Treatment of keratitis-ichthyosis- deafness (KID) syndrome in children: a case report and review of the literature

Antibody gene transfer treatment drastically improves epidermal pathology in a keratitis ichthyosis deafness syndrome model using male mice

BACKGROUND

Keratitis ichthyosis deafness (KID) syndrome is a rare disorder caused by hemichannel (HC) activating gain-of-function mutations in the GJB2 gene encoding connexin (Cx) 26, for which there is no cure, or current treatments based upon the mechanism of disease causation.

METHODS

We applied Adeno Associated Virus (AAV) mediated mAb gene transfer (AAVmAb) to treat the epidermal features of KID syndrome with a well-characterized HC blocking antibody using male mice of a murine model that replicates the skin pathology of the human disease.

FINDINGS

We demonstrate that in vivo AAVmAb treatment significantly reduced the size and thickness of KID lesions, in addition to blocking activity of mutant HCs in the epidermis in vivo. We also show that AAVmAb treatment eliminated abnormal keratinocyte proliferation and enlarged cell size, decreased apoptosis, and restored the normal distribution of keratin expression.

INTERPRETATION

Our findings reinforce the critical role played by increased HC activity in the skin pathology associated with KID syndrome. They also underscore the clinical potential of anti-HC mAbs coupled with genetic based delivery systems for treating the underlying mechanistic basis of this disorder. Inhibition of HC activity is an ideal therapeutic target in KID syndrome, and the genetic delivery of mAbs targeted against mutant HCs could form the basis of new therapeutic interventions to treat this incurable disease.

FUNDING

Fondazione Telethon grant GGP19148 and University of Padova grant Prot. BIRD187130 to FM; Foundation for Ichthyosis and Related Skin Types (FIRST) and National Institutes of Health grant EY 026911 to TWW.

Keratitis-ichthyosis-deafness syndrome: A comprehensive review of cutaneous and systemic manifestations

Keratitis-ichthyosis-deafness syndrome is a rare genetic disease presenting with cutaneous, ocular, and otic defects. This comprehensive review provides insight into the clinical presentations, highlighting the cutaneous manifestations including histopathology and treatment options.

Keratitis-ichthyosis-deafness Syndrome with Heterozygous p.D50N in the GJB2 Gene in Two Serbian Adult Patients

Purpose

Keratitis-ichthyosis-deafness (KID) syndrome is a rare congenital ectodermal dysplastic syndrome presenting with keratitis, ichthyosis and sensorineural hearing loss. The most common causes of KID syndrome are heterozygous missense mutations in the GJB2 gene that codes for connexin 26.

Case report

During the ophthalmological examination, two adult females complained of recent worsening of visual acuity in both eyes. Anamnesis revealed that their eyes were red and irritated from early childhood onwards. Both of them had thickening and keratinisation of eyelid margins, lash loss, diffuse opacification of cornea and conjunctiva caused by keratinisation of eye surface, superficial and deep corneal vascularisation and corneal oedema. Partial sensorineural hearing loss and difficulties in speech were also noted along with typical ichthyosiform erythroderma. Genetic testing of the GJB2 gene revealed a heterozygous p.D50N mutation in both patients.Patients were treated with a combined topical corticosteroid and artificial tears therapy, with steroid therapy being intensified during the last month. The therapy increased the visual acuity by decreasing corneal oedema and by forming a more regular air-tear interface during the six months follow up. Subsequently, the disease progressed despite the continuation of the therapy.

Conclusion

This is the first report of Serbian patients with KID syndrome. Despite the administration of the combined topical corticosteroid and artificial tears therapy the disease is relentlessly progressive and therapeutic success of ophthalmological signs with local therapeutic modalities used so far had been disappointing.

