Types of congenital nonsyndromic ichthyoses.

Congenital ichthyoses are a very heterogeneous group of diseases manifested by dry, rough and scaling skin. In all forms of ichthyoses, the skin barrier is damaged to a certain degree. Congenital ichthyoses are caused by various gene mutations. Clinical manifestations of the individual types vary as the patient ages. Currently, the diagnosis of congenital ichthyoses is based on molecular analysis, which also allows a complete genetic counseling and genetic prevention. It is appropriate to refer the patients to specialized medical centers, where the cooperation of a neonatologist, a pediatric dermatologist, a geneticist and other specialists is ensured.

A novel nonsense mutation in the STS gene in a Pakistani family with X-linked recessive ichthyosis: including a very rare case of two homozygous female patients.

BACKGROUND: X-linked ichthyosis (XLI; OMIM# 308100) is a recessive keratinization disorder characterized by the presence of dark brown, polygonal, adherent scales on different parts of the body surface. It almost exclusively affects males and the estimated prevalence ranges from 1:2000-6000 in males worldwide. Extracutaneous manifestations are frequent including corneal opacities, cryptorchidism, neuropsychiatric symptoms or others. Up to 90% of XLI cases are caused by recurrent hemizygous microdeletion encompassing entire STS gene on chromosome Xp22.3, while only a minority of patients shows partial deletions or loss of function point mutations in STS. Larger deletions also involving contiguous genes are identified in syndromic patients. METHODS: Here, we report clinical and genetic findings of a large Pakistani family having 16 affected individuals including 2 females with XLI. Molecular karyotyping and direct DNA sequencing of coding region of the STS gene was performed. RESULTS: The clinical manifestations in affected individuals involved generalized dryness and scaling of the skin with polygonal, dark scales of the skin on scalp, trunk, limbs, and neck while sparing face, palms and soles. There were no associated extra-cutaneous features such as short stature, cryptorchidism, photophobia, corneal opacities, male baldness, and behavioral, cognitive, or neurological phenotypes including intellectual disability, autism or attention deficit hyperactivity disorder. Molecular karyotyping was normal and no copy number variation was found. Sanger sequencing identified a novel hemizygous nonsense mutation (c.287G > A; p.W96*), in exon 4 of STS gene in all affected male individuals. In addition, two XLI affected females in the family were found to be homozygous for the identified variant. CONCLUSIONS: This study is useful for understanding the genetic basis of XLI in the patients studied, for extending the known mutational spectrum of STS, diagnosis of female carriers and for further application of mutation screening in the genetic counseling of this family.

X-linked recessive ichthyosis: an impaired barrier function evokes limited gene responses before and after moisturizing treatments.

BACKGROUND: X-linked recessive ichthyosis (XLRI) is due to deletions or inactivating mutations in the steroid sulfatase (STS) gene. This results in an accumulation of cholesterol sulphate affecting the packing of intercorneocyte lipids. XLRI is characterized by dry, scaly skin and increased skin barrier permeability; patients are often dependent on daily use of moisturizers. OBJECTIVES: To examine the biophysical and molecular changes in the skin of patients with XLRI compared with healthy volunteers, and to analyse the effects of moisturizers on the patients' barrier function. METHODS: Patients with XLRI (n=14) and healthy controls (n=14) were included in the study. Skin dryness score, transepidermal water loss (TEWL) and skin surface pH were monitored at baseline, and punch biopsies were obtained for mRNA expression profiles determined by oligonucleotide arrays. Measurements were repeated in the patients with XLRI after a 4-week treatment with three different moisturizers on the volar forearms. RESULTS: Patients with XLRI showed, compared with healthy controls, increased dryness and TEWL, equal skin pH and altered expression of 27 genes. There were no signs of activation of inflammation or repair pathways. Five selected genes were significantly altered also on quantitative polymerase chain reaction analysis. Treatment with the moisturizers showed similar effects: they improved skin dryness but had no effect on TEWL, pH or expression of selected genes. CONCLUSIONS: Despite a dysfunctional skin barrier, the limited number of genes altered in XLRI skin suggests that no inflammatory or repair mechanisms are triggered. Treatment with moisturizers does not have any major impact on the skin barrier properties of patients with XLRI.

