Search

Human inborn errors of thymic T cell tolerance underlie the production of autoantibodies (auto-Abs) neutralizing type I IFNs, which predispose to severe viral diseases. We analyze 131 female patients with X-linked dominant incontinentia pigmenti (IP), heterozygous for loss-of-function (LOF) NEMO variants, from 99 kindreds in 10 countries. Forty-seven of these patients (36%) have auto-Abs neutralizing IFN-α and/or IFN-ω, a proportion 23 times higher than that for age-matched female controls. This proportion remains stable from the age of 6 years onward. On imaging, female patients with IP have a small, abnormally structured thymus. Auto-Abs against type I IFNs confer a predisposition to life-threatening viral diseases. By contrast, patients with IP lacking auto-Abs against type I IFNs are at no particular risk of viral disease. These results suggest that IP accelerates thymic involution, thereby underlying the production of auto-Abs neutralizing type I IFNs in at least a third of female patients with IP, predisposing them to life-threatening viral diseases., (© 2024 Rosain et al.)

Background: Early blindness secondary to incurable retinal detachment is one of the main complications of incontinentia pigmenti (IP). The efficiency of ophthalmological management for preventing such evolution has not been proven. The objective of this retrospective study was to report a screening and treatment strategy of the vascular retinopathy in newborns and infants with IP., Results: All files of patients diagnosed with IP within the two first months of life in a single tertiary referral center, between 2010 and 2015, were retrospectively included. The minimum follow-up duration was three years. Patients had undergone systematic indirect ophthalmoscopy examination, looking for signs of peripheric retinal vasculopathy, according to a standardized schedule: at diagnosis, at age 1, 2, 3, 6, 9, 12, 18 and 24 months, and then once a year. Urgent laser therapy was performed under anesthesia in case of signs of retinal ischemia. Nineteen children files (17 girls) were studied. Median age at IP diagnosis was 1 day [0-44]; median age at first retinal evaluation was 25 days. Retinal manifestations occurred in 7 patients (n = 10/38 eyes, 26.3%); they were diagnosed at median age 19 days [3-59]. These patients underwent one or two ablative session per eye (mean 1.7, median 2), under general anaesthesia. No retinal detachment or fold occurred during the follow-up (median 6 years [3-9.8])., Conclusion: Ocular screening should be performed in all cases of IP as soon as possible after diagnosis. A strict ophthalmological monitoring and prophylactic treatment of retinal vasculopathy can efficiently prevent the early blinding complications of the disease.

Background: Incontinentia pigmenti (IP) is a rare multisystemic X-linked dominant genetic disorder characterized by highly diagnostic skin lesions. The disease can be misdiagnosed in infants, and complications affecting the eyes and/or the brain can be severe. Our objective was to highlight the urgency of an appropriate diagnosis and management strategy, as soon as the first symptoms appear, and the need for a well-codified monitoring strategy for each child., Methods: An in-depth literature review using a large number of databases was conducted. The selection criteria for articles were literature review articles on the disease, case series and retrospective studies based on the disease, clinical studies (randomized or not) on treatment, articles discussing patient care and management (treatment, diagnosis, care pathways), and recommendations. The research period was from 2000 until 2018. A group of multidisciplinary experts in IP management was involved, issued from different healthcare providers of the European Network for Rare Skin Diseases (ERN-Skin). The final recommendations have been submitted to two patient representative associations and to a general practitioner and a neonatal specialist prior to their finalization., Results and Conclusion: The diagnosis of IP must be promptly performed to detect potential extracutaneous manifestations, thus allowing the timely implementation of specific therapeutic and monitoring strategies. Eye involvement can be a therapeutic urgency, and central nervous system (CNS) involvement requires a very rigorous long-term follow-up. Assessments and patient support should take into account the possible co-occurrence of various symptoms (including motor, visual and cognitive symptoms)., (© 2020 European Academy of Dermatology and Venereology.)

