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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.What's already known about this topic?Various symptomatic treatment options exist for congenital ichthyoses, but there are no European guidelines.What does this study add?These European guidelines for the management of congenital ichthyosis may help to improve outcomes and quality of life for patients.Linked Comment: Akiyama. Br J Dermatol 2019; 180:449-450. Plain language summary available online

Porokeratotic eccrine ostial and dermal duct nevus is a rare hamartomatous malformation, histologically characterized by cornoid lamellae overlying dilated eccrine ostia. The nevus most commonly presents in the form of multiple filiform keratotic spines in a linear arrangement, usually on the distal extremities (1). Porokeratotic eccrine and hair follicle nevus is thought to be a variant of porokeratotic eccrine ostial and dermal duct nevus that additionally involves hair follicle infundibula. We report a case of widespread Porokeratotic eccrine and hair follicle nevus that developed in a 15-year-old woman with keratitis-ichthyosis-deafness syndrome.

In this issue Caceres-Rios et al present an exhaustive review of the uncommon but clinically distinctive KID (keratitis, ichthyosis, deafness) syndrome and propose, on the basis of their analysis of the clinical phenotype, a change of name to KED (keratodermatous ectodermal dysplasia) syndrome. Implicit in the proposed name is a recategorization of KID syndrome as an ectodermal dysplasia. Before we actively or passively jump on the namechanging bandwagon and restructure our classification schemes, it seems reasonable to consider the implications of the proposed revision. The authors find the cutaneous phenotype inconsistent with disorders classified under the umbrella of ichthyosis because scaling is not the main clinical feature, and prefer to describe the typical changes as an erythrokeratoderma. Although they offer no definition, the term erythrokeratoderma is used in a context that seems to denote hyperkeratosis without prominent scaling, and with underlying erythema. Since ichthyoses are also characterized by hyperkeratosis, often in conjunction with erythema, the essence of the difference seems to boil down to whether visible scale is present or not. Without debating whether or not the fixed verrucous plaques so typical of KID syndrome could be considered nonscaling, is it legitimate to limit the ichthyosis appellation only to those generalized hyperkeratotic disorders that also display prominent scale? Are hyperkeratosis and scaliness reliably distinguishable from a clinical point of view? Don't they overlap at both the gross and microscopic levels?

BACKGROUND: Goat kids with floppy kid syndrome have metabolic acidosis, muscle weakness, and depression but no dehydration. HYPOTHESIS: D-Lactate is the major component of acidemia in goat kids with floppy kid syndrome. ANIMALS: Fifty-five goat kids with floppy kid syndrome (group F) and 35 clinically healthy goat kids (group C). METHODS: Clinical, biochemical, microbiologic, virologic, parasitologic, and pathologic examinations. RESULTS: The animals in group F had a blood pH of 7.13 +/- 0.11 and a base excess of -17.8 +/- 3.8 mM, which were both lower than the values in the control animals (pH, 7.32 +/- 0.31; base excess, -0.1 +/- 2.7 mM; P < .001). Floppy kids had a significantly larger anion gap than healthy kids (31.2 +/- 3.7 versus 21.5 +/- 8.5 mM; P < .001). The concentration of L-lactate was lower in floppy kids than in healthy kids (0.67 +/- 0.49 versus 1.60 +/- 1.02 mM), but the concentration of D-lactate was higher in floppy kids (7.43 +/- 2.71 versus 0.26 +/- 0.24 mM; P < .001). Intravenous and oral administration of sodium bicarbonate in floppy kids resulted in a significant increase in blood pH and base excess and a decrease in the anion gap (P < .001). In addition, the concentration of L-lactate increased (P = .039). CONCLUSIONS AND CLINICAL IMPORTANCE: Metabolic acidosis in goat kids with floppy kid syndrome is caused by an increase in the plasma concentration of D-lactate.

