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X-linked recessive ichthyosis (XLI) is clinically characterized by dark brown, widespread dryness with polygonal scales. We describe the identification of STS and PUDP deletions using targeted panel sequencing combined with copy-number variation (CNV) analysis in XLI. A 9-month-old infant was admitted for genetic counseling. Since the second day after birth, the infant's skin tended to be dry and polygonal scales had accumulated over the abdomen and upper extremities. The infant's maternal uncle and brother (who had also exhibited similar skin symptoms from birth) presented with polygonal scales on their trunks. CNV analysis revealed a hemizygous deletion spanning 719.3 Kb on chromosome Xp22 (chrX:7,108,996-7,828,312), which included a segment of the STS gene and exhibited a Z ratio of -2 in the proband. Multiplex ligation-dependent probe amplification (MLPA) confirmed this interstitial Xp22.31 deletion. Our report underscores the importance of implementing CNV screening techniques, including sequencing data analysis and gene dosage assays such as MLPA, to detect substantial deletions that encompass the STS gene region of Xq22 in individuals suspected of having XLI.

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.

Purpose: To investigate the presence of pre-Descemet corneal dystrophy (PDCD) in association with X-linked ichthyosis (XLI) in an 11-year-old boy using multimodal imaging and genetic analysis., Methods: Corneal opacities were examined and imaged with slit-lamp biomicroscopy, anterior segment optical coherence tomography, noncontact specular microscopy, and in vivo confocal microscopy. Cytogenomic array analysis was performed using genomic DNA isolated from the patient., Results: Corneal opacities characteristic of PDCD located in the posterior corneal stroma just anterior to Descemet membrane were identified by slit-lamp biomicroscopy. A pre-Descemet hyper-reflective line, consistent with these opacities, was seen with anterior segment optical coherence tomography. Scheimpflug tomography revealed a bimodal peak light scattering. In vivo confocal microscopy findings were unremarkable. Copy number analysis identified a 4389 kbp hemizygous deletion on the X chromosome (chr. X: 6,540,898-8,167,604), resulting in the deletion of 4 genes, including the known locus of XLI, the STS gene., Conclusions: This report demonstrates that PDCD-associated XLI may present in children and that the diagnosis may be confirmed through multimodal imaging in conjunction with genetic analysis.

Background: X-linked ichthyosis (XLI) is the second most common type of ichthyosis, which is characterized by wide and symmetric distribution of adherent, dry, and polygonal scales on the skin. Steroid sulfatase (STS) gene, which is located at chromosome Xp22.31, has been identified as the pathogenic gene of XLI., Methods: In this study, chromosome karyotype analysis, bacterial artificial chromosomes-on-Beads™ (BoBs) assay, fluorescence in situ hybridization (FISH), and single nucleotide polymorphism array (SNP-array) were employed for the prenatal diagnoses in three pregnant women with high-risk serological screening results and a pregnant woman with mental retardation., Results: STS deletion was identified at chromosome Xp22.31 in all four fetuses. Postnatal follow-up confirmed the diagnosis of ichthyosis in two male fetuses and revealed normal dermatological manifestations in other two female fetuses carrying ichthyosis., Conclusion: The results of the present study demonstrate that a combination of karyotypying, prenatal BoBs, FISH, and SNP-array may avoid the missed detection of common microdeletions and ensure the accuracy of the detection results, which provides a feasible tool for the reliable etiological diagnosis and better genetic counseling of XLI., (© 2020 The Authors. Journal of Clinical Laboratory Analysis Published by Wiley Periodicals, Inc.)

