Locus and allelic heterogeneity and phenotypic variability in Waardenburg syndrome.

Waardenburg syndrome (WS) is a disorder of neural crest cell migration characterized by auditory and pigmentary abnormalities. We investigated a cohort of 14 families (16 subjects) either by targeted sequencing or whole-exome sequencing. Thirteen of these families were clinically diagnosed with WS and one family with isolated non-syndromic hearing loss (NSHL). Intra-familial phenotypic variability and non-penetrance were observed in families diagnosed with WS1, WS2 and WS4 with pathogenic variants in PAX3, MITF and EDNRB, respectively. We observed gonosomal mosaicism for a variant in PAX3 in an asymptomatic father of two affected siblings. For the first time, we report a biallelic pathogenic variant in MITF in a subject with WS2 and a biallelic variant in EDNRB was noted in a subject with WS2. An individual with isolated NSHL carried a pathogenic variant in MITF. Blended phenotype of NSHL and albinism was observed in a subject clinically diagnosed to have WS2. A phenocopy of WS1 was observed in a subject with a reported pathogenic variant in GJB2, known to cause isolated NSHL. These novel and infrequently reported observations exemplify the allelic and genetic heterogeneity and show phenotypic diversity of WS.

A novel mutation of the StAR gene with congenital adrenal hyperplasia and its association with heterochromia iridis: a case report.

BACKGROUND: We report a novel mutation within the StAR gene, causing congenital adrenal hyperplasia, with the so far unreported association with heterochromia iridis. CASE PRESENTATION: In a now 15-year-old girl (born at 41 + 6 weeks of gestation) adrenal failure was diagnosed in the neonatal period based on the clinical picture with spontaneous hypoglycaemia, hyponatremia and an extremely elevated concentration of ACTH (3381 pmol/l; ref. level 1,1-10,1 pmol/l), elevated renin (836 ng/l; ref. level 5-308 ng/l), and a decreased concentration of aldosterone (410 pmol/l; ref. level 886-3540 pmol/l). In addition to hyperpigmented skin the patient exhibited sectorial heterochromia iridis. Sequence analysis of the steroidogenic acute regulatory protein (StAR) gene showed a novel homozygous mutation (c.652G > A (p.Ala218Thr), which was predicted in-silico to be possibly damaging. Under daily steroid substitution her electrolyte levels are balanced while she became obese. Puberty occurred spontaneously. CONCLUSION: A novel mutation in the StAR gene was identified in a patient with severe adrenal hypoplasia and sectorial heterochromia iridis. We discuss a causal relationship between these two rare phenotypes, i.e. whether very high levels of ACTH and alpha-MSH during early development might have disturbed early differentiation and distribution of uveal melanocytes. If confirmed in additional cases, discolorization of the iris might be considered as an additional phenotypical feature in the differential diagnosis of congenital adrenal insufficiency.

Birth palsy in congenital varicella syndrome: A lesson in anatomy.

While brachial plexus palsy sustained due to birth trauma is well known, congenital palsies are decidedly rare. We report such a case caused by congenital varicella syndrome, with associated congenital Horner's syndrome and heterochromia iridis. The surprising juxtaposition of a classic upper plexus palsy and a Horner's syndrome raises points of interest. Similar reports in literature are reviewed, and the genesis of a very characteristic group of findings is discussed.

A genome-wide association study reveals a locus for bilateral iridal hypopigmentation in Holstein Friesian cattle.

BACKGROUND: Eye pigmentation abnormalities in cattle are often related to albinism, Chediak-Higashi or Tietz like syndrome. However, mutations only affecting pigmentation of coat color and eye have also been described. Herein 18 Holstein Friesian cattle affected by bicolored and hypopigmented irises have been investigated. RESULTS: Affected animals did not reveal any ophthalmological or neurological abnormalities besides the specific iris color differences. Coat color of affected cattle did not differ from controls. Histological examination revealed a reduction of melanin pigment in the iridal anterior border layer and stroma in cases as cause of iris hypopigmentation. To analyze the genetics of the iris pigmentation differences, a genome-wide association study was performed using Illumina BovineSNP50 BeadChip genotypes of the 18 cases and 172 randomly chosen control animals. A significant association on bovine chromosome 8 (BTA8) was identified at position 60,990,733 with a -log10(p) = 9.17. Analysis of genotypic and allelic dependences between cases of iridal hypopigmentation and an additional set of 316 randomly selected Holstein Friesian cattle controls showed that allele A at position 60,990,733 on BTA8 (P = 4.0e-08, odds ratio = 6.3, 95% confidence interval 3.02-13.17) significantly increased the chance of iridal hypopigmentation. CONCLUSIONS: The clinical appearance of the iridal hypopigmentation differed from previously reported cases of pigmentation abnormalities in syndromes like Chediak-Higashi or Tietz and seems to be mainly of cosmetic character. Iridal hypopigmentation is caused by a reduced content of melanin pigment in the anterior border layer and iridal stroma. A single genomic position on BTA8 was detected to be significantly associated with iridal hypopigmentation in examined cattle. To our knowledge this is the first report about this phenotype in Holstein Friesian cattle.

