Steroid sulphatase deficiency disease

Transporter for sulfated steroid hormones in the testis - expression pattern, biological significance and implications for fertility in men and rodents

In various tissues, steroid hormones may be sulfated, glucuronidated or otherwise modified. For a long time, these hydrophilic molecules have been considered to be merely inactive metabolites for excretion via bile or urine. Nevertheless, different organs such as the placenta and breast tissue produce large amounts of sulfated steroids. After the discovery of the enzyme steroid sulfatase, which is able to re-activate sulfated steroids, these precursor molecules entered the focus of interest again as a local supply for steroid hormone synthesis with a prolonged half-life compared to their unconjugated counterparts. The first descriptions of this so-called sulfatase pathway in the placenta and breast tissue (with special regards to hormone-dependent breast cancer) were quickly followed by studies of steroid sulfate production and function in the testis. These hydrophilic molecules may not permeate the cell membrane by diffusion in the way that unbound steroids can, but need to be transported through the plasma membrane by transport systems. In the testis, a functional sulfatase pathway requires the expression of specific uptake carrier and efflux transporters in testicular cells, i.e. Sertoli, Leydig and germ cells. Main focus has to be placed on Sertoli cells, as these cells build up the blood-testis barrier. In this review, an overview of carrier expression pattern in the human as well as rodent testis is provided with special interest towards implications on fertility.

Clinico-epidemiological Study of Congenital Ichthyosis in a Tertiary Care Center of Eastern India

Background

Congenital ichthyoses comprises various specific genetic diseases and can range from mild to very severe presentation. Furthermore, these may be associated with various syndromes. There is scanty data regarding the demographic profile and clinical features of patients with congenital ichthyosis in India.

Aims and Objectives

The aim is to evaluate the epidemiology and clinical characteristics of various types of congenital ichthyoses.

Materials and Methods

The study was conducted for 1 year from April 2013 to March 2014. Patients were evaluated for epidemiological profile and clinical features.

Results

During the study of 1 year, 106 patients of congenital ichthyoses were identified. The most common of the various ichthyoses was ichthyosis vulgaris, followed by lamellar ichthyosis, X-linked recessive ichthyosis. One case of Netherton syndrome and one of ichthyosis hystrix were also identified.

Conclusion

Various types of congenital ichthyoses present with different clinical features which range from mild to severe. These present with significant psychological stress to both patients and their families. Furthermore, all these diseases have significant implications of transmission to their offspring.

Ocular manifestations, complications and management of congenital ichthyoses: a new look

Congenital ichthyoses (CI) are rare genetic skin keratinisation diseases characterised by generalised scaling and a variable degree of erythema and hyperkeratosis. Ocular involvement includes the eyelids, conjunctiva and all layers of the cornea. Ophthalmic input should include regular slit lamp review with the primary aim to prevent a corneal epithelial defect, secondary bacterial infection, scarring or perforation. This review highlights the current literature regarding ophthalmic findings and management of CI.

Pre-Descemet corneal dystrophy and X-linked ichthyosis associated with deletion of Xp22.31 containing the STS gene

PURPOSE

To report the association of X-linked ichthyosis and pre-Descemet corneal dystrophy with a deletion of the steroid sulfatase gene (STS) detected with microarray-based comparative genomic hybridization (aCGH).

METHODS

A slit-lamp biomicroscopic examination and cutaneous examination were performed, after which a saliva sample was collected as a source of genomic DNA. Polymerase chain reaction amplification of each of the 10 exons of STS was performed, as was aCGH on genomic DNA to detect copy number variation.

RESULTS

The slit-lamp examination revealed punctate opacities in the posterior corneal stroma of each eye. The cutaneous examination demonstrated scaling and flaking skin of the arms and legs. Polymerase chain reaction amplification using primers designed to amplify each of the 10 exons of STS failed to produce any amplicons. Subsequently, aCGH performed on genomic DNA revealed a microdeletion in the Xp22.31 cytoband of approximately 1.7 megabases, containing STS.