Objective: With the replacement of karyotyping by chromosomal microarray (CMA) in invasive prenatal diagnosis, new challenges have arisen. By building a national database, we standardize the classification and reporting of prenatally detected copy number variants (CNVs) across Belgian genetic centers. This database, which will link genetic and ultrasound findings with postnatal development, forms a unique resource to investigate the pathogenicity of variants of uncertain significance and to refine the phenotypic spectrum of pathogenic and susceptibility CNVs., Methods: The Belgian MicroArray Prenatal (BEMAPRE) consortium is a collaboration of all genetic centers in Belgium. We collected data from all invasive prenatal procedures performed between May 2013 and July 2016., Results: In this three-year period, 13 266 prenatal CMAs were performed. By national agreement, a limited number of susceptibility CNVs and no variants of uncertain significance were reported. Added values for using CMA versus conventional karyotyping were 1.8% in the general invasive population and 2.7% in cases with an ultrasound anomaly. Of the reported CNVs, 31.5% would have remained undetected with non-invasive prenatal test as the first-tier test., Conclusion: The establishment of a national database for prenatal CNV data allows for a uniform reporting policy and the investigation of the prenatal and postnatal genotype-phenotype correlation., (© 2018 John Wiley & Sons, Ltd.)

Placental steroid sulphatase deficiency (SSD) is an X-linked inborn error of metabolism. Congenital X-linked ichthyosis (XLI) is a genetic disorder of keratinisation caused by steroid sulphatase (STS) deficiency, which results in a scaling skin condition in male infants shortly after birth. It may be associated with failed induction of labor and prolonged labor leading to cesarean delivery due to 'cervical dystocia'. We present two cases of congenital ichthyosis. Thorough counselling of women with a previously affected pregnancy during the antenatal period should include discussion about mode of delivery and a critical review of the complexities of prenatal diagnosis in this condition. We propose a clinical management pathway to offer women with a previous pregnancy affected by this rare condition. SIMILAR CASES PUBLISHED: Less than 50 cases reported.

Background: X-linked recessive ichthyosis (XLI) is a relatively common type of ichthyosis caused by a deficiency in the steroid sulfatase (STS) enzyme. It is the only type of ichthyosis that can be both syndromic and nonsyndromic. Typical clinical features include dark-brown scale of variable size favouring the extensor surfaces of the extremities., Objectives: To characterize clinically nonsyndromic XLI, with a particular focus on extracutaneous manifestations., Methods: This was a multicentre retrospective review of clinical findings from a case series of patients with a clinical and genetic diagnosis of XLI., Results: We identified 30 patients with XLI belonging to 25 different families carrying a deletion in the STS locus. All patients had dark scales of variable size on the extensor surfaces of the extremities. Lack of flexural involvement and pruritus were common but inconsistent findings, whereas palmoplantar hyperlinearity was absent in all but one patient. A history of orchiopexy was present in 10% and thus was more common than expected vs. the general population (3%). Neurological disorders including epilepsy (13%) and attention deficit hyperactivity disorder (ADHD; 30%) were over-represented in patients with XLI., Conclusions: This was a retrospective study with a limited number of patients. In the absence of confirmatory genetic testing and family history of the disease, dark-brown scale of the extensor surfaces and the absence of palmoplantar hyperlinearity appear to be the most reliable clinical findings supporting a diagnosis of XLI. Dermatologists should be aware of the high prevalence of ADHD and epilepsy in patients with nonsyndromic XLI., (© 2018 British Association of Dermatologists.)

X-linked ichthyosis (XLI) is a metabolic disease with steroid sulfatase deficiency and often occurs at birth or shortly after birth. The encoding gene of steroid sulfatase, STS, is located on the short arm of the X chromosome, and STS deletion or mutation can lead to the development of this disease. This study collected the data on the clinical phenotype from a family, and the proband, a boy aged 11 years with full-term vaginal delivery, had dry and rough skin and black-brown scaly patches, mainly in the abdomen and extensor aspect of extremities. Peripheral blood samples were collected from each family member and DNA was extracted. Multiplex ligation-dependent probe amplification (MLPA) was used to measure the copy number of STS on the X chromosome. Whole-genome microarray was used to determine the size of the segment with microdeletion in the X chromosome. MLPA was then used for prenatal diagnosis for the mother of the proband. The results revealed that the proband and another two male patients had hemizygotes in STS deletion. Gene microarray identified a rare deletion with a size of 1.6 Mb at Xp22.31 (chrX: 6,516,735-8,131,442). Two female family members were found to be carriers. Prenatal diagnosis showed that the fetus carried by the proband's mother was a carrier of this microdeletion. This study showed STS gene deletion in this family of XLI, which causes the unique skin lesions of XLI. MLPA is a convenient and reliable technique for the molecular and prenatal diagnosis of XLI.