A novel variant of the SOX10 gene associated with Waardenburg syndrome type IV.

BACKGROUND: Waardenburg syndrome (WS) is a rare genetic disorder characterized by varying degrees of sensorineural hearing loss and accumulated pigmentation in the skin, hair and iris. The syndrome is classified into four types (WS1, WS2, WS3, and WS4), each with different clinical phenotypes and underlying genetic causes. The aim of this study was to identify the pathogenic variant in a Chinese family with Waardenburg syndrome type IV. METHODS: The patient and his parents underwent a thorough medical examination. We applied whole exome sequencing to identify the causal variant on the patient and other family members. RESULTS: The patient presented with iris pigmentary abnormality, congenital megacolon and sensorineural hearing loss. The clinical diagnosis of the patient was WS4. The whole exome sequencing (WES) revealed a novel variant (c.452_456dup) in the SOX10 gene, which could be responsible for the observed pathogenic of WS4 in this patient. Our analysis suggests that this variant produces a truncated protein that contributes to the development of the disease. The genetic test confirmed the diagnosis of WS4 in the patient from the studied pedigree. CONCLUSIONS: This present study demonstrated that genetic test based on WES, an effective alternative to regular clinical examinations, helps diagnose WS4. The newly identified SOX10 gene variant can expand the understanding of WS4.

XEN45 Gelstent Implantation in the Treatment of Glaucoma Secondary to Fuchs Uveitis Syndrome.

PURPOSE: Evaluation of treatment efficacy of XEN45 gelstent for glaucoma secondary to Fuchs uveitis syndrome (FUS). METHODS: This retrospective case series evaluated patients with glaucoma secondary to FUS, who underwent XEN45 implantation. Complete success was defined as IOP lowering of ≥ 20% and cutoff IOP at ≤18 mmHg. Success was qualified if additional glaucoma medication was necessary. Additional glaucoma surgery except for needling and open bleb revision was regarded as failure. RESULTS: Twelve eyes of 12 patients were included. Qualified and complete success rates were 50% after one year (n = 10). Qualified success was achieved in 66.6% of patients with 33.3% of patients achieving complete success after two years (n = 6). CONCLUSIONS: XEN45 implantation had some success in the treatment of glaucoma secondary to FUS, but needling was frequently necessary to improve outcome.

A comprehensive genotype-phenotype evaluation of eight Chinese probands with Waardenburg syndrome.

BACKGROUND: Waardenburg syndrome (WS) is the most common form of syndromic deafness with phenotypic and genetic heterogeneity in the Chinese population. This study aimed to clarify the clinical characteristics and the genetic cause in eight Chinese WS families (including three familial and five sporadic cases). Further genotype-phenotype relationships were also investigated. METHODS: All probands underwent screening for the known WS-related genes including PAX3, SOX10, MITF, EDNRB, EDN3, and SNAI2 using next-generation sequencing to identify disease-causing genes. Further validation using Sanger sequencing was performed. Relevant findings for the associated genotype-phenotype from previous literature were retrospectively analyzed. RESULT: Disease-causing variants were detected in all eight probands by molecular genetic analysis of the WS genes (SOX10(NM_006941.4): c.544_557del, c.553 C > T, c.762delA, c.336G > A; MITF(NM_000248.3): c.626 A > T; PAX3(NM_181459.4): c.838delG, c.452-2 A > G, c.214 A > G). Six mutations (SOX10:c.553 C > T, c.544_557del, c.762delA; PAX3: c.838delG, c.214 A > G; MITF:c.626 A > T) were first reported. Clinical evaluation revealed prominent phenotypic variability in these WS patients. Twelve WS1 cases and five WS2 cases were diagnosed in total. Two probands with SOX10 mutations developed progressive changes in iris color with age, returning from pale blue at birth to normal tan. Additionally, one proband had a renal malformation (horseshoe kidneys).All cases were first described as WS cases. Congenital inner ear malformations were more common, and semicircular malformations were exclusively observed in probands with SOX10 mutations. Unilateral hearing loss occurred more often in cases with PAX3 mutations. CONCLUSION: Our findings helped illuminate the phenotypic and genotypic spectrum of WS in Chinese populations and could contribute to better genetic counseling of WS.

A Very Rare Association of Fuchs Heterochromic Uveitis and Ectropion Uvea in Usher Syndrome.

Usher syndrome is a heterogeneous genetic disease that is the most common cause of hereditary blindness-deafness. This syndrome is the most prevalent syndrome associated with retinitis pigmentosa. A 25-year-old man referred to us with hearing loss and vision diminution since childhood which has gradually worsened. Visual acuity of both eyes was 20/100. Slit lamp examination of the left eye revealed endothelial stellate keratic precipitates, mild anterior chamber reaction, iris heterochromia, ectropion of uvea, and mild posterior subcapsular cataract. There were also no crypts and abnormal vessels in the left eye iris. His intraocular pressure was 14 mmHg in the right eye and 18 mmHg in the left one. Funduscopy demonstrated waxy pallor optic nerve, marked arterial narrowing, and retinal bone spicule pigment formation in both eyes. We report for the first time a very rare association between Usher syndrome, Fuchs heterochromic uveitis (FHU), and ectropion uvea. To our knowledge, no association has been reported between ectropion uvea, FHU, and Usher syndrome.

