologic, and genetic studies were performed to confirm the diagnosis. Following the classification of the WS consortium, based on the Waardenburg Index (WI), to define the type of WS. We classified 62.1% of the propositi as WS2 and 37.9% as WS1. We present here the results of the study of clinical manifestations, analyzing the presence, severity, and symmetry of clinical findings among this affected population. Overall, among the 95 propositi, in addition to sensorineural deafness in all, the most frequent features were broad nasal root (58.9%), a first degree relative affected (37.9%), heterochromia irides (36.8%), skin hypopigmentation (31.6%), white forelock (28.0%), intense blue iris (27.4%), synophrys (12.6%), premature graying (10.5%), ptosis of the eyelids (9.5%), and hypoplasia alae nasi (1.1%). The majority of individuals had normal psychomotor development (87%), while the remaining 13% had developmental delay. Among the latter, 9.4% corresponded to WS2 and 3.6% to WS1. Our data confirm an interesting inter- and intrafamilial variability in the phenotypic manifestations as well as extremely variable expression.

Association of Shah-Waardenburgh syndrome: a review of 6 cases

Shah-Waardenburg syndrome (SWS) is a neurocristopathy and is characterized by Hirschsprung's disease (HD), deafness, and depigmentation of hairs, skin, and iris.

OBJECTIVE

The aim of the article is to study the relative frequency of associations in 6 consecutive cases of SWS.

METHODS

A review of 6 consecutive patients with SWS was performed to study the frequency of various components of the syndrome.

RESULTS

Six patients had features of SWS. All patients had HD; of these, 3 had rectosigmoid HD, whereas 3 had extended HD. All patients had white forelock of hairs with skin depigmentation. One patient had sensorineural deafness, whereas other babies were less than 1 year, and thus, full evaluation of hearing deficiency was not assessed. Three patients had blue eyes, whereas other babies had normal iris pigmentation. Skin depigmentation was noted in 5 of the 6 patients. Three babies were seriously malnourished and showed higher association of enterocolitis.

CONCLUSION

Shah-Waardenburg syndrome is an uncommon association of HD. Depigmentation with a white forelock and skin manifestations are common, whereas blue iris, long segment disease, and enterocolitis are present in nearly half of the patients.

Deletions at the SOX10 gene locus cause Waardenburg syndrome types 2 and 4

Waardenburg syndrome (WS) is an auditory-pigmentary disorder that exhibits varying combinations of sensorineural hearing loss and abnormal pigmentation of the hair and skin. Depending on additional symptoms, WS is classified into four subtypes, WS1-WS4. Absence of additional features characterizes WS2. The association of facial dysmorphic features defines WS1 and WS3, whereas the association with Hirschsprung disease (aganglionic megacolon) characterizes WS4, also called "Waardenburg-Hirschsprung disease." Mutations within the genes MITF and SNAI2 have been identified in WS2, whereas mutations of EDN3, EDNRB, and SOX10 have been observed in patients with WS4. However, not all cases are explained at the molecular level, which raises the possibility that other genes are involved or that some mutations within the known genes are not detected by commonly used genotyping methods. We used a combination of semiquantitative fluorescent multiplex polymerase chain reaction and fluorescent in situ hybridization to search for SOX10 heterozygous deletions. We describe the first characterization of SOX10 deletions in patients presenting with WS4. We also found SOX10 deletions in WS2 cases, making SOX10 a new gene of WS2. Interestingly, neurological phenotypes reminiscent of that observed in WS4 (PCWH syndrome [peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, WS, and Hirschsprung disease]) were observed in some WS2-affected patients with SOX10 deletions. This study further characterizes the molecular complexity and the close relationship that links the different subtypes of WS.