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

Novel Presentation of Reticulate Acropigmentation of Kitamura With Bilateral Clinodactyly

Reticulate acropigmentation of Kitamura (RAPK) is a rare genetic hyperpigmentation disorder that is a member of the dyschromatoses characterized by hyperpigmented macules or papules that may interrupt the dermatoglyphics with extra-dermatological manifestations. We present a case of a 29-year-old black male who presented with hyperpigmented atrophic macules both on the extremities and genitals, as well as bilateral clinodactyly of the 5th fingers and inferior gingival hyperplasia with teeth crowding, to draw attention to the novel extra dermatological manifestations of RAPK and the differential diagnosis of cutaneous hyperpigmented lesions.

Cutaneous signs in dermatological diseases; An overview

Cutaneous signs in dermatology are pathognomonic or diagnostic for certain conditions. A knowledge of these signs is a useful skill, which must not be forgotten in the recent trend towards relying on molecular biology and other investigative tools including histological findings to make a diagnosis. The aim of this review is to summarize all cutaneous signs in dermatology in a systematic way that would benefit dermatologists, trainee or experienced, in identifying diseases and sharpening their clinical skills. A keyword search for the terms “cutaneous signs,” “sign” AND “dermatology” was conducted through PUBMED, Google, and the major textbooks in dermatology (i.e., Rooks Textbook of Dermatology; Fitzpatrick's Dermatology in General Medicine and Dermatology). References were searched thoroughly for all cutaneous signs described. One hundred and nineteen signs were noted and summarized under the following categories: autoimmune, infective, inflammatory, neoplastic, genetic, trauma/miscellaneous. This review would serve as a good reference for those wanting to improve their clinical acumen in diagnosing dermatological disease.

Dyschromatosis symmetrica hereditaria with cutaneous lupus erythematosus and hyperthyroidism

Dyschromatosis symmetrica hereditaria (DSH) is a rare genodermatosis characterized by various sizes of both hyper- and hypopigmented macules arranged in reticulated patterns on the face and the dorsal aspects of the extremities. There are also cutaneous and extracutaneous abnormalities, but they are rare. As far as we know, DSH associated with immune-mediated conditions has not been reported. We report the first case of DSH, which is associated with cutaneous lupus erythematosus and hyperthyroidism.

Autosomal-recessive SASH1 variants associated with a new genodermatosis with pigmentation defects, palmoplantar keratoderma and skin carcinoma

SASH1 (SAM and SH3 domain-containing protein 1) is a tumor suppressor gene involved in the tumorigenesis of a spectrum of solid cancers. Heterozygous SASH1 variants are known to cause autosomal-dominant dyschromatosis. Homozygosity mapping and whole-exome sequencing were performed in a consanguineous Moroccan family with two affected siblings presenting an unclassified phenotype associating an abnormal pigmentation pattern (hypo- and hyperpigmented macules of the trunk and face and areas of reticular hypo- and hyperpigmentation of the extremities), alopecia, palmoplantar keratoderma, ungueal dystrophy and recurrent spinocellular carcinoma. We identified a homozygous variant in SASH1 (c.1849G>A; p.Glu617Lys) in both affected individuals. Wound-healing assay showed that the patient's fibroblasts were better able than control fibroblasts to migrate. Following the identification of SASH1 heterozygous variants in dyschromatosis, we used reverse phenotyping to show that autosomal-recessive variants of this gene could be responsible for an overlapping but more complex phenotype that affected skin appendages. SASH1 should be added to the list of genes responsible for autosomal-dominant and -recessive genodermatosis, with no phenotype in heterozygous patients in the recessive form, and to the list of genes responsible for a predisposition to skin cancer.

[Hands cutaneous exam]

There are four different areas to consider: palms, back of the hands, fingers, periungual folds (and nails). Palmoplantar keratodermas are a group of inherited or acquired disorders. Dysidrosis is a peculiar form of eczema on the palms and lateral aspects of the fingers. SAPHO syndrome (Synovitis - Acne - Pustulosis - Hyperostosis - Osteomyelitis) presents pustules on palms. Photo-ageing is frequently noticed on the back of the hands. Paraneoplastic acrokeratosis (Bazex syndrome) affects the nose, ears, and periungual folds of fingers and toes. Spontaneous blue finger syndrome can be a benign process that resolves rapidly.

