Self-improving congenital ichthyosisQ80.2

Autosomal recessiveself-improving congenital ichthyosis(SICI), also called self-healing collodion baby (SHCB), is a minus variant of non-syndromic autosomal recessive congenitalichthyosis(ARCI). Harlequin ichthyosis (OMIM:242500), the different variants of autosomal recessive lamellarichthyosis/congenital ichthyosiform erythroderma (see below congenital autosomal recessive ichthyoses). "Self-improving congenital ichthyosis" is characterized by the presence of a collodion membrane at birth. This heals within the first few weeks of life. Adults develop varying degrees of ichthyosis, usually mild.

Prevalence: <1 / 1 000 000

Mutations in 3 genes, ALOX12B, ALOXE3, and TGM1 are associated with self-healing congenital ichthyosis, with mutations in ALOX12B being the most common. The ALOX12B and ALOXE3 genes encode the epidermal lipoxygenases arachidonate 12-lipoxygenase, i.e., 12R-type (12R-LOX), and epidermal-type lipoxygenase-3 (eLOX3), respectively.

Deficiency of 12R-LOX and eLOX3 disrupts epidermal barrier function and leads to abnormal epidermal differentiation. To date, 88 pathogenic mutations in ALOX12B and 27 pathogenic mutations in ALOXE3 have been described in the literature.

Neonatal

Infants born with congenital autosomal recessive ichthyosis (ARCI) are often enveloped by a collodion membrane that, when detached, reveals a lamellar or erythrodermic form of ichthyosis.

However, some newborns show spontaneous detachment of the collodion membrane 2-4 weeks after birth and subsequently present near-normal skin. This phenotype is referred to as"self-healing collodion baby" (SHCB) or self-healing congenital ichthyosis.

In a Swedish/Danish collective, at a later examination, patients aged 2 to 37 years showed mild xerosis of the skin, mild or focal scaling, hyperlinearity of the palms with keratoderma, and erythrosis facialis combined with anhidrosis.

1. Anker Pet al. (2021) Report of a Novel ALOX12B Mutation in Self-Improving Collodion Ichthyosis with an Overview of the Genetic Background of the Collodion Baby Phenotype. Life (Basel) 11:624.
2. Hotz A et al. (2021) Meta-Analysis of Mutations in ALOX12B or ALOXE3 Identified in a Large Cohort of 224 Patients. Genes (Basel) 12: 80.
3. Vahlquist A et al. (2010) Genotypic and clinical spectrum of self-improving collodion ichthyosis: ALOX12B, ALOXE3, and TGM1 mutations in Scandinavian patients. J Invest Dermatol 130:438-443.