[X-chromosome-linked ichthyosis associated to epilepsy, hyperactivity, autism and mental retardation, due to the Xp22.31 microdeletion]. / Ictiosis ligada al cromosoma X asociada a epilepsia, hiperactividad, autismo y retraso mental, por microdeleción Xp22.31.

X-chromosome-linked ichthyosis is caused by mutation or deletion of the STS gene associated with a deficiency of the enzyme steroid sulphatase, located in the distal part of the short arm of the X chromosome (Xp22.3-pter), close to the pseudo-autosomal region. Depending on its size, it can present as an isolated entity or combined with a syndrome caused by neighbouring genes, thus associating itself with other monogenic diseases as well as other mental disorders. The most relevant findings from the literature review are the importance of the Xp22.3-pter region and the higher incidence of neurological disorders among males (attention deficit hyperactivity disorder, autism and X-linked mental retardation). The role and implication of these genes in the disease are discussed and the authors suggest a possible contribution of the gene PNPLA4, which was originally described as GS2 and codes for calcium-independent phospholipase A2 beta, involved in lipoprotein metabolism, as one of the causes of autism. Improvements have been observed following treatment with citicoline, thanks to the role this nootropic plays in the biosynthesis of structural phospholipids involved in the formation and repair of the neuronal membrane.

Altered serotonergic function may partially account for behavioral endophenotypes in steroid sulfatase-deficient mice.

The X-linked gene STS encodes the steroid hormone-modulating enzyme steroid sulfatase. Loss-of-function of STS, and variation within the gene, have been associated with vulnerability to developing attention deficit hyperactivity disorder (ADHD), a neurodevelopmental condition characterized by inattention, severe impulsivity, hyperactivity, and motivational deficits. ADHD is commonly comorbid with a variety of disorders, including obsessive-compulsive disorder. The neurobiological role of steroid sulfatase, and therefore its potential role in ADHD and associated comorbidities, is currently poorly understood. The 39,X(Y)*O mouse, which lacks the Sts gene, exhibits several behavioral abnormalities relevant to ADHD including inattention and hyperactivity. Here, we show that, unexpectedly, 39,X(Y)*O mice achieve higher ratios than wild-type mice on a progressive ratio (PR) task thought to index motivation, but that there is no difference between the two groups on a behavioral task thought to index compulsivity (marble burying). High performance liquid chromatography analysis of monoamine levels in wild type and 39,X(Y)*O brain tissue regions (the frontal cortex, striatum, thalamus, hippocampus, and cerebellum) revealed significantly higher levels of 5-hydroxytryptamine (5-HT) in the striatum and hippocampus of 39,X(Y)*O mice. Significant correlations between hippocampal 5-HT levels and PR performance, and between striatal 5-HT levels and locomotor activity strongly implicate regionally-specific perturbations of the 5-HT system as a neurobiological candidate for behavioral differences between 40,XY and 39,X(Y)*O mice. These data suggest that inactivating mutations and functional variants within STS might exert their influence on ADHD vulnerability, and disorder endophenotypes through modulation of the serotonergic system.

Recessive x-linked ichthyosis: role of cholesterol-sulfate accumulation in the barrier abnormality.

Cholesterol sulfate is a multifunctional sterol metabolite, produced in large amounts in squamous keratinizing epithelia. Because patients with recessive x-linked ichthyosis display not only a 10-fold increase in cholesterol sulfate, but also a 50% reduction in cholesterol, we assessed here whether cholesterol sulfate accumulation and/or cholesterol deficiency produce abnormal barrier function in recessive x-linked ichthyosis. Patients with recessive x-linked ichthyosis display both an abnormal barrier under basal conditions, and a delay in barrier recovery after acute perturbation, which correlate with minor abnormalities in membrane structure and extensive lamellar-phase separation. Moreover, both the functional and the structural abnormalities were corrected by topical cholesterol. Yet, topical cholesterol sulfate produced both a barrier abnormality in intact skin and extracellular abnormalities in isolated stratum corneum, effects largely reversed by coapplications of cholesterol. Together, these results suggest that cholesterol sulfate accumulation rather than cholesterol deficiency is responsible for the barrier abnormality. Despite the apparent importance of cholesterol sulfate-to-cholesterol processing for normal barrier homeostasis, neither steroid sulfatase activity nor mRNA levels are upregulated following acute perturbations. These results demonstrate both a potential role for cholesterol sulfate-to-cholesterol processing in normal permeability barrier homeostasis, and that basal levels of steroid sulfatase are sufficient to accommodate acute insults to the permeability barrier.