Background: X-linked ichthyosis (XLI) is a rare dermatological condition arising from deficiency for the enzyme steroid sulfatase (STS). Preliminary evidence in boys with XLI, and animal model studies, suggests that individuals lacking STS are at increased risk of developmental disorders and associated traits. However, the behavioural profile of children with XLI is poorly-characterised, and the behavioural profile of adults with XLI has not yet been documented at all., Materials and Methods: Using an online survey, advertised worldwide, we collected detailed self- or parent-reported information on behaviour in adult (n = 58) and younger (≤18yrs, n = 24) males with XLI for comparison to data from their non-affected brothers, and age/gender-matched previously-published normative data. The survey comprised demographic and background information (including any prior clinical diagnoses) and validated questionnaires assaying phenotypes of particular interest (Adult ADHD Self-Report Scale v1.1, Barrett Impulsiveness Scale-11, adult and adolescent Autism Quotient, Kessler Psychological Distress Scales, and Disruptive Behaviour Disorder Rating Scale)., Results: Individuals with XLI generally exhibited normal sensory function. Boys with XLI were at increased risk of developmental disorder, whilst adults with the condition were at increased risk of both developmental and mood disorders. Both adult and younger XLI groups scored significantly more highly than male general population norms on measures of inattention, impulsivity, autism-related traits, psychological distress and disruptive behavioural traits., Conclusions: These findings indicate that both adult and younger males with XLI exhibit personality profiles that are distinct from those of males within the general population, and suggest that individuals with XLI may be at heightened risk of psychopathology. The data are consistent with the notion that STS is important in neurodevelopment and ongoing brain function, and with previous work suggesting high rates of developmental disorders in boys with XLI. Our results suggest that individuals with XLI may require medical care from multidisciplinary teams, and should help to inform genetic counselling for the condition., Competing Interests: The authors have declared that no competing interests exist.

In this study, we report the case of a 12-year-old male with X-linked ichthyosis (XLI) in association with glomerular sclerosis, and our investigation into the deletion pattern of the STS gene and the flanking regions in DNA samples of family members. We observed no features typical of renal osteodystrophy or rickets, with the exception of short stature, in the three afffected male family members. Audiometry, visual acuity and olfactory sensation were normal. By performing PCR analysis of the steroid sulfatase (STS) gene and flanking regions on our patients, we discovered a complete deletion that involved the entire region from DXS1139 to DXF22S1. Further studies are required to determine whether the STS gene or the co-deleted flanking sequences are the cause of renal disease associated with XLI.

Unlabelled: Nephrotic syndrome associated with X-linked recessive ichthyosis due to steroid sulfatase deficiency has rarely been reported in English literature. We describe a 4 and a half-year-old boy presenting with steroid-resistant nephrotic syndrome (SRNS) with an underlying ichthyotic skin present since birth. Renal biopsy revealed minimal change disease. As many of the male members of the family also showed similar skin manifestations, genetic analysis was done on the patient, which revealed deletion of the steroid sulfatase (STS) gene spanning both the 3' as well as the 5'ends. The patient was thus diagnosed with SRNS associated with X-linked recessive ichthyosis. He was started on cyclosporine regimen, and remission was achieved in 5 weeks. We speculate that the deficiency of STS resulting in increased cholesterol sulfate accumulation interferes with the integrity of adherens junctions present between glomerular epithelial cells of the slit diaphragm, and this results in proteinuria and nephrotic syndrome. The nephrotic syndrome remitted with a calcineurin inhibitor medication., Conclusion: We suggest that the deficiency of STS is another one in an increasing list of genetic causes of podocytopathy and nephrotic syndrome. Remission of proteinuria in such a case may be achieved with immunosuppressive medication.