Background: Incontentia pigmenti (IP) is a rare multisystem disorder of ectodermal origin comprising skin, dental, ocular and central nervous system features. Symptomatic treatments are adapted to each family according to the patient's disability. Due to its rarity, the family IP burden in its broadest sense (psychological, social, economic and physical) has not yet been evaluated., Aim: To design a questionnaire allowing assessing the family burden of IP (F'BoIP)., Method: A questionnaire was developed using a standardized methodology for designing quality of life questionnaires according to the following steps: conception, development, and validation. A multidisciplinary working group was designed, including experts in questionnaire development, dermatologists specialised in IP patient care and representatives of the French IP association. A cultural and linguistic validation into US English was conducted, based on the original French version., Results: A 20-item conceptual questionnaire was generated. Subsequent confirmatory analyses produced a 20-item questionnaire grouped into four domains, demonstrating internal consistency (Cronbach's alpha: 0.93), reproducibility and high reliability. The F'BoIP questionnaire significantly correlated with other validated questionnaires: Family Dermatology Life Quality Index (F-DLQI), Perceived Stress Scale (PSS) and SF-12 mental and SF12 physical scores, indicating good external validity., Conclusion: The F'BoIP questionnaire is the first specific tool to assess the family burden of IP and can be used by both family members of IP patients and by health care professionals. It is a valuable tool which evaluates medical and nonmedical strategies to improve the daily life of families affected by this orphan disease.

Background: Incontinentia pigmenti (IP; MIM308300) is a severe, male-lethal, X-linked, dominant genodermatosis resulting from loss-of-function mutations in the IKBKG gene encoding nuclear factor κB (NF-κB) essential modulator (NEMO; the regulatory subunit of the IκB kinase [IKK] complex). In 80% of cases of IP, the deletion of exons 4 to 10 leads to the absence of NEMO and total inhibition of NF-κB signaling. Here we describe a new IKBKG mutation responsible for IP resulting in an inactive truncated form of NEMO., Objectives: We sought to identify the mechanism or mechanisms by which the truncated NEMO protein inhibits the NF-κB signaling pathway., Methods: We sequenced the IKBKG gene in patients with IP and performed complementation and transactivation assays in NEMO-deficient cells. We also used immunoprecipitation assays, immunoblotting, and an in situ proximity ligation assay to characterize the truncated NEMO protein interactions with IKK-α, IKK-β, TNF receptor-associated factor 6, TNF receptor-associated factor 2, receptor-interacting protein 1, Hemo-oxidized iron regulatory protein 2 ligase 1 (HOIL-1), HOIL-1-interacting protein, and SHANK-associated RH domain-interacting protein. Lastly, we assessed NEMO linear ubiquitination using immunoblotting and investigated the formation of NEMO-containing structures (using immunostaining and confocal microscopy) after cell stimulation with IL-1β., Results: We identified a novel splice mutation in IKBKG (c.518+2T>G, resulting in an in-frame deletion: p.DelQ134_R256). The mutant NEMO lacked part of the CC1 coiled-coil and HLX2 helical domain. The p.DelQ134_R256 mutation caused inhibition of NF-κB signaling, although the truncated NEMO protein interacted with proteins involved in activation of NF-κB signaling. The IL-1β-induced formation of NEMO-containing structures was impaired in fibroblasts from patients with IP carrying the truncated NEMO form (as also observed in HOIL-1 -/- cells). The truncated NEMO interaction with SHANK-associated RH domain-interacting protein was impaired in a male fetus with IP, leading to defective linear ubiquitination., Conclusion: We identified a hitherto unreported disease mechanism (defective linear ubiquitination) in patients with IP., (Copyright © 2017. Published by Elsevier Inc.)