Harlequin baby: a case report.

Harlequin fetus is a rare and the most severe form of congenital ichthyosis. Most of the infants die within a few weeks after birth due to sepsis and respiratory difficulties. The case of a female harlequin baby is reported. The baby survived because of good neonatal intensive care, topical emollients and oral etretinate. Now she is over three years old and the skin developed into congenital non-bullous ichthyosiform erythroderma. Unfortunately she had delayed growth and development. This is the first case report of a harlequin fetus in Thailand that had prolonged survival.

Skin barrier properties in patients with recessive X-linked ichthyosis.

Patients with X-linked recessive ichthyosis (RXLI) were studied as a model of the effect of disturbed epidermal lipid composition on skin barrier function. Thirteen patients with RXLI and 15 age- and sex-matched controls were patch-tested with sodium lauryl sulphate (SLS) 0.5% for 24 h. Basal skin properties and skin response to SLS were studied by measurement of transepidermal water loss (TEWL), electrical capacitance and erythema index. No statistically significant difference in basal TEWL was found between the two groups. The skin response to SLS was found to be statistically significantly increased in controls compared to ichthyosis patients, when evaluated by TEWL. When evaluated by erythema index a statistically significant increase in redness was found in controls, but not in ichthyosis patients. Electrical capacitance, reflecting skin hydration, was significantly reduced in RXLI patients as compared to controls. The water permeability barrier in RXLI patients was not found to be impaired, and skin reactivity was found to be decreased in RXLI patients as compared to controls.

Barrier function parameters in various keratinization disorders: transepidermal water loss and vascular response to hexyl nicotinate.

In this study, we characterized the stratum corneum barrier function in 39 patients with various keratinization disorders (autosomal dominant ichthyosis vulgaris [ADI] [n = 7], X-linked recessive ichthyosis [XRI] [n = 6], autosomal recessive congenital ichthyosis [CI] [n = 10], dyskeratosis follicularis [Darier's disease; DD] [n = 8], erythrokeratoderma variabilis [EKV] [n = 8]), and 21 healthy volunteers, using two non-invasive methods: transepidermal water loss (TEWL) measuring outward transport of water through the skin by evaporimetry, and the vascular response to hexyl nicotinate (HN) penetration into the skin as determined by laser-Doppler flowmetry. Significantly increased TEWL values were found on the volar forearm in all three forms of ichthyosis, compared with the healthy control group, with the highest TEWL values in the CI group. The penetration of HN on the volar forearm was accelerated in patients with ADI, XRI and CI, as indicated by a shorter lag time (t0) between HN application and initial vascular response. However, differentiation between CI and the other ichthyoses was not possible by this method. When using both methods in DD and EKV, no differences compared with the healthy controls could be detected on the volar forearm, where the skin was principally unaffected; only the measurements from the affected skin on alternative sites demonstrated significantly increased TEWL values. In ADI and CI, however, normal-appearing skin also showed impaired values. We conclude that both TEWL and the vascular response to penetration of HN are suitable methods to monitor the skin barrier function in keratinization disorders, and are helpful in discriminating between these disorders.

[Sweat-gland function in patients with X-linked ichthyosis]. / Studio della funzionalità sudoripara in pazienti con ittiosi X-linked.

Literature reports that patients affected by X-linked ichthyosis (XLI) have a reduction of sweat glands and a decrease of sweat production. The sweat physiology of 28 patients, 14 with XLI, 7 with lamellar ichthyosis, 7 with dominant ichthyosis and 28 control subjects were examined with sweat test, performed by pilocarpine iontophoresis. In the same patients we have performed skin biopsy to evaluate quantitative and qualitative reduction of sweat glands.