X-linked ichthyosis (XLI) is an X-linked recessive disorder of cutaneous keratinization with possible extracutaneous manifestations. It was first described as a distinct type of ichthyosis in 1965. XLI is caused by a deficiency in steroid sulfatase activity, which results in abnormal desquamation and a retention hyperkeratosis. XLI is usually evident during the first few weeks of life as polygonal, loosely adherent translucent scales in a generalized distribution that desquamate widely. These are quickly replaced by large, dark brown, tightly adherent scales occurring primarily symmetrically on the extensor surfaces and the side of the trunk. In addition, extracutaneous manifestations such as corneal opacities, cryptorchidism, and abnormalities related to contiguous gene syndromes may be observed. Diagnosis of XLI is usually made clinically, as the histopathology is nonspecific, but confirmation may be obtained through either biochemical or genetic analysis. Treatment should focus on cutaneous hydration, lubrication, and keratolysis and includes topical moisturizers and topical retinoids., (Copyright 2009 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Objective: To ascertain all prenatally diagnosed cases of Steroid Sulfatase (STS) deficiency in British Columbia between August 2002 and July 2007 to determine the incidence of this condition, the clinical and laboratory findings, and the risk of a contiguous gene deletion syndrome., Methods: We reviewed the medical records of these patients to obtain detailed information about the maternal serum screening results, family history, investigations performed, and outcome of the pregnancy., Results: Thirty pregnant patients were found to have a male fetus/infant with STS deficiency, giving a minimal estimated incidence of this condition of approximately 1 in 1513 males. In twenty nine cases, this condition was isolated. One patient was found to have a contiguous gene deletion syndrome. In cases of sporadic STS deficiency diagnosed prenatally, the frequency of contiguous gene deletion syndrome in this study was 1 out of 12 (8.3%)., Conclusion: The clinical, cytogenetic and molecular data on this series of prenatally diagnosed cases of STS deficiency indicates that this is a common condition and in cases with no family history, the risk of contiguous gene deletion syndrome is significant, and warrants additional molecular genetic investigations of the mother and/or fetus.

Objective: To analyze the pathogenic mutation of an X-linked ichthyosis (XLI) family, and identify the genetic diagnosis of three probable female carriers in this family. To evaluate the availability of different detect methods for steroid sulfatase (STS) gene mutation., Methods: Peripheral blood samples were collected from the family, including the proband, proband's mother, younger sister, and younger female cousin, and 10 males and 10 females as controls. Ordinary PCR was used to detect whether there was STS gene deletion in the male proband. Then, multiplex quantitative fluorescent PCR (QF-PCR) was used to detect the STS gene in the proband and his 3 female family members. Fluorescence in situ hybridization (FISH) was used to authenticate the results of multiplex QF-PCR method., Results: No amplified product of the exons 1-10 of STS gene deletion was detected by ordinary PCR in the proband. The proband's mother was diagnosed as a carrier, but his sister and cousin were diagnosed as normal females by multiplex QF-PCR. FISH confirmed the results of multiplex QF-PCR., Conclusion: Both multiplex QF-PCR and FISH are effective to detect the complete deletion mutation of STS gene and identify the female carrier, and multiplex QF-PCR is more convenient and automatic compared with FISH.