CONCLUSIONS

The identification of a microdeletion within Xp22.3 containing STS with aCGH in an individual with suspected pre-Descemet corneal dystrophy and X-linked ichthyosis demonstrates the clinical utility of copy number variation analysis in confirming a presumptive clinical diagnosis.

Resource utilization and quality of life associated with congenital ichthyoses

We explored resource utilization (ResUtil) and quality of life (QOL) associated with congenital ichthyoses (CI). Subjects completed an online survey related to clinical severity, demographics, ResUtil, and QOL as measured according to the Dermatology Life Quality Index (DLQI). Validated Likert scales were used to evaluate severity of hyperkeratosis, erythema, and alopecia. ResUtil was determined according to time spent daily treating CI symptoms (TimeTx) and number of ichthyosis-related dermatology visits (DermVisits) per year. We used linear regression to investigate predictors of a transformed DLQI (sqrtDLQI) and logistic regression for ResUtil. Of 235 subjects, 60.2% were female, 83.8% were Caucasian, 42.3% had a family history (FamHx) of CI, and the mean age was 28.7 years (SD 20.3). Predictors for worse QOL were hyperkeratosis severity (β = 0.27, p < 0.01), erythema (β = 0.27, p < 0.01), TimeTx (β = 0.21, p < 0.01), ichthyosis type (β = 0.09, p < 0.01), and age (β = 0.01, p = 0.02). Predictors for DermVisits were hyperkeratosis severity (odds ratio [OR] = 1.38, 95% confidence limit [CL] = 1.01, 1.87), FamHx (OR = 0.28, 95% CL = 0.09, 0.85), age (OR = 0.97, 95% CI = 0.96, 0.99), and alopecia severity (OR = 1.43, 95% CL = 1.12, 1.82). Predictors for treatment duration were erythema (OR = 1.35, 95% CL = 1.02, 1.78), age (OR = 0.98, 95% CL = 0.96, 0.99), and DLQI (OR = 1.09, 95% CL = 1.03, 1.15). Increased hyperkeratosis severity and erythema negatively impact QOL in the CI. Furthermore, increased disease severity predicted greater ResUtil, whereas increased age and FamHx predicted less ResUtil. Our findings suggest that better therapies and increased patient education may improve QOL and decrease ResUtil.

Exacerbation of X-linked ichthyosis phenotype in a female by inheritance of filaggrin and steroid sulfatase mutations

BACKGROUND

X-linked ichthyosis (XLI) is a relatively common, recessive condition caused by mutations in the steroid sulfatase (STS) gene. Common loss-of-function mutations in the filaggrin gene (FLG) cause ichthyosis vulgaris and predispose individuals to atopic eczema.

OBJECTIVE

To test the hypothesis that co-inheritance of FLG mutations can act as a genetic modifier in XLI.

METHODS

An unusually severe XLI phenotype in addition to eczema and mild childhood asthma was investigated in a female Indian patient by fluorescent in situ hybridization (FISH) for the common STS gene deletion. Direct sequencing of the entire FLG gene was also performed.

RESULTS

FISH analysis revealed that the proband was homozygous for the common STS genomic deletion mutation. Further investigation revealed a frame-shift mutation 3672del4 in the gene encoding filaggrin (FLG), leading to premature termination of profilaggrin translation. Interestingly, her father, who had a very typical mild presentation of XLI, did not carry this FLG mutation in addition to his STS deletion. Her mother was a heterozygous carrier of the FLG mutation and consistent with this, had mild symptoms of ichthyosis vulgaris; she was also a heterozygous carrier of the STS deletion.

CONCLUSION

This is the second reported case of the modifying effects of FLG null alleles on XLI and strengthens the hypothesis that filaggrin defects can synergize with STS deficiency to exacerbate the ichthyosis phenotype.