A case of unilateral sectoral iris heterochromia in an infant with Beckwith-Wiedemann syndrome.

PURPOSE: To report a case of unilateral sectoral iris heterochromia in an infant with Beckwith-Wiedemann syndrome (BWS). OBSERVATIONS: An 8-month-old girl known case of BWS, due to hypomethylation of the DMR2 (KCNQ1OT1) on chromosome 11p15.5, with features of macroglossia, neonatal hypoglycaemia and an unusual finding of partial iris hypopegmentaion in her left eye. CONCLUSIONS: This is the first reported case of iris heterochromia in a BWS patient. Further studies are needed to support the association between eye findings and BWS related genetic defects.

Case Report: A Novel PAX3 Mutation Associated With Waardenburg Syndrome Type 1.

Background: Waardenburg Syndrome Type 1 (WS1) is a rare hereditary disease, which is usually caused by the mutations of PAX3 (paired box 3). Here, we reported a pedigree with WS1, which was caused by a novel mutation in PAX3. Case Report: In this present report, a 10-year-old boy and his twin sister from a Han Chinese family presented with iris pigmentary abnormality, synophrys, and broad and high nasal root. Their father presented premature whitening of the hair, but no iris pigmentary abnormality. Their aunts presented the same clinical characteristics with the twins and premature graying of hair. However, none of the patients reported hearing loss. The clinical diagnosis of the four patients from this pedigree was WS1. The whole exome sequencing (WES) revealed a novel mutation (c.959-5T>G) in the PAX3 gene, which could be responsible for the observed pathogenic of WS1 in this pedigree. The genetic test confirmed the diagnosis of WS1 in the four patients from the studied pedigree. Conclusion: This present study demonstrated that genetic test based on WES, an effective alternative to regular clinical examinations, helps diagnose WS1. The newly identified PAX3 gene mutation can expand the understanding of WS1.

Post-thyroidectomy iatrogenic Horner's syndrome with heterochromia.

PURPOSE: To present a case of iatrogenic Horner's syndrome seen together with the heterochromia in the post-thyroidectomy period. METHODS: A 23-year-old female patient was admitted to our clinic with complaints of low vision in the eye and difference in eye color that developed over the past two years. In the left eye, myosis and minimal ptosis (∼1 mm) was detected, and the color of the iris was lighter than the right eye. RESULTS: The pre-diagnosis of left iatrogenic Horner's syndrome was finalized after 0.5% topical apraclonidine test. CONCLUSION: Heterochromia can be observed in iatrogenic Horner's syndrome.

A Case of Woolly Hair Nevus Associated with Pigmentary Demarcation Lines and Heterochromia Iridis: Coincidence or a New Association?

We report a case of woolly hair nevus with pigmentary demarcation lines and heterochromia iridis. Woolly hair nevus is a rare abnormality of the scalp hair characterized by the patch of hair, which is curlier and light colored than the rest of the scalp hair. Association of woolly hair nevus with some other ectodermal defects effecting skin and eyes has been reported before. Here, woolly hair nevus associated with demarcation lines and heterochromia iridis, to our knowledge, have not been previously reported.

Congenital horner syndrome with heterochromia iridis associated with ipsilateral internal carotid artery hypoplasia.

BACKGROUND: Horner syndrome (HS), also known as Claude-Bernard-Horner syndrome or oculosympathetic palsy, comprises ipsilateral ptosis, miosis, and facial anhidrosis. CASE REPORT: We report herein the case of a 67-year-old man who presented with congenital HS associated with ipsilateral hypoplasia of the internal carotid artery (ICA), as revealed by heterochromia iridis and confirmed by computed tomography (CT). CONCLUSIONS: CT evaluation of the skull base is essential to establish this diagnosis and distinguish aplasia from agenesis/hypoplasia (by the absence or hypoplasia of the carotid canal) or from acquired ICA obstruction as demonstrated by angiographic CT.

Congenital Horner Syndrome with Heterochromia Iridis Associated with Ipsilateral Internal Carotid Artery Hypoplasia

BACKGROUND: Horner syndrome (HS), also known as Claude-Bernard-Horner syndrome or oculosympathetic palsy, comprises ipsilateral ptosis, miosis, and facial anhidrosis. CASE REPORT: We report herein the case of a 67-year-old man who presented with congenital HS associated with ipsilateral hypoplasia of the internal carotid artery (ICA), as revealed by heterochromia iridis and confirmed by computed tomography (CT). CONCLUSIONS: CT evaluation of the skull base is essential to establish this diagnosis and distinguish aplasia from agenesis/hypoplasia (by the absence or hypoplasia of the carotid canal) or from acquired ICA obstruction as demonstrated by angiographic CT.