Incontinentia Pigmenti (IP) is a skin disorder with neurological impairment in 30% of cases. The most common disease causing mutation is a deletion of exons 4-10 of the IKBKG gene, located on chromosome Xq28, with skewed X-chromosome inactivation in females, but few cases of random X-inactivation have been reported. We have correlated brain anomalies with X-chromosome inactivation status determined on leucocytes circulating DNA. We reviewed MRI of 18 girls with genetically proven IP. We found three patterns of MRI, normal MRI (n=5), mild white matter abnormalities with cortical and corpus callosum atrophy (n=6), and severe cortical abnormalities suggesting a vascular disease (n=7). Most patients with severe abnormalities had random X-inactivation (6/7,86%), while 80% (4/5) of patients with normal MRI and 100% (6/6) of patients with mild white matter abnormalities had skewed inactivation. These results suggest that skewed chromosome X-inactivation may protect brain from damage, while in case of random inactivation, expression of the mutated IKBKG gene may lead to severe brain lesions., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Incontinentia pigmenti (IP) is an X-linked-dominant Mendelian disorder caused by mutation in the IKBKG/NEMO gene, encoding for NEMO/IKKgamma, a regulatory protein of nuclear factor kappaB (NF-kB) signaling. In more than 80% of cases, IP is due to recurrent or nonrecurrent deletions causing loss-of-function (LoF) of NEMO/IKKgamma. We review how the local architecture of the IKBKG/NEMO locus with segmental duplication and a high frequency of repetitive elements favor de novo aberrant recombination through different mechanisms producing genomic microdeletion. We report here a new microindel (c.436_471delinsT, p.Val146X) arising through a DNA-replication-repair fork-stalling-and-template-switching and microhomology-mediated-end-joining mechanism in a sporadic IP case. The LoF mutations of IKBKG/NEMO leading to IP include small insertions/deletions (indel) causing frameshift and premature stop codons, which account for 10% of cases. We here present 21 point mutations previously unreported, which further extend the spectrum of pathologic variants: 14/21 predict LoF because of premature stop codon (6/14) or frameshift (8/14), whereas 7/21 predict a partial loss of NEMO/IKKgamma activity (two splicing and five missense). We review how the analysis of IP-associated IKBKG/NEMO hypomorphic mutants has contributed to the understanding of the pathophysiological mechanism of IP disease and has provided important information on affected NF-kB signaling. We built a locus-specific database listing all IKBKG/NEMO variants, accessible at http://IKBKG.lovd.nl., (© 2013 WILEY PERIODICALS, INC.)

