Spitz_Genodermatoses, 3e

Introduction

I t is a pleasure to introduce the newest edition of “ Genodermatoses ,” a textbook that takes a complex group of disorders and highlights important disease features while provid ing numerous illustrations. The enduring popularity of “The Spitz Textbook” among trainees emphasizes the power of artistic drawings, as well as photographs, to illustrate important disease components. The availability of advanced technology, both whole ex ome sequencing and whole genome sequencing, to elucidate the underlying basis for genetic disorders has revolutionized our ability to diagnose subtypes of genodermatoses. In many cases, this information is important for prenatal diagnosis, offering prognostic clues and, in some cases, suggesting new therapeutic directions. However, our recogni tion of clinical patterns that indicate disease will never be replaced and remain paramount to classification by group of genodermatoses (eg, ichthyosis, epidermolysis bullosa, ecto dermal dysplasia), leading to management decisions and choice of the appropriate panel for testing early in life to define the underlying cause. It is reassuring and important that despite stunning advances in molecular genetics, physical examination continues to be the cornerstone of genetic diagnosis for all clinicians. Each chapter in this book describes a group of disorders that are associated with a specific biologic abnormality of the skin. For example, Chapter 2 focuses on disorders of pigmentation, each caused by disruption of melanin biogenesis or function. Chapter by chapter, these groups of disorders provide a view of essential components of skin biology and how dysfunction through genetic variants and alterations in resultant proteins leads to disease. Given the complexity and multicell composition of skin, these altered proteins may impact dermal connective tissue (as in Ehlers-Danlos syndrome), skin repair after UV damage (as in xeroderma pigmentosum), regulation of cell proliferation or survival (as in tumor syndromes), the lipid or protein epidermal barrier (as in the ichthyoses), adherence of epidermis to dermis (as in epidermolysis bullosa), and many other functions. Taken to gether, the various genetic disorders of skin tell a story of how skin cells work in a coordi nated manner to maintain skin integrity and function. As in prior editions of Spitz’s Genodermatoses, gene names are included in each dis order description. It is now common to seek the genetic basis of skin disorders, especially since available tests to discover underlying gene variants have become both simpler tech nically and less costly. Not only is the genetic basis for these diseases appearing in most reports, but increasingly disease names are being altered to include the variant gene itself, as for the upcoming reclassification of ichthyoses and palmoplantar keratodermas. As a result, gene names included in this text are written in italics to distinguish gene, allele, and RNA names from the names of protein products. Most genetic disorders described in this book are rare. The now multiple authors of Genodermatoses have included pearls from their own experience, as well as from the input of patients and support groups. As such, readers will find a wealth of information that is both accurate and valuable. In addition to the concise information imparted in the text, readers are encouraged to learn more about the various genodermatoses from their pa tients and through participating in the many advocacy groups that provide educational and social networking support to patients and families whose lives are impacted by ge netic skin disease.

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Amy S. Paller, MD November 2023

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