A new heterozygous frameshift variant in keratin 10 resulting in ichthyosis hystrix in a father and daughter.

Within epithelial tissues and hair and skin appendages, keratin intermediate filaments provide a robust structural scaffold to maintain cellular integrity. Encoded by 54 rare genes in 2 subgroupings, type 1 and type 2, >60 different disorders have been linked to inherited pathogenic variants in the keratins.1 One group of these keratins, which is predominantly expressed within the spinous layer of the epidermis, has been implicated in clinically heterogeneous forms of ichthyosis.2 Expression of the keratin 1 (encoded by KRT1)–keratin 10 (KRT10) pair reflects an early stage of terminal differentiation in the interfollicular epidermis.