- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 2/2. (PMID:16505000)
- Abnormal blistering of the skin (HP:0008066): The presence of one or more bullae on the skin, defined as fluid-filled blisters more than 5 mm in diameter with thin walls. Evidence: PCS. Frequency: 4/11. (PMID:7509230;PMID:1380725)
- Generalized hyperkeratosis (HP:0005595). Evidence: PCS. Frequency: 11/13. (PMID:7509230;PMID:1380725;PMID:16505000)
- Autosomal recessive inheritance (HP:0000007): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:1380725)
- Erythroderma (HP:0001019): An inflammatory exfoliative dermatosis involving nearly all of the surface of the skin. Erythroderma develops suddenly. A patchy erythema may generalize and spread to affect most of the skin. Scaling may appear in 2-6 days and be accompanied by hot, red, dry skin, malaise, and fever. Evidence: PCS. Frequency: 2/2. (PMID:16505000)
- Cobblestone-like hyperkeratosis (HP:0031288): The presence of verrucous, cobblestone-like papules and nodules in a region of skin that is said to have an appearance like that of cobblestones. Evidence: PCS. Frequency: 1/2. (PMID:16505000)
- Palmoplantar hyperkeratosis (HP:0000972): Abnormal thickening of the skin localized to the palm of the hand and the sole of the foot. Evidence: PCS. Frequency: 2/10. (PMID:7509230;PMID:16505000)
- Congenital nonbullous ichthyosiform erythroderma (HP:0007479): The term collodion baby applies to newborns who appear to have an extra layer of skin (known as a collodion membrane) that has a collodion-like quality. It is a descriptive term, not a specific diagnosis or disorder (as such, it is a syndrome). Affected babies are born in a collodion membrane, a shiny waxy outer layer to the skin. This is shed 10-14 days after birth, revealing the main symptom of the disease, extensive scaling of the skin caused by hyperkeratosis. With increasing age, the scaling tends to be concentrated around joints in areas such as the groin, the armpits, the inside of the elbow and the neck. The scales often tile the skin and may resemble fish scales. Evidence: PCS. Frequency: 2/2. (PMID:16505000)
- Palmoplantar keratoderma (HP:0000982): Abnormal thickening of the skin of the palms of the hands and the soles of the feet. Evidence: PCS. Frequency: 2/3. (PMID:1380725)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:7509230)
- Hyperkeratosis (HP:0000962): Hyperkeratosis is a histopathological term defining a thickened stratum corneum and may be present in many different skin conditions, with many possible overlaps. Hyperkeratosis refers to the increased thickness of the stratum corneum, the outer layer of the skin. Hyperkeratosis is subclassified as orthokeratotic or parakeratotic. Orthokeratotic hyperkeratosis refers to the thickening of the keratin layer with preserved keratinocyte maturation, while parakeratotic hyperkeratosis shows retained nuclei as a sign of delayed maturation of keratinocytes. Evidence: PCS. Frequency: 1/8. (PMID:7509230)
These phenotypes are associated with the disease epidermolytic hyperkeratosis 2A, autosomal dominant (OMIM:620150).