Clinical, light and electron microscopic features of recessive congenital ichthyosis type I

Abstract

Based on electron microscopic features, recessive congenital ichthyoses have recently been divided into four subgroups designated ichthyosis congenita (IC) types I, II, III and IV. Type II is characterized by cholesterol clefts in the horny cells, type III by perinuclear elongated membranes in the granular and horny cells, and type IV by masses of lipid membranes in granular and horny cells. Clear electron microscopic criteria for type I are lacking, although the presence of lipid droplets in the horny cells has been suggested as a criterion. In the present study we included ichthyosis patients with (i) recessive inheritance, (ii) erythrodermic fine scaling, (iii) lack of fine structural markers of IC types II-IV. Patients with ichthyotic syndromes were excluded. The case material consisted of 21 patients from 14 families. Eight were collodion babies at birth, but three were normal. Nine had ectropion, the flexures were affected in 12, and the palms and soles were thickened in all but one patient. On electron microscopy lipid vacuoles in the horny cells were common, but were absent in four patients. Changes in other lipid-related structures, including keratinosomes, were common. We conclude that currently type I can be diagnosed only by excluding the other types of ichthyosis. Clinically, IC type I corresponds to classical non-bullous congenital ichthyosiform erythroderma, but there is marked heterogeneity among affected individuals.

Development of ichthyosiform skin compensates for defective permeability barrier function in mice lacking transglutaminase 1

“…In keeping with our finding, the characteristic abnormal granules have also been recently documented in an adult LI patient with a TGase 1 mutation (45). Vacuoles or lipid droplets reported in IC type I and in some cases of IC type II seem to correspond to vacuoles seen in the cornified cells of the mature TGase 1 -/-mouse skin (14)(15)(16). The origin of those vacuoles is unknown, but some are fused with remnants of lamellar granules in the SC, suggesting that they are related to lipid metabolism.…”

Revised nomenclature and classification of inherited ichthyoses: Results of the First Ichthyosis Consensus Conference in Sorèze 2009

“…160 The ultrastructural features of the so-called EM classification described by the Heidelberg group are based on a glutaraldehyde fixation of the skin biopsy specimen. [206][207][208][209][210] With this technique polygonal clefts in the SC can be observed as an ultrastructural key feature of TGase-1 deficiency, 211 aberrant vesicular structures may indicate NIPAL4 (;ICHTHYIN ) mutations in ARCI, 33 and trilamellar membrane aggregations in the SC and SG (EM type IV) are pathognomonic for ichthyosis prematurity syndrome. 89 Detachment of the SC from the SG with asymmetric cleavage of corneodesmosomes is a specific feature of NS.…”

Clinical and morphological correlations for transglutaminase 1 gene mutations in autosomal recessive congenital ichthyosis

“…The most common electron-microscopic markers include lipid droplets or rings and lamellar structures, but the markers are not as specific as the findings in other IC types ( Figure 1a). 12 …”