A case of dowling-degos disease on the vulva

Dowling-Degos disease (DDD) is an autosomal dominant genodermatosis and this disease is a genetically determined disturbance of epidermal proliferation. It is characterized by acquired, slowly progressive pigmented lesions that primarily involve the great skin folds and flexural areas such as the axilla, neck, limb flexures, the inframammary area and the inguinal folds. The vulva is an unusual location for DDD. A 41-year-old woman presented with a 10-year history of multiple, small, reticulated and brownish macules distributed symmetrically on the bilateral external genital regions. We found no other similarly pigmented skin lesions on her body, including the flexural areas. There was no known family history of similar eruptions or pigmentary changes. The histologic examination showed irregular rete ridge elongation with a filiform or antler-like pattern and basilar hyperpigmentation on the tips. Fontana-Masson staining showed increased pigmentation of the rete ridges and the S100 protein staining did not reveal an increased number of melanocytes in the epidermis. From these findings, we diagnosed this lesion as DDD.

[Case for diagnosis. Dyschromatosis symetrica hereditaria]

Dyschromatosis symetrica hereditaria (reticulate acropigmentation of Dohi) is a rare autosomal dominant disease. It starts as hyperpigmented and hypopigmented macules in reticular pattern on the extremities. We present a case of a 13-year old boy that showed hyper and hypopigmented macules distributed on the dorsal aspects of the extremities, freckle-like pigmented macules on the face and periorbital atrophic linear lesions. Differentiation with others reticulate pigmentation manifestations is necessary.

Dyschromatosis universalis hereditaria: evidence for autosomal recessive inheritance and identification of a new locus on chromosome 12q21-q23

Dyschromatosis universalis hereditaria (DUH) and dyschromatosis symmetrica hereditaria (DSH) are pigmentary dermatoses most commonly seen in Japan. Both disorders usually show autosomal dominant inheritance, although in some cases autosomal recessive inheritance was reported. DSH was mapped to chromosome 1q21.3, and mutations in the gene ADAR (DSRAD) were identified in Japanese, Chinese and Taiwanese families with autosomal dominant DSH. A second locus for dyschromatosis was mapped on chromosome 6q24.2-q25.2 in two Chinese families initially reported to be affected with DSH, but later suggested to have autosomal dominant DUH. The aim of this study was to investigate whether one of these two loci is involved in the development of DUH in a consanguineous Bedouin family from Saudi Arabia with four affected and three unaffected sibs, clearly pointing to autosomal recessive inheritance. After excluding mutations in ADAR and linkage to the candidate regions on chromosomes 1 and 6, we performed an single nucleotide polymorphism-based genome-wide scan for linkage with other loci. Under the assumption of autosomal recessive inheritance, we have identified a new locus for dyschromatosis on chromosome 12q21-q23 in this Arab family with a maximum logarithm of the odds (LOD) score of 3.4, spanning a distance of 18.9 cM. Our study revealed the first locus for autosomal recessive DUH and supports recent evidence that DSH and DUH are genetically distinct disorders.

A novel missense mutation in DSRAD in a family with dyschromatosis symmetrica hereditaria

Dyschromatosis symmetrica hereditaria (DSH) is a rare autosomal dominant cutaneous disorder characterized by a mixture of hyperpigmented and hypopigmented macules of various sizes on the extremities. Pathogenic mutations in the DSRAD gene have been identified. In this report, we identified a Chinese family with a three-generation pedigree of DSH, in which a novel heterozygous nucleotide G-->A transition was found. It is at position 3,125 in exon 12 of the DSRAD gene which induces a R1042H change in the putative deaminase domain of DSRAD. Our study expands the database on the DSRAD gene mutations in DSH.

Identification of two novel DSRAD mutations in two Chinese families with dyschromatosis symmetrica hereditaria

Dyschromatosis symmetrica hereditaria (DSH) is a hereditary skin disease characterized by the presence of hyperpigmented and hypopigmented macules on face and dorsal aspects of the extremities that appear in infancy or early childhood. Genetic studies have identified mutations in the double-stranded RNA-specific adenosine deaminase (DSRAD) gene, encoding double-stranded RNA-specific adenosine deaminase, to be responsible for this disorder. Here, we report two novel mutations c.2116 G > A (E706K) and c.2848 C > T (Q950X) in the DSRAD gene identified in two Chinese pedigrees with DSH. This study should be useful for genetic counseling and prenatal diagnosis for affected families and in expanding the database on DSRAD gene mutations in DSH.

