D2I2.
genetic

Pachyonychia congenita

Pachyonychia congenita is a rare group of skin disorders that are caused by a in one of five different keratin genes. Pachyonychia congenita is often associated with thickened toenails, plantar keratoderma, and plantar pain.

Underlined words are explained — tap any of them.

Plain-language summary adapted from Wikipedia. Not medical advice.