Ichthyoses - Part 1: Differential diagnosis of vulgar ichthyoses and therapeutic options

Ichthyoses are a group of genetic disorders with defective cornification, clinically characterized by scaling of the skin. Additionally, distinctive cutaneous inflammation can often be observed. For most of the patients these diseases lead to a significant restriction in quality of life. The diagnostic criteria include clinical and histological findings, often confirmed by specialized tests. Because many of the ichthyoses are extremely rare, their accurate diagnosis is often carried out in specialized centers. We summarize isolated vulgar and congenital ichthyoses both with and without associated symptoms and focus on the common genetic changes and their clinical phenotype. Specific therapies are still not available for most of these genetic disorders. The use of different topical agents (e. g. urea, retinoids and salicylic acid) and baths followed by mechanical keratolysis (sometimes in combination with systemic retinoids) reduce symptoms. Patients with uncommon congenital ichthyoses often benefit from interdisciplinary management which involves specialized dermatological centers. In this first part of the paper the vulgar ichthyoses as well as the diagnostic and therapeutic options are discussed. The second part focuses on the congenital ichthyoses and their differential diagnosis.

The spectrum of skin disease among Indian children

Skin diseases in children are encountered frequently and their characterization is essential for the preparation of academic, research and health plans. A retrospective study was designed to evaluate the epidemiologic features of pediatric dermatoses in India. The setting was a tertiary care referral center in India (Kalawati Saran Children's Hospital, New Delhi) during January 1997 to December 2003. A total of 30,078 children less than 12 years of age with 32,341 new dermatoses were recorded, with a male to female ratio of 1.07:1. Most of the disease was seen in the 1- to 5-year age group (44.94%). The most common skin diseases were infections and infestations (47.15%) consisting of bacterial infections (58.09%) and scabies (21.54%), followed by eczemas (26.95%), infantile seborrheic dermatitis, scabies, and pityriasis alba. Other unique dermatoses in our settings were papular uticaria (3.59%), miliaria (5.46%), postinflammatory pigmentary abnormalities (1.68%), and nutritional deficiency dermatoses (0.45%). A majority of patients were diagnosed clinically and special diagnostic tests were conducted in 2.6% of patients. The most common diagnostic test used was KOH mount (59.2%), followed by skin biopsy (39%). Nearly 90% of patients were seen without any referral and in the remaining, a majority were referred by pediatricians (75%). A majority of patients were diagnosed to have infection followed by dermatitis in our setting.

Molecular genetics of the ichthyoses

The ichthyoses are a large, clinically, genetically, and etiologically heterogeneous group of disorders of cornification due to abnormal differentiation and desquamation of the epidermis. Although they differ in clinical features, inheritance, and structural and biochemical abnormalities of the epidermis, they often pose a diagnostic challenge. For each of the 12 ichthyoses and related disorders described here, the major disease genes have been identified and genotype-phenotype correlation have begun to emerge. The molecular findings reveal the functional importance and interactions of many different epidermal proteins and metabolic pathways, including major structural proteins (keratins, loricrin), enzymes involved in lipid metabolism (transglutaminase 1, lipoxygenases, fatty aldehyde dehydrogenase, steroid sulfatase, glucocerebrosidase, Delta8-Delta7 sterol isomerase, 3beta-hydroxysteroid dehydrogenase), and protein catabolism (LEKTI), peroxisomal transport and processing (Peroxin 7 receptor, Phytanoyl-CoA hydroxylase) and DNA repair (proteins of the transcription repair complex). This review highlights the spectacular advances in the molecular genetics and biology of heritable ichthyoses over the past decade. It illustrates the power of molecular diagnostics for refining disease classification, providing prenatal diagnosis, improving genetic counseling, and clinical management.