Familial gigantic melanocytosis

BACKGROUND

Familial gigantic melanocytosis (FGM) is a rare disorder first described in 1984 and termed "familial melanopathy with gigantic melanocytes". The cause of the disorder is still unknown. Melanocytes in both hyper- and hypopigmented skin seem to be unable to deliver melanin to the surrounding keratinocytes.

OBJECTIVE

In this study, we report four new cases of FGM. Electron microscopic examination was performed in a trial to shed more light on the underlying defect in this disorder.

PATIENTS AND METHODS

Patients were examined clinically and biopsies were taken from both hyperpigmented and hypopigmented areas, and divided into two parts; one part was processed for routine microscopic examination with hematoxylin and eosin and Masson Fontana stains. The other portion of the biopsy was fixed in glutraldhyde 3% and processed for electron microscopic (EM) examination.

RESULTS

By light microscopy, the patients' skin showed areas of hyperpigmented basal cells alternating with poorly pigmented areas. Hair follicles in the scalp biopsies showed the same pathology. By EM, pigmented areas showed gigantic melanocytes and heavily pigmented keratinocytes. Nonpigmented areas showed poorly pigmented keratinocytes and fewer, but also gigantic melanocytes.

CONCLUSIONS

The raindrop-like hypopigmentation in this disorder can be explained by a failure of melanocytes to deliver melanin to their surrounding keratinocytes. The cause of the presence of heavily pigmented keratinocytes in the hyperpigmented zones could not be determined. There is a strong possibility of a more widespread abnormality affecting not just the melanocytes.

Identification of a novel ADAR mutation in a Chinese family with dyschromatosis symmetrica hereditaria (DSH)

Dyschromatosis symmetrica hereditaria (DSH [MIM 127400]) is characterized by the presence of hyperpigmented and hypopigmented macules mostly on the dorsal aspects of the extremities. Genetic studies have identified mutations in the ADAR gene, encoding double-stranded RNA-specific adenosine deaminase, to be responsible for this disorder. Here, we found a novel deletion mutation in the ADAR gene, 2929delA, in a Chinese family with DSH. This mutation is located in codon 977 (AGC-->GC), and leads to a frameshift and truncated protein of 250 amino acids with 76 novel amino acids prior to a premature stop codon. The truncated ADAR is predicted to lack the ADEAMc (tRNA-specific and double-stranded RNA adenosine deaminase) domain. This study should be useful for genetic counseling and prenatal diagnosis for affected families and in expanding the database on ADAR gene mutations in DSH.

Identification of a novel mutation in the DSRAD gene in a Chinese pedigree with dyschromatosis symmetrica hereditaria

Dyschromatosis symmetrica hereditaria (DSH) is an autosomal dominant skin disorder characterized by a mixture of hyperpigmented and hypopigmented macules distributed on the face and dorsal aspects of the extremities that appear in infancy or early childhood. The DSH locus has recently been mapped to chromosome 1q21 and then pathogenic mutations have been identified in the DSRAD gene. In the study reported here we examined the DSRAD gene mutations of a three-generation Chinese pedigree with DSH by direct sequencing. We identified a novel heterozygous nucleotide T-->C transition at position 3388 in exon 14 of the DSRAD gene which induces a C1130R change in the putative deaminase domain of DSRAD. Our study expands the database on the DSRAD gene mutations in DSH and enriches the knowledge about the function of the DSRAD gene.

X-linked reticulate pigmentary disorder with systemic manifestations: report of a third family and literature review

Three siblings, two boys and one girl, presented with pigmentary abnormalities. The brothers, ages 11 and 6 years, had diffuse reticulate macular hyperpigmentation with onset in early childhood. In addition, these boys had hypohydrosis, coarse hair with an upswept frontal hairline, failure to thrive, and chronic pulmonary disease. The older boy also had corneal dystrophy and marked photophobia. A punch biopsy specimen from the 11-year-old showed melanophages and necrotic keratinocytes. Stains for amyloid were negative. The sister, age 2 years, had congenital linear hyperpigmented patches involving the intertrigenous areas, but was otherwise normal. The clinical findings of these children were consistent with X-linked reticulate pigmentary disorder with systemic manifestations. We present a summary of the clinical manifestations of this rare disorder and discuss efforts to identify the causative gene.

