Date: 01/28/2022

Journal: BMC Medical Imaging

Publication Type and Date: Case report and review of the literature, March 2021

Reference: Zhou Y, Liang L, Wang L, Zhang. Prenatal diagnosis of a rare variant of harlequin ichthyosis with literature review. BMC Med Imaging, 2021.

Review:

Harlequin ichthyosis (HI) is a rare ichthyosis that presents as large, plate-like scales covering the whole body, along with turned out lips (eclabium), turned out eyelids (ectropion) and flattened ears. There is rarely effective treatment for HI and mortality of affected patients is high. The authors report two cases of HI diagnosed with ultrasound during the third trimester. In case one, a 31-week ultrasound revealed thickening of the skin, ectropion, short nose bone, flat nose, open mouth and persistent flexion of the fingers and toes. In case two, a 30-week ultrasound, performed because of decreased fetal movements, showed similar findings.

The authors of this article reviewed the published literature over the past 20 years and found 10 cases of HI diagnosed through ultrasound. Three were identified during the second trimester and seven during the third trimester. Both 2D and 3D ultrasound used together best identify the features of HI. The characteristic features of HI on ultrasound will be apparent later in pregnancy and many pregnant women do not have an ultrasound during this latter part of gestation, when these features are evident.

Summary:

Fetal characteristics of HI appreciated on ultrasound include ectropion, abnormal double auricles, flattened nasal ridge, persistent open mouth, limb contractures and decreased movement. Additionally, the authors comment that particles floating in the amniotic fluid can be seen. Both 2D and 3D ultrasound performed together later in pregnancy are most likely to identify these features.

Journal: Journal of the American Academy of Dermatology

Publication Type and Date: Research letter, April 2021

Reference: Cuperus E, Bolling M, Graaf M, et al. Collodion babies: A 15-year retrospective multicenter study in The Netherlands- Evaluation of severity scores to predict the underlying disease. J Am Acad Dermatol. 2021.

Review:

Collodion baby can be the initial presentation in many different types of ichthyoses. A previous study by Rubio-Gomez et al proposed a clinical scoring system based on 15 characteristics of collodion. This previous study suggested extensive collodion was more associated with non-syndromic ichthyosis. The four major forms of non-syndromic ichthyosis include ichthyosis vulgaris, recessive X-linked ichthyosis, kertinopathic ichthyosis and autosomal recessive congenital ichthyosis.

The authors used the same collodion severity scoring system to evaluate 23 babies at three academic sites in the Netherlands. Genetic studies were completed on all babies and they were grouped into non-syndromic ichthyosis, syndromic ichthyosis, and self-healing collodion baby/unspecified congenital ichthyosis. The authors found no significant difference in the scores of the syndromic and non-syndromic ichthyosis groups. Although, the authors did find a trend toward lower severity scores in the syndromic ichthyosis group.

Summary:

A scoring system has been proposed as a way to measure severity of collodion and predict the underlying ichthyosis type. This scoring system has not been proven to reliably predict type of ichthyosis, although, lower scores have been seen in syndromic ichthyosis and higher scores in non-syndromic ichthyosis. It is possible that the small number of study patients contributed to the inability to assess the validity of the scoring system.

Journal: Journal of the American Medical Association Dermatology

Publication Type and Date:  Original investigation, December 2021

Reference: Sun Q, Burgren N, Cheraghlou S, et al. The Genomic and Phenotypic Landscape of Ichthyosis: An Analysis of 1000 Kindreds. JAMA Dermatol, 2021.

Review:

Over a 10 year period, the authors recruited  1000 patients from all over the world with ichthyosis to be a part of the study. Patients completed a questionnaire, genetic testing on blood or saliva, and standardized clinical photographs. Pathogenic variants of genetic material were identified in 869 participants. The authors identified 266 unique disease associated variants in 32 genes.

35% of patients with a genetic diagnosis completed the questionnaire. Itching, decreased sweating, skin pain, eye problems, skin odor and infections were the most commonly reported features.

• Collodion membrane at birth, skin odor, hearing problems, eye problems and alopecia were associated with patients who had TGM1 variant.
• Collodion membrane at birth was associated with patients who had ALOX12B variant.
• Skin pain, skin odor and skin infections were associated with patients who had KRT10 variant.
• Collodion membrane at birth and skin odor were associated with patients who had FLG variant.
• Collodion membrane at birth, skin pain, skin odor, skin infections, and hypohidrosis were associated with patients with STS variant.

Summary:

This study helps us expand the genetic causes of ichthyosis, along with the clinical features of different types of ichthyoses. The authors report specific clinical features of ichthyosis which are significantly associated with particular genetic causes. This can help doctors with diagnosis, and guide treatment plans for patients moving forward.