What is the Difference Between Lamellar Ichthyosis and Harlequin Ichthyosis

The key difference between lamellar ichthyosis and harlequin ichthyosis is that lamellar ichthyosis is a relatively common type of autosomal recessive congenital ichthyosis, usually seen in babies who start with a collodion membrane that turns into large, white, and later brown, plate-like scales, while harlequin ichthyosis is a less common form of autosomal recessive congenital ichthyosis, where babies develop thick, tough, armor-like skin plates with deep fissures.

Autosomal recessive congenital ichthyoses (ARCI) are lifelong genetic skin disorders with generalized scaling and variable erythema. Autosomal recessive congenital ichthyoses are typically present at birth or early infancy. Lamellar ichthyosis and harlequin ichthyosis are two different forms of autosomal recessive congenital ichthyoses.

CONTENTS

1. Overview and Key Difference
2. What is Lamellar Ichthyosis 
3. What is Harlequin Ichthyosis
4. Similarities – Lamellar Ichthyosis and Harlequin Ichthyosis
5. Lamellar Ichthyosis vs. Harlequin Ichthyosis in Tabular Form
6. Summary – Lamellar Ichthyosis vs. Harlequin Ichthyosis

What is Lamellar Ichthyosis?

Lamellar ichthyosis (LI) is a genetic skin disorder that is present at birth. It is one of the three genetic skin disorders categorized under autosomal recessive congenital ichthyoses (ARCI). The other two skin disorders coming under ARCI are harlequin ichthyosis and congenital ichthyosiform. Mutations in the TGM1 gene normally cause lamellar ichthyosis. Moreover, the typical symptoms of this condition may include babies that are born with a clear, shiny, waxy layer of skin called a collodion membrane, difficulty in feeding, dehydration, loss of balance of minerals in the body, breathing problems, unstable body temperature, skin or body-wide infections, giant scales that cover most of the body, decreased ability to sweat, hair loss, abnormal fingers and toenails, and thickened skin of the palms and soles.

Lamellar ichthyosis is diagnosed through electron microscopic examination of fetal skin biopsies, examination of amniotic fluid cells obtained via fetoscopy, and DNA-based molecular genetic testing. Furthermore, lamellar ichthyosis is generally treated through moisturizers applied to the skin, medicines (retinoids taken by mouth), providing a high-humidity environment, and bathing to loosen scales.

What is Harlequin Ichthyosis?

Harlequin ichthyosis is a severe genetic disorder categorized under autosomal recessive congenital ichthyoses. Infants with this condition are born prematurely with very hard, thick skin, which covers most parts of their bodies. Variants or mutations in the ABCA12 gene cause harlequin ichthyosis. The typical symptoms of these conditions may include eyelids turning inside out, eyes not closing normally, lips pulled tight, making nursing difficult, fused ears to the head, small, swollen hands and feet, limited mobility, breathing problems, different infections in deep skin cracks, dehydration, lower body temperature, hypernatremia, sparse hair, unusual facial features, reduced hearing, problems with finger movements, thick fingernails, overheating due to scales.

Harlequin ichthyosis is diagnosed through examination of skin appearance and genetic testing. Furthermore, treatment options for harlequin ichthyosis may include letting the babies spend time in a heated incubator with high humidity, applying retinoids to help shed hard scales in the skin, applying topical antibiotics to prevent recurrent infection, covering the skin in bandages, placing a tube in the airway to ease the difficulty in breathing, using lubricating eye drops on the eyes, and keeping the skin clean and moist using skin moisturizers.

What are the Similarities Between Lamellar Ichthyosis and Harlequin Ichthyosis?

• Lamellar ichthyosis and harlequin ichthyosis are two different forms of autosomal recessive congenital ichthyoses.
• Both disorders are inherited in an autosomal recessive pattern.
• They may show similar symptoms, such as scaling, variable erythema, feeding difficulties, breathing difficulties, dehydration, and body temperature problems.
• Both disorders are diagnosed through examination of physical appearance and genetic testing.
• They are mainly treated by applying skin moisturizers and retinoids.

What is the Difference Between Lamellar Ichthyosis and Harlequin Ichthyosis?

Lamellar ichthyosis is a relatively common type of autosomal recessive congenital ichthyosis, usually seen in babies who start with a collodion membrane that turns into large, white, and later brown, plate-like scales, while harlequin ichthyosis is a less common form of autosomal recessive congenital ichthyosis, where babies develop thick, tough, armor-like skin plates with deep fissures. Thus, this is the key difference between lamellar ichthyosis and harlequin ichthyosis. Moreover, harlequin ichthyosis is a more severe form of autosomal recessive congenital ichthyoses.

The infographic below presents the differences between lamellar ichthyosis and harlequin ichthyosis in tabular form for side-by-side comparison.

Summary – Lamellar Ichthyosis vs Harlequin Ichthyosis

ARCI refers to a group of rare genetic skin disorders that are lifelong with generalized scaling and variable erythema. Lamellar ichthyosis and harlequin ichthyosis are two different forms of autosomal recessive congenital ichthyoses. Lamellar ichthyosis is characterized by babies who start with a collodion membrane that turns into large, white, and later brown, plate-like scales, while harlequin ichthyosis is characterized by babies who develop thick, tough, armor-like skin plates with deep fissures. Moreover, lamellar ichthyosis is mainly due to mutations in the TGM1 gene, whereas harlequin ichthyosis is mainly due to mutations in the ABCA12 gene. So, this summarizes the difference between lamellar ichthyosis and harlequin ichthyosis.

Reference:

1. “Lamellar Ichthyosis.”ScienceDirect Topics.
2. “Harlequin Ichthyosis – about the Disease.” Genetic and Rare Diseases Information Center.

Image Courtesy:

1. “Ichthyosis 2” By George Henry Fox – Fox, George Henry (1886) Photographic illustrations of skin diseases (2nd ed.), E.B. Treat Retrieved on 25 September 2010. (Public Domain) via Commons Wikimedia
2. “Harlequin ichthyosis (2)” By Dubey, Alok Kumar; Tuibeqa, Ilisapeci Vereti; Pio, Nina BaivouStretching applied by User: SUM1. – Dubey, Alok Kumar; Tuibeqa, Ilisapeci Vereti; Pio, Nina Baivou (4 July 2014).”Harlequin ichthyosis: A rare dermatological disorder”. International Journal of Case Reports and Images (IJCRI). 5 (8): 590–594. doi:10.5348/ijcri-2014105-CR-10416. ISSN 0976-3198. (CC BY 4.0) via Commons Wikimedia