Incontinentia pigmenti (IP) is a rare X-linked dominant neurocutaneous disorder affecting ectodermal tissue: skin, eyes, central nervous system, hair, nails, and teeth. It is usually lethal for males in utero. The involved gene is NEMO, an essential component of the nuclear factor-kappa B (NF-κB) signaling pathway. Skin lesions are highly diagnostic, occurring in neonates, with a particular distribution on Blaschko lines. The severity of the disease is related to ocular and neurological impairment. The hallmark of ocular IP is retinal vasculopathy including peripheral retinal vascular nonperfusion, macular infarction and neovascularization, and preretinal neovascularization. CNS involvement consists of seizures, mental retardation, hemiparesis, spasticity, microcephaly, cerebellar ataxia, and coma. It often occurs in neonates. Some patients have persistent pharmacoresistant seizures throughout life. MRI findings consist essentially in: white-matter lesions; scattered cortical neuronal necrosis; multiple cerebral infarctions; cerebral atrophy, hypoplasia of the corpus callosum, encephalomalacia and neuronal heterotopia. A predominant role of vascular occlusive phenomena in small vessels is highly suspected. In fact several intricate mechanisms could be discussed: vascular, inflammatory, developmental mechanisms. Their role and predictive factors of IP CNS involvement in neonatal IP need to be better understood to identify effective innovative therapies. Hypomelanosis of Ito can occur in the neonate, infancy, or childhood, be isolated or diffuse, often following the Blaschko lines, and can fade in childhood or adulthood. It is due to reduced melanin in the epidermis. Eye, central nervous (mental retardation, epilepsy, language disabilities, motor system dysfunction, psychiatric symptoms including autism - with frequent cortical malformations including hemimegalencephaly and white matter involvement), and musculoskeletal systems can also be affected. Mosaicism with various chromosomal rearrangements has been reported., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Incontinentia pigmenti (IP) is a multisystem disorder, in which cutaneous symptoms can be accompanied by dental, ocular, and central nervous system defects. In adults, the clinical diagnosis of IP is based principally on the late onset of stage 4 lesions and their association with dental, nail, ocular, or central nervous system anomalies. Nevertheless, these lesions are often unrecognized., Objectives: Our aim was assessment of IP manifestations in adults to clarify diagnostic criteria for mild forms of the disease, to help physicians detect adult IP in the presence of subtle lesions and avoid misdiagnosis., Method: We conducted clinical and histologic examination of 25 adults with IP and nuclear factor-κB essential modulator gene rearrangement or mutations., Results: Linear atrophic, hypopigmented, and hairless lesions (stage 4) are constant in adults. Apoptotic keratinocytes in the epidermis or dermis and atrophic hair follicles, with absence of arrector pili muscles, are frequently observed. In contrast, nipple anomalies are rare., Limitations: We were unable to determine the age of the onset of IP stage 4 lesions., Conclusion: Skin manifestations are constant in adult patients with IP. Histology is characteristic and could be considered as a minor diagnostic criterion of IP. Nipple anomalies also may be considered as a minor criterion. Detection of such subtle manifestations can evoke IP in patients with repeated miscarriages or unexplained neurologic manifestations., (Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Background: Hypochromic streaks can be the only cutaneous sign of incontinentia pigmenti (IP) in adulthood (stage IV). Discovery of such lesions in an adult female with no family history of IP is essential for appropriate genetic counselling., Objective: To describe and to validate the histological features of residual skin lesions in adult IP., Methods: The analysis and comparison of skin biopsies of 26 women affected with molecularly confirmed IP., Results: Most biopsies showed slight atrophy and some scattered apoptotic cells in the epidermis, epidermal hypopigmentation and reduced melanocyte number. The dermis appeared thickened and homogeneous and revealed a complete absence of hair follicles (23/26) and sweat glands (22/26). There was no melanin incontinence or inflammatory cells, and the elastic network was normal., Conclusion: These features lead unequivocally to the diagnosis of a stage IV IP skin lesion. Consequently, histology is a major confirmatory criterion for diagnoses of these mild clinical forms of IP. It is therefore a useful tool in genetic counselling and prenatal diagnosis. Moreover, the observations described here may contribute to understanding the physiopathology of the late stages of IP.

Objective: To analyze the distribution of manifestations in a pediatric cohort and define guidelines for follow-up of incontinentia pigmenti (IP)., Design: Retrospective study of 47 children referred to the Department of Pediatric Dermatology with a diagnosis of IP between 1986 and 1999., Setting: The private or institutional practice of participating dermatologists and pediatricians., Main Outcome Measures: Evaluation of IP clinical diagnosis using the Landy and Donnai criteria., Results: Because hyperpigmentation following the Blaschko lines may be observed in several pigmented disorders, 7 patients were found misdiagnosed. During the neonatal period, erythema, vesicles, and hyperkeratotic le sions were rarely absent in the patients with IP. Ocular and neurological abnormalities were frequent (20% and 30%, respectively) but rarely severe (8% and 7.5%, respectively)., Conclusions: Clinical diagnosis is the first main step for a correct phenotype/genotype correlation, which remains indispensable to better understand the pathological mechanisms of IP and develop new therapies. In doubtful cases, molecular analysis is helpful but characteristic histological features must be added as major criteria for IP diagnosis. Multidisciplinary follow-up is needed, particularly during the first year of life, to detect possible ophthalmologic and neurological complications. Neuroimaging ought to be performed in the case of abnormal neurological examination results or when vascular retinopathy is detected.