The Clinical Manifestation of p.Asp50Asn Heterozygous Mutation of GJB2 Gene in 3 Members of a Family Is Similar to That of Clouston Syndrome

Keratitis-ichthyosis-deafness (KID) syndrome has genetic heterogeneity, and the clinical manifestations of some patients may overlap with Clouston syndrome. A 34-year-old female patient came to our department with a complain of “sparse hair, rough skin, photophobia and deafness for more than 30 years.” We found that the proband and two other family members (57-year-old mother and 4-year-old daughter) had similar clinical manifestations: systemic hair loss, generalized skin hyperkeratosis, especially in the metacarpophalangeal area. Subungual hyperkeratosis, finger/toenail dystrophy, as well as photophobia and epiphora. According to the investigation, one of the family members also had similar clinical manifestations (grandfather of the proband) and he’s died. The other three members of the family had no hearing impairment, and all patients had typical nail dystrophy, hair loss and palmoplantar hyperkeratosis, similar like as seen in Clouston syndrome, so we suspected to diagnose the case as Clouston syndrome. However, after genetic testing, it was found that the proband, his mother and daughter all had p.Asp50Asn heterozygous mutations in the GJB2 gene, and no mutation was detected in GJB6. The modified diagnosis was KID syndrome.

Connexin hemichannel inhibition ameliorates epidermal pathology in a mouse model of keratitis ichthyosis deafness syndrome

Mutations in five different genes encoding connexin channels cause eleven clinically defined human skin diseases. Keratitis ichthyosis deafness (KID) syndrome is caused by point mutations in the GJB2 gene encoding Connexin 26 (Cx26) which result in aberrant activation of connexin hemichannels. KID syndrome has no cure and is associated with bilateral hearing loss, blinding keratitis, palmoplantar keratoderma, ichthyosiform erythroderma and a high incidence of childhood mortality. Here, we have tested whether a topically applied hemichhanel inhibitor (flufenamic acid, FFA) could ameliorate the skin pathology associated with KID syndrome in a transgenic mouse model expressing the lethal Cx26-G45E mutation. We found that FFA blocked the hemichannel activity of Cx26-G45E in vitro, and substantially reduced epidermal pathology in vivo, compared to untreated, or vehicle treated control animals. FFA did not reduce the expression of mutant connexin hemichannel protein, and cessation of FFA treatment allowed disease progression to continue. These results suggested that aberrant hemichannel activity is a major driver of skin disease in KID syndrome, and that the inhibition of mutant hemichannel activity could provide an attractive target to develop novel therapeutic interventions to treat this incurable disease.

Consensus recommendations for the use of retinoids in ichthyosis and other disorders of cornification in children and adolescents

Topical and systemic retinoids have long been used in the treatment of ichthyoses and other disorders of cornification. Due to the need for long-term use of retinoids for these disorders, often beginning in childhood, numerous clinical concerns must be considered. Systemic retinoids have known side effects involving bone and eye. Additionally, potential psychiatric and cardiovascular effects need to be considered. Contraceptive concerns, as well as the additive cardiovascular and bone effects of systemic retinoid use with hormonal contraception must also be deliberated for patients of childbearing potential. The Pediatric Dermatology Research Alliance (PeDRA) Use of Retinoids in Ichthyosis Work Group was formed to address these issues and to establish best practices regarding the use of retinoids in ichthyoses based on available evidence and expert opinion.

Clinical, etiopathogenic, and therapeutic aspects of KID syndrome

Keratitis-ichthyosis-deafness (KID syndrome) is a syndromes ichthyoses that is clinically and genetically heterogeneous requiring early and long-term multidisciplinary monitoring of affected individuals. A review of the clinical, etiopathogenic and therapeutic aspects is presented of this rare congenital ectodermal disorder.

Ichthyosis Follicularis, Alopecia, and Photophobia (IFAP) Syndrome: A Case Report and Review of Cases Reported from India

Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome is characterized by the triad of follicular keratotic papules, total to subtotal alopecia, and photophobia. We hereby report a case of IFAP syndrome in a 1-year-old boy who presented with all these classical features along with hyperkeratotic plaques over knees, plantar keratoderma, and umbilical hernia. Also, literature review of cases reported from India is being presented.

