Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of rare disorders of keratinization characterized by generalized abnormal scaling of the skin. Ten genes are currently known to be associated with ARCI: TGM1, ALOXE3, ALOX12B, NIPAL4 (ICHTHYIN), ABCA12, CYP4F22, PNPLA1, CERS3, SDR9C7, and SULT2B1. Over a period of 22 years, we have studied a large patient cohort from 770 families with a clinical diagnosis of ARCI. Since the first report that mutations in the gene CYP4F22 are causative for ARCI in 2006, we have identified 54 families with pathogenic mutations in CYP4F22 including 23 previously unreported mutations. In this report, we provide an up-to-date overview of all published and novel CYP4F22 mutations and point out possible mutation hot spots. We discuss the molecular and clinical findings, the genotype-phenotype correlations and consequences on genetic testing.
Background
Autosomal‐recessive congenital ichthyosis (ARCI) is a heterogeneous group of ichthyoses presenting at birth. Self‐improving congenital ichthyosis (SICI) is a subtype of ARCI and is diagnosed when skin condition improves remarkably (within years) after birth. So far, there are sparse data on SICI and quality of life (QoL) in this ARCI subtype. This study aims to further delineate the clinical spectrum of SICI as a rather unique subtype of ARCI.
Objectives
This prospective study included 78 patients (median age: 15 years) with ARCI who were subdivided in SICI (n = 18) and non‐SICI patients (nSICI, n = 60) by their ARCI phenotype.
Methods
Quality of life (QoL) was assessed using the (Children’s) Dermatology Life Quality Index. Statistical analysis was performed with chi‐squared and t‐Tests.
Results
The genetically confirmed SICI patients presented causative mutations in the following genes: ALOXE3 (8/16; 50.0%), ALOX12B (6/16; 37.5%), PNPLA1 (1/16; 6.3%) and CYP4F22 (1/16; 6.3%). Hypo‐/anhidrosis and insufficient vitamin D levels (<30 ng/mL) were often seen in SICI patients. Brachydactyly (a shortening of the 4th and 5th fingers) was statistically more frequent in SICI (P = 0.023) than in nSICI patients. A kink of the ear’s helix was seen in half of the SICI patients and tends to occur more frequently in patients with ALOX12B mutations (P = 0.005). QoL was less impaired in patients under the age of 16, regardless of ARCI type.
Conclusions
SICI is an underestimated, milder clinical variant of ARCI including distinct features such as brachydactyly and kinking of the ears. Clinical experts should be aware of these features when seeing neonates with a collodion membrane. SICI patients should be regularly checked for clinical parameters such as hypo‐/anhidrosis or vitamin D levels and monitored for changes in quality of life.
A 13-year-old girl presented with a 12-month history of intermittent edema and erythema of the extremities, which had been occurring at eight-week intervals. Clinical examination revealed subcutaneous edema with polycyclic violaceous hemorrhagic plaques (reminiscent of targetoid lesions) on her forearms, hands, and feet (Figures 1, 2 ). In addition, there was right palpebral edema and swelling of the cheek, which gave way to non-blanchable erythema within one day ( Figure 3 ). Each fl are had been preceded by an upper respiratory infection 1-2 days earlier. A throat swab had shown normal fl ora. During one episode, a urinary tract infection
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.