Background: Incontinentia pigmenti (IP) is an X-linked genodermatosis that is manifested by neonatal inflammatory vesicles localized along the lines of Blaschko. These lesions usually clear spontaneously within a few months, leaving hyperpigmentation. Ophthalmologic and neurologic symptoms can be associated with IP. Late recurrences of the first-stage inflammatory lesions after the initial rash are uncommon and have been reported infrequently. The mechanism involved in this phenomenon is unclear. However, the recent identification of NEMO/IKKgamma as the gene responsible for IP sheds new light on its pathophysiologic origins., Observations: We report 5 cases of children who experienced episodes of late reactivation of IP. In all cases, the recurrences occurred on the previously hyperpigmented streaks several months or years after resolution of the initial eruptions. In most cases, the recurrences were preceded by an infectious episode., Conclusions: These IP recurrences suggest that mutated cells can persist a long time in the epidermis. We theorize that infections trigger the reactivations. The NEMO/IKKgamma gene encodes a protein essential in nuclear factor kappaB activation, which is required for resistance to tumor necrosis factor alpha-induced apoptosis. We discuss the role of a proinflammatory cytokine such as tumor necrosis factor alpha as a triggering factor for the reactivation.

The transcription factor NF-kappaB regulates the expression of numerous genes controlling the immune and stress responses, inflammatory reaction, cell adhesion, and protection against apoptosis. Incontinentia pigmenti (IP) is the first genetic disorder to be ascribed to NF-kappaB dysfunction. IP is an X-linked dominant genodermatosis antenatally lethal in males. A complex rearrangement of the NEMO (NF-kappaB essential modulator) gene accounts for 85% of IP patients, and results in undetectable NEMO protein and absent NF-kappaB activation. On the other hand, hypohidrotic/anhidrotic ectodermal dysplasia (HED/EDA) has been ascribed to at least three genes also involved in NF-kappaB activation: ectodysplasin (EDA1), EDA-receptor (EDAR) and EDAR-associated death domain (EDARADD). During hair follicle morphogenesis, EDAR is activated by ectodysplasin, and uses EDARADD as an adapter to build a signal transducing complex that leads to NF-kappaB activation. Hence, several forms of HED/EDA also result from impaired activation of the NF-kappaB cascade. Finally, hypomorphic NEMO mutations have been found to cause anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID), whilst stop codon mutations cause a more severe phenotype associating EDA-ID with osteopetrosis and lymphoedema (OL-EDA-ID). The immunological and infectious features observed in patients result from impaired NF-kappaB signalling, including cellular response to LPS, IL-1beta, IL-18, TNF-alpha, Tlr2 and CD40 ligand. Consistently, mouse knockout models have shown the essential role of NF-kappaB in the immune, inflammatory and apoptotic responses. Unravelling the molecular bases of other forms of EDA not associated with mutations in NEMO will possibly implicate other components of the NF-kappaB signalling pathway.

A child with X-linked osteopetrosis, lymphedema, anhidrotic ectodermal dysplasia, and immunodeficiency (OL-EDA-ID) was recently reported. We report the clinical features of a second boy with this novel syndrome and his mother, who presented with signs of incontinentia pigmenti (IP). The child had mild osteopetrosis without neurosensory complications, unilateral lymphedema of the left leg, and characteristic features of anhidrotic ectodermal dysplasia with sparse hair, facial dysmorphy, delayed eruption of teeth, and sweat gland abnormalities. He died at 18 months of severe immunodeficiency with multiple infections caused by Gram-negative (Salmonella enteritidis) and Gram-positive (Streptococcus pneumoniae) bacteria, nontuberculous mycobacteria (Mycobacterium kansasii), and fungi (Pneumocystis carinii). His 30-year-old mother's medical history, together with residual cutaneous lesions, was highly suggestive of IP without neurologic impairment. In this patient with OL-EDA-ID, we detected the same NF-kappaB essential modulator stop codon hypomorphic mutation identified in the previous patient. The occurrence of the same clinical features in 2 unrelated patients with the same genotype demonstrates that OL-EDA-ID is a genuine clinical syndrome. The clinical and biological descriptions of the proband and his mother further corroborate the relationship between IP and EDA. Both syndromes are allelic and are associated with mutations in NF-kappaB essential modulator, with a genotype-phenotype correlation in hemizygous males. In contrast, loss-of-function mutations and hypomorphic mutations may cause IP in females.