A new arginine substitution mutation of DSRAD gene in a Chinese family with dyschromatosis symmetrica hereditaria

BACKGROUND

Dyschromatosis symmetrica hereditaria (DSH) is a pigmentary genodermatosis of autosomal dominant inheritance characterized by a mixture of hyperpigmented and hypopigmented macules distributed on the dorsal aspects of the hands and feet. To date, only three articles testified that DSH is caused by the mutations of DSRAD gene (also called ADAR1) encoding for RNA-specific adenosine deaminase.

OBJECTIVE

To identify mutations of DSRAD as the disease-causing gene and recognize different mutations giving a clue to insight into the mechanism of DSH.

METHODS

We collected a Chinese DSH family consisting of a total of 11 individuals including five DSH patients (three males and two females). The whole coding region of DSRAD was amplified by polymerase chain reaction and products analyzed by direct sequencing.

RESULTS

We detected a transition, 3463 C>T, leading to a missense mutation (R1155W) in genomic DNAs of five patients, and the point mutation was not found in normal individuals in this DSH family and in 100 unrelated, population-match control individuals.

CONCLUSION

Our data suggests that R1155W missense mutation is a new mutation in exon 15 of DSRAD gene and further testify that DSRAD gene is the pathogenic gene of DSH.

A novel mutation of the DSRAD gene in a Chinese family with dyschromatosis symmetrica hereditaria

Dyschromatosis symmetrica hereditaria (DSH) is a pigmentary genodermatosis of autosomal dominant inheritance characterized by a mixture of hyperpigmented and hypopigmented macules distributed on the dorsal aspects of the hands and feet. It is caused by mutations of the RNA-specific adenosine deaminase gene. We report the identification of a Chinese family with a three-generation pedigree of DSH, in whom a novel tyrosine substitution mutation in DSRAD was demonstrated: a heterozygous nucleotide A-->G transition at position 2879 in exon 10 of the DSRAD gene was detected.

Reticulate acropigmentation of dohi: first case reports from Nepal

Acropigmentation of Dohi is a rare acropigmentary disorder. We report two cases of reticulate acropigmentation of Dohi from Nepal. To the best of our knowledge, these two cases represent the first case reports from Nepal.

A gene locus responsible for dyschromatosis symmetrica hereditaria (DSH) maps to chromosome 6q24.2-q25.2

Dyschromatosis symmetrica hereditaria (DSH) is a hereditary skin disease characterized by the presence of hyperpigmented and hypopigmented macules on extremities and face. The gene, or even its chromosomal location, for DSH has not yet been identified. In this study, two Chinese families with DSH were identified and subjected to a genomewide screen for linkage analysis. Two-point linkage analysis for pedigree A (maximum LOD score [Z(max)] = 7.28 at recombination fraction [theta] = 0.00) and pedigree B (Z(max) = 2.41 at theta = 0.00) mapped the locus for DSH in the two families to chromosome 6q. Subsequent multipoint analysis of the two families also provided additional support for the DSH gene being located within the region 6q24.2-q25.2, with Z(max) = 10.64. Haplotype analysis confined the locus within an interval of 10.2 Mbp, flanked by markers D6S1703 and D6S1708. The two families had no identical haplotype within the defined region, which suggests that the two families were different in origin. Further work on identification of the gene for DSH will open new avenues to exploration of the genetics of pigmentation.

Identification of a locus for dyschromatosis symmetrica hereditaria at chromosome 1q11-1q21

Dyschromatosis symmetrica hereditaria is a rare autosomal dominant cutaneous disorder characterized by a mixture of hyperpigmented and hypopigmented macules of various sizes on the face and the dorsal aspects of the extremities. The genetic basis for this disease is unknown. We performed a genome-wide search in two large Chinese families to map the chromosome location of the responsible gene. We identified a locus at chromosome 1q11-1q21 with a cumulative maximum two-point LOD score of 8.85 at marker D1S2343 (at recombination fraction=0.00). Haplotype analyses indicated that the disease gene is located within the 11.6 cM region between markers D1S2696 and D1S2635. This is the first locus identified for dyschromatosis symmetrica hereditaria. This study provides a map location for isolation of a disease gene causing dyschromatosis symmetrica hereditaria.