The annual incidence of child abuse was estimated to be 2.8 million by the national incidence study conducted in the USA in 1993, which is a two-fold increase compared to 1986. Awareness of child abuse has been increasing since the 1960s. Although most victims of child abuse present with cutaneous lesions, many genuine skin diseases may appear as non-accidental injuries which, if not recognized, may lead to misdiagnosis of child abuse. Here, we review the most common cutaneous mimickers of child abuse in order to increase awareness of these disorders and reduce erroneous diagnosis of child abuse.

We describe a 10-year-old boy with X-linked ichthyosis, Kallmann Syndrome and unilateral renal agenesis who presented with nephrotic syndrome. DNA analysis revealed deletion of the Steroid Sulfatase (STS) gene. STS deficiency in X-linked ichthyosis leads to cholesterol sulfate accumulation, which induces transglutaminase-1 dysfunction. Since the slit diaphragm of the glomerular epithelial cell is a modified adherens junction, the accumulation of cholesterol sulfate could interfere with the normal slit diaphragm function of the glomerular visceral epithelial cell, resulting in nephrotic range proteinuria. The child went into remission on oral prednisolone.

This report presents a case of steroid sulfatase deficiency with bilateral periventricular nodular heterotopia. A 13-year-old male was diagnosed as having steroid sulfatase deficiency because steroid sulfatase activity was not detected in his leukocytes. In deoxyribonucleic acid studies, steroid sulfatase locus and adjacent loci were found to be deleted in his deoxyribonucleic acid. Cranial magnetic resonance imaging revealed periventricular nodular heterotopia, disclosing an irregular contour of the lateral walls of the lateral ventricles due to small nodular masses that were isointense as to the gray matter. In steroid sulfatase deficiency patients, bilateral periventricular nodular heterotopia must be considered.

Objective: The aim of this study is to find out the association of atopic dermatitis and other atopic features with primary hereditary ichthyosis (PHI) among Saudi patients in King Fahd Hospital of the University, Al-Khobar, Kingdom of Saudi Arabia., Methods: From the out-patient Department of Dermatology logbooks, all Saudi patients with clinically and histopathologically confirmed PHI seen between January 1990 and December 1995 were included in this study. Clinical findings regarding the atopic manifestations of PHI were extracted into data collection forms and computer-analyzed, using Statistical Package for Social Sciences., Results: Over a 6-year study period, 10,455 new patients were seen in our Dermatology Clinics. Of these, 61 had PHI, there were 37 males and 24 females with a ratio of 1.5:1. Atopic dermatitis (AD), diagnosed according to Hanifin and Rajka criteria, was found in 7 (11.5%) patients of PHI; 5 of which were ichthyosis vulgaris and 2 with x-linked recessive ichthyosis. Isolated features of atopy were observed in the form of pruritus 49 (80%), elevated immunoglobulin E 27 (44.3%), dandruff 24 (39%), keratosis pilaris (KP) 15 (25%) and asthma 3 (5%)., Conclusion: In the present study, there was an 11.5% association between AD and PHI. However, isolated features of atopy were found in PHI in variable proportions ranging from 5-80%.

Purpose: We describe two brothers with generalized epilepsy, attention deficits, congenital ichthyosis, and Leri-Weill dyschondrosteosis who harbor an unusual Xp; Yq translocation chromosome, resulting in a novel contiguous gene syndrome because of deletion of genes from the distal short arm of the X chromosome., Methods: Physical examination, neuropsychologic testing, EEG, and neuroimaging studies were performed. Because of their unusual phenotype, karyotyping, fluorescence in situ hybridization, and further molecular analyses were carried out to refine the break points of the underlying unbalanced sex chromosome rearrangement., Results: The subjects had generalized epilepsy, X-linked ichthyosis, Madelung deformities, mesomelia, normal intelligence, and attention deficits. The brothers' karyotype was unbalanced; they inherited a maternal derivative X chromosome. Deleted distal Xp genes included short-stature homeobox on the X chromosome (SHOX), aryl sulfatase E (ARSE), variably charged X-chromosome mRNA gene A (VCX-A), and steroid sulfatase (STS). The final karyotype was 46,Y,der(X)t(X; Y)(p22.3; q11.2).ish der(X) (DXZ1+, KAL+, STS-, SHOX-) mat., Conclusions: Loss of distal contiguous Xp genes resulted in a syndrome comprising bony deformities, ichthyosis, attention problems, and generalized epilepsy. Candidate epilepsy genes within the deleted segment, such as ASMT, a gene involved in the final synthesis of melatonin, are discussed. Cytogenetic analyses should be included in the clinical evaluation of patients with generalized epilepsy and complex phenotypes.

