Dowling-Degos disease (reticulate pigmented anomaly of the flexures) is an autosomal dominant condition

The Genomic Architecture of Hidradenitis Suppurativa-A Systematic Review

Hidradenitis suppurativa is a chronic, suppurative condition of the pilosebaceous unit manifesting as painful nodules, abscesses, and sinus tracts mostly in, but not limited to, intertriginous skin. Great strides have been made at elucidating the pathophysiology of hidradenitis suppurativa, which appears to be the product of hyperkeratinization and inflammation brought about by environmental factors and a genetic predisposition. The identification of familial hidradenitis suppurativa has sparked research aimed at identifying underlying pathogenic variants in patients who harbor them. The objective of this review is to provide a broad overview of the role of genetics in various aspects of hidradenitis suppurativa, specifically the pathophysiology, diagnosis, and clinical application.

Keratins and epidermolysis bullosa simplex

Keratin intermediate filaments play an important role in maintaining the integrity of the skin structure. Understanding the importance of this subject is possible with the investigation of keratin defects in epidermolysis bullosa simplex (EBS). Nowadays, in addition to clinical criteria, new molecular diagnostic methods, such as next generation sequencing, can help to distinguish the subgroups of EBS more precisely. Because the most important and most commonly occurring molecular defects in these patients are the defects of keratins 5 and14 (KRT5 and KRT14), comprehending the nature structure of these proteins and their involved processes can be very effective in understanding the pathophysiology of this disease and providing new and effective therapeutic platforms to treat it. Here, we summarized the various aspects of the presence of KRT5 and KRT14 in the epidermis, their relation to the incidence and severity of EBS phenotypes, and the processes with which these proteins can affect them.

A Study of Immunohistochemical and Electron Microscopic Changes in Dowling-Degos Disease

Previous investigations have focused on the skin manifestations, histopathology, and pedigree of patients with Dowling-Degos disease (DDD). Little is known about its immunohistochemical staining, and electron microscopy. Our purpose was to study the immunohistochemistry and electron microscopy of lesions from patients with DDD. A biopsy specimen revealed elongated epidermal rete ridges with basilar hyperpigmentation in a filiform pattern. All pigmented cells in the basal layer were recognized by Anti-PEP-1, anti-PEP-2, HMB-45 and NKI/beteb antibodies. The melanocytes were localized in the basal layer and accounted for 10% of the total keratinocytes. There were supranuclear "caps" of brown granules within most basal kerotinocytes in the hyperpigmentation area. The melanocytes contained many mitochondria, Golgi apparati, and regular melanosomes in all stages of maturation in their cytoplasms; melanosome-laden dendrites were readily detected by transmission electron microscepe. Melanosomes, mainly of stages III and IV, were present within keratinocytes, distributed either as scattered patterns or forming "caps" over the nucleus.

Generalized dowling-degos disease: case reports

Dowling-Degos disease (DDD) is a rare autosomal dominant trait characterized by numerous, symmetrical, progressive and pigmented macules over the axillae, groins, face, neck, arms and trunk as well as scattered comedo-like lesions (dark dot, follicles) and pitted acneiform scars. Histopathology is diagnostic testing using a distinctive form of acanthosis, characterized by an irregular elongation of thin branching rete ridges, with a concentration of melanin at the tips. We report cases of generalized DDD in a single family with autosomal dominant penetrance. DDD can be presented in a generalized form with hypopigmented lesions instead of reticulate hyperpigmentation confined to the flexor areas. This form can be differentiated from DUH by histopathology.

Generalized Dowling-Degos disease

BACKGROUND

Dowling-Degos disease (DDD) is a rare inherited disease characterized by reticular hyperpigmentation on flexor surfaces.

OBJECTIVE

We sought to describe several cases of generalized DDD, a presentation that resemble dyschromatosis universalis hereditaria.

METHODS

The clinical manifestations, histopathologic, and genetic studies of a family with autosomal dominant inheritance were analyzed.

RESULTS

The father and his sister had reticular hyperpigmentation on flexor surfaces, whereas the daughter and son had generalized hyperpigmentation with numerous hypopigmented or erythematous macules and papules on the trunk and limbs. Skin biopsy specimens from both types of lesions all had typical features of DDD. Biopsy specimens from axillary skin had features of Galli-Galli disease, an acantholytic form. There were no mutations of the double-stranded RNA-specific adenosine deaminase or keratin 5 genes.

LIMITATION

Generalizations cannot be drawn from genetic study of only one family.

CONCLUSION

DDD can present with generalized hyperpigmentation and hypopigmented papules.

