Characteristic Morphologic Abnormality of Harlequin Ichthyosis Detected in Amniotic Fluid Cells

ABCA12 mutations and autosomal recessive congenital ichthyosis: A review of genotype/phenotype correlations and of pathogenetic conceptsa

“…In HI affected epidermis, several morphologic abnormalities including abnormal lamellar granules in the keratinocyte granular layer and a lack of extracellular lipid lamellae within the stratum corneum had been reported [Akiyama et al, 1994[Akiyama et al, , 1998Dale et al, 1990;Milner et al, 1992]. Lack of ABCA12 function subsequently leads to disruption of lamellar granule lipid transport in the upper keratinizing epidermal cells resulting in malformation of the intercellular lipid layers of the stratum corneum in HI (Fig.…”

“…Before the causative gene for HI was identified, prenatal diagnosis had been performed by fetal skin biopsy and electron microscopic observation during the later stages of pregnancies at 19-23 weeks estimated gestational age for more than 20 years [Akiyama et al, 1994[Akiyama et al, , 1999Blanchet-Bardon et al, 1983;Shimizu et al, 2005]. The late timing of prenatal testing was a heavy burden on the pregnant mothers.…”

Harlequin ichthyosis and other autosomal recessive congenital ichthyoses: The underlying genetic defects and pathomechanisms

“…Ultrastructurally, lamellar granule abnormalities are apparent in HI patient epidermis [35][36][37][38]. The cornified cell envelope appears to be normal in HI and major cornified cell envelope precursor proteins (involucrin, small proline-rich proteins 1 and 2, and loricrin) are normally distributed in the HI epidermis [39,40].…”

“…From these findings, HI and type 2 LI diseases are thought to be caused by a different pathomechanisms from malformations in cornified cell envelope. Several morphologic abnormalities, for example the abnormal lamellar granules in the granular layer keratinocytes and a lack of extracellular lipid lamellae in the stratum corneum, reflect the defective lipid transport via lamellar granules and the malformation of intercellular lipid layers in the stratum corneum in HI [35][36][37][38][39]. In type 2 LI, no distinct ultrastructural features have yet been reported.…”

Expecting the most unexpected – a harlequin baby! A case report and literature analysis

“…Harlequin ichthyosis (HI) -the most severe form of keratinizing disorders, often lethal in the neonatal period is characterized by a profound thickening of the keratin skin layer, a dense "armor"-like scale that covers the body, and contraction abnormalities of the eyes, ears, and mouth. Akiyama et al [21][22][23][24][25] report that mutations in ABCA12 caused defective lipid transport that significantly impacted normal development of the skin barrier. Lipid secretion was recovered after corrective ABCA12 gene transfer into patient keratinocytes.…”