Corneal manifestations of X-linked ichthyosis in two brothers

Ocular surface analysis in patients diagnosed with X-linked ichthyosis

Seven patients (14 eyes) diagnosed with X-linked ichthyosis were studied using the Schirmer test, biomicroscopy, tonometry, endothelial count, optical coherence tomography, Pentacam®, ocular surface analyser, and confocal microscopy. The mean age was 33.83±20.17 years (range: 7-64 years). The most frequent findings in biomicroscopy were Meibomian glands dysfunction (83.3%) and stromal corneal opacities (33%). The tear break-up time was found shortened in 25% of the eyes. Confocal microscopy (both eyes) revealed activated keratocytes with hyper-reflective particles inside them in the anterior stroma and outside them in the posterior stroma. It is believed that the inclusion of the use of confocal microscopy will help in a better understanding of the corneal pathology associated with ichthyosis X, as well as new characteristics of these patients.

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

These guidelines for the management of congenital ichthyoses have been developed by a multidisciplinary group of European experts following a systematic review of the current literature, an expert conference held in Toulouse in 2016, and a consensus on the discussions. These guidelines summarize evidence and expert-based recommendations and intend to help clinicians with the management of these rare and often complex diseases. These guidelines comprise two sections. This is part two, covering the management of complications and the particularities of some forms of congenital ichthyosis.

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.

Ocular manifestations of genetic skin disorders

Genetic skin diseases, or genodermatoses, often have extracutaneous manifestations. Ocular manifestations in particular can have significant clinical implications, like blindness. Other manifestations, such as the corneal opacities that occur in X-linked ichthyosis, are asymptomatic but characteristic of a particular genodermatosis. Ophthalmologic examination can aid in diagnosis when characteristic findings are seen. The genodermatoses with ocular manifestations will be reviewed, but neurocutaneous, syndromes, genetic pigmentary disorders, and genetic metabolic diseases are not included because they are covered elsewhere in this issue.

X linked recessive ichthyosis: Current concepts

In the present review, we describe the most important aspects of the X-linked ichthyosis (XLI) and make a compilation of the some historic details of the disease. The aim of the present study is an update of the XLI. Historical, clinical, epidemiological, and molecular aspects are described through the text. Recessive XLI is a relatively common genodermatosis affecting different ethnic groups. With a high spectrum of the clinical manifestations due to environmental factors, the disease has a genetic heterogeneity that goes from a point mutation to a large deletion involving several genes to produce a contiguous gene syndrome. Most XLI patients harbor complete STS gene deletion and flanked sequences; seven intragenic deletions and 14 point mutations with a complete loss of the steroid sulfatase activity have been reported worldwide. In this study, we review current knowledge about the disease.

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.

X-linked ichthyosis: an oculocutaneous genodermatosis

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.