Chromosomes, genes, and development of testicular germ cell tumors

A literature review found 265 articles on testicular germ cell tumors (TGCTs) detailing the copy number of chromosomal regions and expression of 245 genes. An initial precursor stage, intratubular germ cell neoplasia (IGCN), is characterized by triploidization and an upregulation of KIT, ALPP, CCDN2, and ZNF354A, and a downregulation of CDKN2D. TGCT regularly have a series of chromosomal aberrations: a decrease in copy number at 4q21 approximately qter and 5q14 approximately qter; an increase at 7p21 approximately pter, 7q21 approximately q33, and 8q12 approximately q23 (especially high increase in seminoma); a decrease at 11p11 approximately p15 and 11q14 approximately q24; an increase at 12p11 approximately pter; a decrease at 13q14 approximately q31; an increase of 17q11 approximately q21 (only for nonseminoma); a decrease of 18q12 approximately qter; and an increase at 21q21 approximately qter, 22q11 approximately qter (only for seminoma), and Xq. Macroscopically overt TGCT is associated with a characteristic series of abnormalities in the retinoblastoma pathway including upregulation of cyclin D2 and p27 and downregulation of RB1 and the cyclin-dependent kinase inhibitors p16, p18, p19, and p21. TGCT thus has a synergistic pattern in gene expressions of the retinoblastoma pathway that is rare in other malignancies.

Molecular advances in genetic skin diseases

The genes for several genetic skin diseases have been identified in recent years. This development improves diagnostic capabilities and genetic counseling, and investigators can now turn to the molecular mechanisms involved in the pathogenesis of these diseases. The identification of the causative genes has led to the generation of mouse models for some genetic skin diseases. A study of the keratin 10 deficient mouse, a model for epidermolytic hyperkeratosis, and a mouse model for Bloom syndrome are reviewed in this article. Several studies also evaluate the relation between genotype and phenotype. In this article, the clinical findings and molecular advances in tuberous sclerosis complex, neurofibromatosis type 1, Bloom syndrome, epidermolytic hyperkeratosis, X-linked ichthyosis, Netherton syndrome, and Hermansky-Pudlak syndrome are reviewed.

Absence of the granular layer and keratohyalin define a morphologically distinct subset of individuals with ichthyosis vulgaris

The clinical diagnosis of ichthyosis vulgaris (IV) can be difficult. Abnormalities in the granular layer and the ultrastructure of keratohyalin granules (KHG) suggest that morphology may be helpful. To clarify morphologic findings in IV, 41 clinically affected individuals and 21 unaffected family members or age- and sex-matched controls were studied by light microscopy. In these, the granular layer was totally absent in approximately 50% of affected individuals, while present in all controls. Forty-seven individuals in the light microscopy group were also studied by electron microscopy. Keratohyalin granules were absent in all affected individuals lacking the granular layer by light microscopy. Clinical severity usually correlated with the lack of a granular layer and KHG. Absence of the granular layer was consistent in different anatomic sites and in serial biopsies taken over a 1-3-year period. In a subset of clinically affected, unrelated subjects with moderate to severe involvement, four out of 11 (36%) had similar findings. Keratinocytes cultured from affected individuals with no KHG expressed virtually no detectable profilaggrin protein in vitro. The data suggest that a subset of individuals with moderate to severe IV have a consistently absent granular layer and KHG. Absence of the granular layer and lack of KHG correlated almost perfectly; thus light microscopy offers a convenient means of identifying this subtype of IV. However, both morphologic types of IV were observed within single families. Therefore, the relationship between granular layer abnormalities and IV is complex and requires the study of more affected families. One interpretation of the data is that IV is a multigenic disorder in which one of the genes alters profilaggrin expression. We propose this clinical and histologic phenotype as useful for identifying the gene(s) involved and also for determining whether it represents a modifier or a major locus of the disorder.

Corneal manifestations of X-linked ichthyosis in two brothers

PURPOSE

To report the unusual manifestation of X-linked ichthyosis in two brothers.

METHODS

Leukocyte separation and sterylsulfatase assay are performed to show the deficiency of sterylsulfatase.