X-linked ichthyosis (XLI) is a relatively common genetic disorder that occurs in about one in every 2000-6000 male births. Clinically, XLI is characterized by a generalized scaling of the skin, with large, polygonal, dark brown scale, and more prominent on the extensor aspects of the limbs. It is known that an undetectable maternal serum, unconjugated estriol, associated with placental steroid sulfatase (STS) deficiency, may be the cause of cause of XLI. In most case, STS deficiency is caused by a complete or partial deletion of the STS gene mapped on chromosome Xp22.3. We describe here the prenatal detection of a male fetus affected with STS deficiency as a result of an undetectable unconjugated estriol in the second-trimester maternal serum screening. Microdeletion of the STS gene was confirmed by fluorescence in situ hybridization analysis of cultured amniotic fluid.

Background: X-linked recessive ichthyosis (XRI) is a relatively common genetic disorder of keratinization caused by deficiency in steroid sulfatase (STS) activity. STS appears to play an important role in testosterone metabolism. Therefore it has been discussed that the presence of normally functioning STS may be a presupposition for the development of androgenetic alopecia (AGA)., Methods: Patients with the diagnosis of XRI were sent questionnaires., Results and Conclusions: We reviewed 26 cases with XRI and noticed 11 patients with AGA in an advanced stage. The existence of two pathways for the steroid biosynthesis may be the explanation for a compensatory mechanism in XRI males. The Delta5 pathway depends on steroid sulfate activity, whereas the working Delta4 pathway produces AGA in XRI males., (Copyright 2003 S. Karger AG, Basel)

Ichthyosis follicularis (IF) is a very rare neurocutaneous, X-linked recessive condition affecting the skin, hair, eyes, and central nervous system (CNS). This report describes a child with facial dysmorphism, mental retardation, psychomotor delay, congenital alopecia of the scalp, eyebrows, and eyelashes, and extensive spiny follicular papules. A skin biopsy specimen showed the characteristic absence of sebaceous glands. We also reviewed the literature on this very rare entity. Additional findings observed in our patient, including hepatosplenomegaly, undescended testicles, and ptosis, have not been reported before.

The IFAP syndrome is characterized by the congenital onset of ichthyosis follicularis, absence of hair, and photophobia. A limited number of patients with the disorder have been described, and X-linked recessive inheritance has been proposed. Two unrelated female patients with a complete IFAP syndrome are reported. Both patients show a diffuse distribution of the disorder without linear arrangement. Because the suggested X-linked recessive pattern of inheritance is unlikely in these patients, a different way of transmission or, alternatively, genetic heterogeneity of the disorder has to be considered.

Ichthyosis follicularis, congenital alopecia, and photophobia are typical features of a rare X-linked recessive disorder termed ichthyosis follicularis with atrichia and photophobia syndrome. A 3-year-old male with these findings and severe growth failure, mental retardation, generalized seizures, vascularizing keratitis, nail anomalies, inguinal hernia, and a normal chromosome constitution is presented. Two maternal male relatives were affected by the same condition. Magnetic resonance imaging revealed corpus callosum hypoplasia not described at present. Syndromes with alopecia, seizures, and mental retardation are analyzed on the basis of genetic and clinical results.