Allele-Specific Small Interfering RNA Corrects Aberrant Cellular Phenotype in Keratitis-Ichthyosis-Deafness Syndrome Keratinocytes

Keratitis-ichthyosis-deafness (KID) syndrome is a severe, untreatable condition characterized by ocular, auditory, and cutaneous abnormalities, with major complications of infection and skin cancer. Most cases of KID syndrome (86%) are caused by a heterozygous missense mutation (c.148G>A, p.D50N) in the GJB2 gene, encoding gap junction protein Cx26, which alters gating properties of Cx26 channels in a dominant manner. We hypothesized that a mutant allele-specific small interfering RNA could rescue the cellular phenotype in patient keratinocytes (KCs). A KID syndrome cell line (KID-KC) was established from primary patient KCs with a heterozygous p.D50N mutation. This cell line displayed impaired gap junction communication and hyperactive hemichannels, confirmed by dye transfer, patch clamp, and neurobiotin uptake assays. A human-murine chimeric skin graft model constructed with KID-KCs mimicked patient skin in vivo, further confirming the validity of these cells as a model. In vitro treatment with allele-specific small interfering RNA led to robust inhibition of the mutant GJB2 allele without altering expression of the wild-type allele. This corrected both gap junction and hemichannel activity. Notably, allele-specific small interfering RNA treatment caused only low-level off-target effects in KID-KCs, as detected by genome-wide RNA sequencing. Our data provide an important proof-of-concept and model system for the potential use of allele-specific small interfering RNA in treating KID syndrome and other dominant genetic conditions.

A Rare Case of KID Syndrome: The Use of Hydrosurgery and Strategies for Antiseptic Wound Care

A 14-year-old girl with a history of keratitis-ichthyosis-deafness (KID) syndrome, a rare autosomal dominant condition, was referred to the Department of Plastic Surgery at Brussels University Hospital in June 2016 for progressively worsening inguinoperineal ulceration exacerbated by overapplication of combination drug treclinax (tretinoin and erythromycin). On assessment, a large area of purulent papillomatous hyperkeratosis with follicular plugging, likely superimposed bacterial colonization, and deep ulceration were noted requiring thorough debridement.A first procedure was performed in June 2016 with hydrosurgical debridement (Versajet IITM; Smith & Nephew, Forth Worth, Texas). During the procedure, significant blood loss was noted, and topical adrenaline, blood transfusion, and a short ICU stay were required for monitoring during which the patient remained hemodynamically stable. The wound was primarily dressed with an antimicrobial barrier silver dressing; meropenem, ceftazidime, and fluconazole were started to treat for Gram-negative, Gram-positive, and anaerobic bacilli, as well as Pseudomonas aeruginosa and fungal infections in situ. A further three debridements were required 6, 12, and 26 days after the initial procedure. The patient was discharged 36 days after admission without any antibiotics and with an outpatient wound care plan.Not only was this case rare, but it also reflected the importance of a careful approach when tackling KID syndrome's cutaneous manifestations. Multiple debridements, thorough wound care, and appropriate antibiotic therapy may be required to achieve local healing and a satisfactory result. Hydrosurgical debridement offered a precise and well-controlled method for treating a large ulcerating hyperkeratotic urogenital lesion in this pediatric patient.

Management of congenital ichthyoses: European guidelines of care, part one

These guidelines for the management of congenital ichthyoses have been developed by a multidisciplinary group of European experts following a systematic review of the current literature, an expert conference held in Toulouse in 2016 and a consensus on the discussions. They summarize evidence and expert-based recommendations and are intended to help clinicians with the management of these rare and often complex diseases. These guidelines comprise two sections. This is part one, covering topical therapies, systemic therapies, psychosocial management, communicating the diagnosis and genetic counselling.

Connexin hemichannels influence genetically determined inflammatory and hyperproliferative skin diseases

Connexin mutations underlie numerous human genetic diseases. Several connexin genes have been linked to skin diseases, and mechanistic studies have indicated that a gain of abnormal channel function may be responsible for pathology. The topical accessibility of the epidermal connexins, the existence of several mouse models of human skin disease, and the ongoing identification of pharmacological inhibitors targeting connexins provide an opportunity to test new therapeutic approaches.