RESULTS

Two brothers presented in our clinic with cutaneous alterations consistent with X-linked ichthyosis. Ocular examination disclosed fine, flour-like, punctate, evenly, and diffusely distributed opacities of the posterior corneal stroma, close to Descemet membrane in both patients. In one patient, superficial, small, granular opacities were detected. They were gray in color and seemed to involve the epithelium and the subepithelial and anterior stromal layers. In both patients, the deficiency of sterylsulfatase could be shown and confirmed the diagnosis.

CONCLUSIONS

Flour-like opacities in the posterior stroma have been shown to be a common manifestation of X-linked ichthyosis. Though the underlying biochemical defect in X-linked ichthyosis has been discovered, the question of how these opacities develop is still a subject of debate. Subepithelial stromal keratopathies or epithelial irregularities are uncommon and are rarely described in the literature. The superficial corneal changes seen in one of our patients are unusual and are not similar to those reported by other authors.

The major inherited disorders of cornification. New advances in pathogenesis

This article provides a synopsis of the major (most common) inherited disorders of cornification. It also reviews the recent advances that have been made for each disorder and their practical applications.

A clinical and genetic study of X-linked recessive ichthyosis and contiguous gene defects

X-linked recessive ichthyosis (XLI) is caused by a deletion, or mutation, of the steroid sulphatase gene on the distal short arm of the X chromosome (Xp22.3). This region of the X chromosome is particularly susceptible to deletions. Such deletions can occasionally extend to involve neighbouring genes, causing a contiguous gene defect. Therefore, XLI may be associated with Kallmann's syndrome (KS), mental retardation, X-linked recessive chondrodysplasia punctata and short stature. We have reviewed 33 patients with XLI. Nine showed evidence of contiguous gene defects. A further four had neurological deficit sustained at the time of birth. This study highlights the importance of screening patients with X-linked recessive ichthyosis for neighbouring genetic disorders and, in particular, the early identification of KS, as delay in diagnosis may lead to infertility and osteoporosis. Parents should be warned about possible obstetric complications due to prolonged labour in future pregnancies.

Prenatal detection of X-linked ichthyosis by maternal serum screening for Down syndrome

Maternal serum unconjugated oestriol (uE3) was measured in 15,375 pregnancies during 2 years of second-trimester risk assessment for Down syndrome using biochemical markers. Very low levels of uE3 (< 0.1 MOM) were detected in 22 serum samples (0.14 per cent). Very low uE3 was associated with an adverse outcome in 13 pregnancies including fetal death and miscarriage (N = 11) anencephaly (N = 1), and Meckel-Gruber syndrome (N = 1). Dry scales on the skin appeared in the first year of life in four boys. From dermatological diagnosis, prenatal uE3 levels, and pedigree analysis, it is concluded that at least 5 in approximately 7500 male births in the study population are affected by steroid sulphatase deficiency, which is the biochemical defect in X-linked ichthyosis. Very low uE3 levels in the second trimester are indicative of this disease in pregnancies with normal ultrasound findings.

Epidermolytic hyperkeratosis: applied molecular genetics

Epidermolytic hyperkeratosis is an autosomal dominant ichthyosis characterized by blistering, especially at birth and during childhood, and hyperkeratosis. Epidermolytic hyperkeratosis presents striking clinical heterogeneity, particularly between families. Several avenues of research have implicated an abnormality of epidermal differentiation in the pathogenesis of this disease. In a three-generation family with 20 affected individuals, we tested a variety of candidate loci and identified linkage to the type II keratin region on chromosome 12. Further investigation revealed a mutation in the H1 subdomain of the keratin 1 gene as the cause of EHK in this family. Because keratin 10 is the co-expressed partner of keratin 1, it was not surprising when abnormalities in keratin 10 were found in other families with EHK. We have examined 52 patients from 21 families and have identified at least six clinical phenotypes. The most useful distinguishing feature was the presence or absence of severe hyperkeratosis of the palms and soles. We and others are continuing to search for and characterize mutations in keratin 1 and 10 in patients with epidermolytic hyperkeratosis. Correlation of the clinical disease types with the specific mutations should lead to a better understanding of the relationship between keratin structure and function in normal and diseased epidermis.

