Heterozygous frameshift mutation in keratin 5 in a family with Galli-Galli disease

Galli-Galli Disease: A Comprehensive Literature Review

Galli-Galli disease (GGD) is a rare genodermatosis that exhibits autosomal dominant inheritance with variable penetrance. GGD typically manifests with erythematous macules, papules, and reticulate hyperpigmentation in flexural areas. A distinct atypical variant exists, which features brown macules predominantly on the trunk, lower limbs, and extremities, with a notable absence of the hallmark reticulated hyperpigmentation in flexural areas. This review includes a detailed literature search and examines cases since GGD's first description in 1982. It aims to synthesize the current knowledge on GGD, covering its etiology, clinical presentation, histopathology, diagnosis, and treatment. A significant aspect of this review is the exploration of the genetic, histopathological, and clinical parallels between GGD and Dowling-Degos disease (DDD), which is another rare autosomal dominant genodermatosis, particularly focusing on their shared mutations in the KRT5 and POGLUT1 genes. This supports the hypothesis that GGD and DDD may be different phenotypic expressions of the same pathological condition, although they have traditionally been recognized as separate entities, with suprabasal acantholysis being a distinctive feature of GGD. Lastly, this review discusses the existing treatment approaches, underscoring the absence of established guidelines and the limited effectiveness of various treatments.

Exacerbation of Galli-Galli Disease Following Dialysis Treatment: A Case Report and Review of Aggravating Factors

Galli-Galli disease (GGD) is a rare genodermatosis that is an acantholytic variant of Dowling-Degos disease that presents as lentigo-like macules/papules with progressive reticulated hyperpigmentation. Heat, sweat, ultraviolet light exposure, and topical retinoids have been reported to exacerbate the lesions associated with GGD. Here, we present a 77-year-old woman with end-stage renal disease and GGD who reported a worsening of lesions during the summer months and following hemodialysis treatment. Despite the severity of her lesions following dialysis, she refused treatment with isotretinoin out of concern for its side effect profile. In this case report, we discuss some available treatment options for GGD and review the exacerbating factors for GGD currently reported in the literature.

Hidradenitis Suppurativa Associated with Galli-Galli Disease: Extending the Link with Dowling-Degos Disease

Galli-Galli disease (GGD) is a rare genodermatosis that is distinguished from Dowling-Degos disease (DDD) by the histologic finding of acantholysis. We present a case of a female patient with pruritic intertriginous plaques and history of hidradenitis suppurativa (HS). While reports exist associating DDD with HS, to our knowledge, GGD in association with HS has not been reported in recent literature. HS in association with DDD has been found to have causal mutations, involving the gamma-secretase complex and POFUT1 genes. DDD also has shared causal mutations with GGD in the POGLUT1 and KRT5 genes. These three skin diseases have been linked to different gene mutations, which are all associated with the Notch signaling pathway.

Epidermal keratin 5 expression and distribution is under dermal influence

Human skin melanin pigmentation is regulated by systemic and local factors. According to the type of melanin produced by melanocytes, the transfer and degradation of melanosomes differ, thus accounting for most variations between ethnicities. We made the surprising observation that in a drastically changed environment, white and black phenotypes are reversible since Caucasian skin grafted onto nude mice can become black with all black phenotypic characteristics. Black xenografts differed essentially from other grafts by the levels of epidermal FGF-2 and keratin 5. In vitro analysis confirmed that FGF-2 directly regulates keratin 5. Interestingly, this phenomenon may be involved in human pathology. Keratin 5 mutations in Dowling-Degos Disease (DDD) have already been associated with the pheomelanosome-eumelanosome transition. In a DDD patient, keratin 5 was expressed in the basal and spinous layers, as observed in black xenografts. Furthermore, in a common age-related hyperpigmentation disorder like senile lentigo (SL), keratin 5 distribution is also altered. In conclusion, modulation of keratin 5 expression and distribution either due to mutations or factors may account for the development of pigmentary disorders.

Atypical Disseminated Variant of Galli-Galli Disease: A Review of the Literature

Galli-Galli disease (GGD) is a rare genodermatoses within the group of reticulated pigmentary disorders of the skin. Traditionally, its clinical presentation is identical to that of Dowling-Degos disease (DDD), with the additional feature of acantholysis on histopathological examination. We have reviewed the published cases of GGD to provide further support for the hypothesis that in fact, 2 phenotypes of GGD exist: the characteristic flexural GGD associated with KRT5 mutations and a disseminated variant with no mutation identified to date. A review of the literature revealed 53 reported cases of GGD. Fifteen atypical phenotype cases are described, and no KRT5 mutation has yet been identified. There is growing evidence that acantholysis is an underreported feature of DDD and that GGD and DDD are variations of the same disease, or in fact the same entity. This theory is supported by the identification of the c.418dupA missense mutation in both GGD and DDD. This review highlights that there is growing evidence that there are likely 2 clinical phenotypes of GGD with an associated genotypic correlation.

Updated review of genetic reticulate pigmentary disorders

Reticulate pigmentary disorders are a group of disorders characterized by hyper- and/or hypopigmented macules with varying sizes and amounts of pigment. Some of the disorders are heritable, such as Dowling-Degos disease, dyschromatosis universalis hereditaria, dyschromatosis symmetrica hereditaria, reticulate acropigmentation of Kitamura and X-linked reticulate pigmentary disorder. Although each condition possesses unique phenotypic characteristics and the prognosis for each is somewhat different, there is a large degree of overlap between the disorders and therefore they are difficult to differentiate in the clinical setting. This updated review provides a clinical and molecular delineation of these genetic reticulate pigmentary disorders and aims to establish a concise diagnostic strategy to allow clinical dermatologists to make an accurate diagnosis, as well as to provide useful information for clinical and genetic counselling.