Zusammenfassung Hintergrund: Das „Keratitis-Ichthyosis-Deafness”-Syndrom (KID-Syndrom) ist eine sehr seltene genetisch bedingte Krankheit, die autosomal dominant vererbt wird, wobei vielen Fallen eine Neumutation zugrunde liegt. Als Ursache fur die Erkrankung wurden Mutationen im Gen GJB2, das Connexin 26 kodiert, gefunden. Patienten und Methodik: Wir haben bei zwei Patienten mit KID-Syndrom den klinischen Verlauf untersucht, sowie DNA aus dem peripheren Blut extrahiert. Ergebnisse: Beide Patienten zeigten eine Connexin-26-Mutation mit unterschiedlichem klinischen Verlauf. Schlusfolgerung: Bei beiden Patienten wurden zwei verschiedene heterozygote Connexin-26-Mutationen nachgewiesen, die sich in einem unterschiedlichen Verlauf manifestierten. Summary Background: Keratitis-ichthyosis-deafness syndrome (KID syndrome) is an extremely rare disorder. Inheritance is autosomal dominant but many cases occur sporadically following a spontaneous mutation. The cause of KID syndrome are missense mutations of the gene GJB2, encoding connexin 26. Patients and Methods: We clinically studied two cases of KID syndrome and extracted genomic DNA from peripheral blood. Results: The patients showed different heterozygous mutations of the connexin 26 gene and had quite different clinical courses. Conclusions: Both patients showed heterozygous mutations of the connexin 26 gene; a different Cx26 dominant mutation can cause a very different clinical course.

KID syndrome is rare. We report a 17-year-old girl who presented with universally ichthyotic red hue on the face, trunk, and extremities along with deafness and keratitis since childhood. She was diagnosed with KID syndrome. Treatment with acitretin cleared the hyperkeratotic ichthyotic lesions with little effect on the cornea or hearing. Acitretin seems to be a promising new treatment in KID syndrome.

Connexin26 (Cx26) mutations underlie human pathologies ranging from hearing loss to keratitis ichthyosis deafness (KID) syndrome. Cx26 hemichannels are directly gated by CO 2 and contribute to the chemosensory regulation of breathing. The KID syndrome mutation A88V is insensitive to CO 2, and has a dominant negative action on the CO 2 sensitivity of Cx26WT hemichannels, and reduces respiratory drive in humans. We have now examined the effect of further human mutations of Cx26 on its sensitivity to CO 2 . Mutated Cx26 subunits, carrying one of A88S, N14K, N14Y, M34T, or V84L, were transiently expressed in HeLa cells. The CO 2‐dependence of hemichannel activity, and their ability to exert dominant negative actions on cells stably expressing Cx26WT, was quantified by a dye‐loading assay. The KID syndrome mutation, N14K, abolished the sensitivity of Cx26 to CO 2. Both N14Y and N14K exerted a powerful dominant negative action on the CO 2 sensitivity of Cx26WT. None of the other mutations (all recessive) had a dominant negative action. A88S shifted the affinity of Cx26 to slightly higher levels without reducing its ability to fully open to CO 2. M34T did not change the affinity of Cx26 for CO 2 but reduced its ability to open in response to CO 2. V84L had no effect on the CO 2‐sensitivity of Cx26. Some pathological mutations of Cx26 can therefore alter the CO 2 sensitivity of Cx26 hemichannels. The loss of CO 2 sensitivity could contribute to pathology and consequent reduced respiratory drive could be an unrecognized comorbidity of these pathologies.

A 2-year-old male with KID syndrome was presented. Family history was negative for similar skin disease. The patient showed generalized ichthyosiform erythroderma, vascularizing keratitis, and neurosensory deafness. Additional clinical features included nail dystrophy, hypotrichosis, anhidrosis, and recurrent cutaneous bacterial and fungal infections. Histologic examination disclosed a basket-weave pattern of hyperkeratosis and irregular papillomatous configuration of the epidermis. Electron microscopic examination showed an excessive amount of glycogen in the cytoplasm of erector pili muscle cells. This is the first case reported in Japan.