BACKGROUND: Autosomal recessive congenital ichthyoses (ARCIs) are a clinically heterogeneous group of keratinization disorders characterized by generalized skin scaling due to mutations in at least 12 genes. The aim of our study was to assess disease severity, phenotypic, and ultrastructural features and to evaluate their association with genetic findings in ARCI patients.
METHODS: Clinical signs and symptoms, and disease severity were scored in a single-center series of patients with a genetic diagnosis of ARCI. Skin ultrastructural findings were reviewed.
RESULTS: Seventy-four consecutive patients (mean age 11.0 years, range 0.1-48.8) affected with lamellar ichthyosis (50/74, 67.5%), congenital ichthyosiform erythroderma (18/74, 24.3%), harlequin ichthyosis (two/74, 2.7%), and other minor ARCI subtypes (four/74, 5.4%) were enrolled. Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in 18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%), ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1, and SDR9C7 in 1 patient each (1.4%). Twenty-five previously undescribed mutations in the different ARCI causative genes, as well as two microduplications in TGM1, and two microdeletions in CYP4F22 and NIPAL4 were identified. The mean ichthyosis severity score in TGM1- and ABCA12-mutated patients was significantly higher than in all other mutated genes, while the lowest score was observed in CYP4F22-mutated patients. Alopecia, ectropion, and eclabium were significantly associated with TGM1 and ABCA12 mutations, and large, thick, and brownish scales with TGM1 mutations. Among specific phenotypic features, psoriasis-like lesions as well as a trunk reticulate scale pattern and striated keratoderma were present in NIPAL4-mutated patients. Ultrastructural data available for 56 patients showed a 100% specificity of cholesterol clefts for TGM1-mutated cases and revealed abnormal lamellar bodies in SDR9C7 and CERS3 patients.
CONCLUSIONS: Our study expands the phenotypic and genetic characterization of ARCI by the description of statistically significant associations between disease severity, specific clinical signs, and different mutated genes. Finally, we highlighted the presence of psoriasis-like lesions in NIPAL4-ARCI patients as a novel phenotypic feature with diagnostic and possible therapeutic implications.

Autosomal recessive congenital ichthyoses (ARCI) are a genetically heterogeneous group of rare and chronic disorders characterized by generalized skin scaling and hyperkeratosis, erythroderma, and palmoplantar keratoderma. Additional features include ectropion, eclabium, ear deformities, foul-smell, joints contractures and walking problems, recurrent infections, as well as pruritus and pain. No curative therapy is available and disease care mainly relies on daily application of topical emollients and keratolytics to the whole-body surface. Altogether, disease signs and symptoms and treatment modalities have a major impact on quality of life of patients and their caregivers. However, very few studies have evaluated the family disease burden in ARCI.
We have performed an Italian multicenter cross-sectional study to assess the secondary disease impact on family members of pediatric and adult patients with ARCI, using a validated dermatology-specific questionnaire, the family dermatology life quality index (FDLQI). Disease severity was assessed by the dermatologist in each center.
Seventy-eight out of 82 patients who were accompanied by at least one family member filled the FDLQI. Forty-eight (61.5%) patients were aged less than 18 years. The mean FDLQI score was 10.3 (median 10), and the most affected dimensions were (1) time needed for care, (2) extra-housework, and (3) household expenditure. Higher total FDLQI score significantly correlated with more severe disease score (P = 0.003). Features associated with greater family burden included recurrent infections (P = 0.004), foul-smell (P = 0.009), palmoplantar keratoderma (P = 0.041), but also presence of scales on the face (P = 0.039) and ear deformities (P = 0.016).
Our findings highlight the major socio-economic and psychological burden imposed by ARCI on the QoL of family caregivers. In addition, they show that global evaluation of disease impact also on family members is an essential part of patient-reported outcomes. Finally, our data underline the need to develop specific measures for family support.

Autosomal recessive congenital ichthyoses (ARCI) are rare genodermatosis disorders characterized by phenotypic and genetic heterogeneity. At least fourteen genes so far have been related to ARCI; however, despite genetic heterogeneity, phenotypes associated with mutation of different ARCI genes may overlap, thereby making difficult their clinical and molecular classification. In addition, molecular tests for diagnosis of such an extremely rare heterogeneous inherited disease are not easily available in clinical settings. In the attempt of identifying the genetic cause of the disease in four Italian patients with ARCI, we performed next-generation sequencing (NGS) analysis targeting 4811 genes that have been previously linked to human genetic diseases; we focused our analysis on the 13 known ARCI genes comprised in the panel. Nine different variants including three novel small nucleotide changes and two novel large deletions have been identified and validated in the ABCA12, ALOX12B, CYP4F22, and SULT2B1 genes. Notably, two patients had variants in more than one gene. The identification and validation of new pathogenic ABCA12, ALOX12B, CYP4F22, and SULT2B1 variants through multi-gene NGS in four cases of ARCI further highlight the importance of these genes in proper skin function and development.