Testis cancer. Ichthyosis constitutes a significant risk factor

Testis cancer and ichthyosis are both relatively rare diseases. Hence the finding of six individuals with both these conditions in a small population with testicular cancer is highly conspicuous and indicates some kind of connection among such persons. Despite the identical clinical appearances of their ichthyoses, three of the ichthyotic subjects had no measurable activity of the enzyme, steroid sulfatase (STS) in leucocytes, a distinct characteristic of recessive X-linked ichthyosis (RXLI). However, the remaining three subjects had normal STS activity, a strong indicator of autosomal dominant ichthyosis (ADI). The STS activity in patients with testicular cancer who do not have ichthyosis (N = 30) was also within the normal range. The patients with testicular cancer with no skin disease had elevated serum levels of 4-androstenedione (4-AD), follicle stimulating hormone (FSH), and luteinizing hormone (LH) but had reduced levels of estrone and estrone sulfate. The other serum parameters measured did not significantly differ from normal levels. In essence, the hormone levels obtained for the patients with ichthyotic testicular cancer followed the same pattern, although their dehydroepiandrosterone sulfate (DHEAS) and estrone sulfate levels tended to be slightly higher than normal. However, no conspicuous aberrations in any of the parameters examined were observed, and why men with ichthyosis are at high risk for testicular cancer remains an unresolved issue.

A family with X-linked ichthyosis and hypogonadism

We describe the clinical, biochemical and ophthalmic findings in four closely related males with X-linked ichthyosis and hypogonadism. Recognition of this association is important for both paediatricians and paediatric dermatologists.

Ocular findings and skin histology in a group of patients with X-linked ichthyosis

We carried out ophthalmological examinations, and histopathological examinations of skin biopsies in 32 male patients affected by X-linked ichthyosis. We found corneal opacities in only five patients, and their presence was not related to the age of the patients. Skin histology revealed a reduction of the granular layer in nine cases, a finding previously thought to be typical of autosomal dominant ichthyosis vulgaris.

X-linked mental retardation associated with psoriasis: a new syndrome?

Four males, the sons of 2 sisters, apparently have a new syndrome of mental retardation, seizures and psoriasis. Due to the relationship between the affected males we propose the inheritance to be X-linked recessive although cosegregation of two separate disorders may be occurring. Psoriasis has never been reported as a monogenic disorder. Results of cytogenetic studies, including fra (X) and high-resolution prometaphase analysis, were negative. Steroid sulfatase activities of cultured fibroblasts from 2 surviving affected males were normal. The results of HLA typing of all available relatives did not indicate a strong association between the skin disorder and certain HLA antigens. A healthy sister, who may be heterozygous carrier of the mutant X chromosome, decided on termination of 3 successive pregnancies after prenatal male sex determinations. Her fourth pregnancy with a female fetus is ongoing.

Deletions of the steroid sulphatase gene in "classical" X-linked ichthyosis and in X-linked ichthyosis associated with Kallmann syndrome

We have studied 16 men, from 10 unrelated Italian families, affected by steroid suphatase (STS) deficiency, which is the basic defect of X-linked ichthyosis (XLI). The patients' clinical diagnoses were of either isolated ichthyosis or ichthyosis associated with Kallmann syndrome (KS) (hypogonadotropic hypogonadism and anosmia). DNA from patients and their relatives was analysed by Southern blotting followed by hydridization with an STS cDNA probe. None of the patients affected by either XLI or XLI/KS showed any hybridization signal, thus revealing a deletion in the STS gene. We suggest that a gene deletion may be the most common molecular defect involved in XLI and that the syndrome XLI/KS may be due to a deletion of both the STS and the KS loci.