Is palmoplantar keratoderma of Greither's type a separate nosologic entity?

Area of Science:

• Genetics
• Dermatology
• Medical Research

Background:

• Palmoplantar keratoderma (PPK) is a group of inherited skin disorders affecting the palms and soles.
• Understanding the genetic basis and clinical variability of PPK is crucial for diagnosis and management.
• Clan O provided a unique cohort for investigating familial PPK patterns.

Purpose of the Study:

• To investigate the prevalence and inheritance of palmoplantar keratoderma (PPK) within Clan O.
• To analyze the expressivity and associated features, such as knee hyperkeratosis, in affected individuals.
• To explore potential genetic heterogeneity or reduced penetrance in PPK.

Main Methods:

• Pedigree analysis of 48 investigated members of Clan O.
• Clinical examination of affected individuals, noting hyperkeratosis on palms, soles, and knees.
• Assessment of disease inheritance patterns across multiple generations.

Main Results:

• 17 out of 48 clan members were diagnosed with PPK.
• Five PPK patients exhibited significant knee hyperkeratosis.
• Inheritance of knee hyperkeratosis varied (dominant in one family, not in others); disease expressivity decreased in later generations.
• Associated conditions included incontinentia pigmenti (2 cases) and pollex duplex (1 case).

Conclusions:

• Palmoplantar keratoderma in Clan O displays variable expressivity and complex inheritance patterns.
• The observed decrease in expressivity across generations suggests potential genetic factors influencing disease presentation.
• Further research is warranted to clarify the genetic underpinnings and heterogeneity of this PPK subtype.