Background and Objective: The clinical differentiation of the hereditary ichthyosis forms is difficult and without laboratory markers hardly possible. Serum lipoprotein electrophoresis is one tool for detecting patients with recessive X-linked ichthyosis (XRI). Compared to controls, XRI patients show elevated electrophoretic mobilities of low density (LDL) and very low density lipoproteins (VLDL). This change in pattern is only partially explained by the increased LDL cholesterin sulfate concentration and is the subject of this study., Patients/methods: Patients suffering from XRI and ichthyosis vulgaris, healthy controls. SDS-PAGE-electrophoresis and isoelectric focusing for detection of XRI-associated variations in apolipoproteins apo B-100, apo C-III and apo E., Results: XRI-associated apolipoprotein variants were not found. In contrast to the literature, an increased electrophoretic mobility was also observed for HDL (high density lipoproteins) from XRI patients., Conclusions: The underlying cause of the increased electrophoretic mobility of VLDL and HDL in XRI patients remains unclear. Future studies should investigate other apolipoproteins and verify the cholesterin sulfate concentrations reported for VLDL and HDL from XRI patients.

X-linked ichthyosis is a genetic disorder of keratinization characterized by a generalized desquamation of large, adherent, dark brown scales. Extracutaneous manifestations include corneal opacity and cryptorchidism. Since 1978 it has been known that a deficit in steroid sulphatase enzyme (STS) is responsible for the abnormal cutaneous scaling, although the exact physiological mechanism remains uncertain. The STS gene has been mapped to the distal part of the short arm of the X chromosome. Interestingly, this region escapes X chromosome inactivation and has the highest ratio of chromosomal deletions among all genetic disorders, complete deletions having been found in up to 90% of patients. Diagnosis of patients with X-linked ichthyosis and female carriers is based on biochemical and genetic analysis. The latter currently seems to be the most accurate method in the majority of cases.

X-linked ichthyosis is an inherited disease with dark, regular and adherent scales as clinical characteristics. It is caused by a deficiency of the steroid sulphatase enzyme. Steroid sulphatase assay is a relative easy tool that enables correct diagnosis of X-linked ichthyosis patients and carriers. A large number of X-linked ichthyosis patients correspond to non-familial cases that seem to represent de novo mutations. In this study, we examined the X-linked ichthyosis carrier state of the mothers of 42 non-familial cases to determine whether their children corresponded to de novo mutations. To classify patients and carriers, a steroid sulphatase assay was performed in leukocytes using 7-[3H]-dehydroepiandrosterone sulphate as substrate. In 36 mothers (85%) we found steroid sulphatase activity compatible with the carrier state of X-linked ichthyosis. This data suggest that most of the mothers of these patients present the primary gene defect, excluding de novo mutations in the patients.

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.

We analyzed the steroid sulfatase (STS) gene in nine Japanese patients with X-linked ichthyosis (XLI) by a polymerase chain reaction technique and subsequent DNA sequencing. Eight of nine patients showed complete deletion of the STS gene. In a patient of XLI exhibiting a normal amplifying pattern with predicted sizes of the STS gene, a novel mutation was found resulting in the appearance of a stop codon in exon 7 of the STS gene. This suggests that exon 7 or an area in its downstream region is important for STS activity.

X-linked ichthyosis is an inherited skin disorder caused by deficiency of steroid sulfatase activity. We studied the possibility of diagnosing the defect in patients and carriers by using polymerase chain reaction (PCR) and high-performance liquid chromatography (HPLC). We chose the usual PCR procedure of 25 temperature cycles. PCR products were resolved by HPLC and quantified by measurement of absorbance at 260 nm. The optimal amount of DNA template was 50 ng using either steroid sulfatase (STS) or beta-globin (internal control) primer. The results show that the amount of STS in ichthyosis patients was null. The amount of STS DNA in mothers of patients was half of that in normal females. By this HPLC-PCR method we will able to diagnose not only ichthyosis patients but also carriers before birth.