A Gene Locus Responsible for Reticulate Pigmented Anomaly of the Flexures Maps to Chromosome 17p13.3

Reticulate pigmented anomaly of the flexures (RPAF), also called Dowling-Degos disease, is a rare autosomal-dominant cutaneous disorder characterized by spotted and reticulate pigmentation of the flexures. The gene, or even the chromosomal location, for RPAF has not yet been identified. In this study, one Chinese family with RPAF was identified and subjected to a genomewide screen for linkage analysis. We identified a locus at chromosome 17p13.3 with a maximum two-point limit of detection score of 3.61 at markers D17S831and D17S1866 (at recombination fraction theta=0.00). Haplotype analyses indicated that the disease gene is located within the 6.8 cM region distal to D17S1798. It is the first locus identified for RPAF. This study provides a map location for isolation of a disease gene causing RPAF.

Loss-of-function mutations in the keratin 5 gene lead to Dowling-Degos disease

Dowling-Degos disease (DDD) is an autosomal dominant genodermatosis characterized by progressive and disfiguring reticulate hyperpigmentation of the flexures. We performed a genomewide linkage analysis of two German families and mapped DDD to chromosome 12q, with a total LOD score of 4.42 ( theta =0.0) for marker D12S368. This region includes the keratin gene cluster, which we screened for mutations. We identified loss-of-function mutations in the keratin 5 gene (KRT5) in all affected family members and in six unrelated patients with DDD. These represent the first identified mutations that lead to haploinsufficiency in a keratin gene. The identification of loss-of-function mutations, along with the results from additional functional studies, suggest a crucial role for keratins in the organization of cell adhesion, melanosome uptake, organelle transport, and nuclear anchorage.

Dowling-Degos disease with dyschromatosis universalis hereditaria-like pigmentation in a family

Dowling-Degos disease is a rare autosomal dominant inherited pigmentary disorder characterized by reticulate pigmentation of the flexures, prominent comedone like lesions and pitted scars. Dyschromatosis universalis hereditaria is characterized by the presence of hypopigmented as well as hyperpigmented macules. We report a family showing features of both these diseases.

Hidradenitis suppurativa, Dowling-Degos and multiple epidermal cysts: a new follicular occlusion triad

This case illustrates the rare association between hidradenitis suppurativa (HS) and Dowling-Degos disease (DDD). Furthermore the association of HS, DDD and multiple epidermal cysts has not to our knowledge been described before, but their coexistence in the same patient is likely to reflect the same follicular anomaly. It is possible that a single underlying defect of follicular proliferation may account for the coexistence of these conditions.

Generalized mottled pigmentation with postnatal skin blistering in three generations

We describe three generations of a family expressing progressive mottled hypopigmentation and hyperpigmentation on the non-exposed parts of the body from childhood to adult life. At birth, they all had epidermal blistering of the distal extremities. Although the palmoplantar warty keratoses could be related to the bulla formation, the pigmentary changes could not. Otherwise, there were no systemic disorders. Genetic diseases with spotty epidermal hypopigmentation and hyperpigmentation form a long list and the diagnosis is not always easy. Although different diagnostically, the condition resembled an entity described by Siemens in 1922 and epidermolysis bullosa with mottled pigmentation. Molecular biological investigation would be required to characterize the phenotype of this entity, which apparently was a mutation occurring in one family for three generations.

Reticulate acropigmentation of Dohi: a case report of autosomal recessive inheritance

Reticulate acropigmentation of Dohi is a rare dyschromic disorder that generally has an autosomal dominant pattern of inheritance. Most of the cases have primarily been described from Japan. Only a few similar cases have been described elsewhere. We describe 3 black siblings, one boy and two girls, who had progressive reticulate hyperpigmented and hypopigmented macules over the dorsa of hands and feet, which began in early childhood. There were no palmar pits or breaks of the epidermal rete ridge pattern nor was there a family history of any pigmentary skin diseases. Three skin biopsies were performed on one patient; a biopsy specimen from a hyperpigmented macule showed increased melanin in all epidermal levels tapering towards the surface, a second biopsy specimen from a hypopigmented macule showed much less melanin, but it had a similar distribution. A third specimen from a hyperpigmented macule for electron microscopy showed a moderate number of stage III and IV melanosomes in the cytoplasm of the melanocytes. To our knowledge, these patients are the first cases reported from the Middle East with an autosomal recessive pattern of inheritance, confirming previous reports.

Is Dowling-Degos disease the same disease as Kitamura's reticulate acropigmentation?

A patient is described with the clinical and histopathological features of both Dowling-Degos disease and Kitamura's acropigmentatio reticularis. The possible identity of the two genodermatoses is discussed on the basis of the similarity of their clinical and histopathological features and of the presence of the two diseases in the family of the propositus.