Amyloidosis cutis dyschromica in two female siblings: cases report

Case Report: Amyloidosis Cutis Dyschromica: Dermoscopy and Reflectance Confocal Microscopy and Gene Mutation Analysis of a Chinese Pedigree

Background: Amyloidosis cutis dyschromica (ACD) is a rare type of primary localized cutaneous amyloidosis. Non-invasive techniques can provide important clues for early diagnosis. Objectives: To highlight the characteristic imaging changes of ACD under dermoscopy and reflectance confocal microscopy (RCM), investigate gene mutations in a Chinese Han pedigree of ACD, and analyze the genotype-phenotype correlation. Methods: Dermoscopy and RCM examinations were completed together for the pedigree, and the imaging characteristics were described. The diagnosis of ACD was confirmed by pathological examination. Sequencing was performed followed by bioinformatics and genotype-phenotype correlation. ACD-related articles published on PubMed between January 1970 and March 2021 were reviewed and summarized. Results: In ACD, dermoscopy showed patchy white hypopigmentation and brownish spots, stripes, or hyperpigmented blotches and patches. RCM showed a highly refractive substance with clumpy, dotted, and linear structures inside the papillary dermis. Sequencing identified glycoprotein non-metastatic melanoma protein B (GPNMB) missense mutations [c.393T>G (p.Y131X; NM_001005340.2)] and a frameshift deletion mutation [c.719_720delTG (p.V240fs; NM_001005340.2)]. The ANNOtate VARiation (ANNOVAR) software predicted that c.393T>G is a pathogenic mutation. The literature review found 14 mutations, namely, 5 (35.7%) frameshift mutations, 4 (28.6%) non-sense mutations, 4 (28.6%) missense mutations, and 1 (7.1%) splice site mutation. Blisters and epidermolysis were observed in several cases, but there was no significant association between clinical manifestations and mutations in ACD. Conclusions: This study was the first to combine dermoscopy and RCM to describe ACD. Two GPNMB gene mutations were reported in a Chinese ACD pedigree. The genotype-phenotype correlation was analyzed for the first time; however, there was no significant correlation.

Two missense mutations in GPNMB cause autosomal recessive amyloidosis cutis dyschromica in the consanguineous pakistani families

BACKGROUND

Amyloidosis cutis dyschromica (ACD) is a rare variant of cutaneous amyloidosis. This disorder often clusters in families, and it has been suggested that genetic factors might be involved in its development.

OBJECTIVE

To identify the genetic causes of ACD, we recruited a consanguineous Pakistani family with multiple cases of ACD that display a recessive mode of inheritance.

METHODS

We performed whole-exome sequencing of samples from 7 members of this family, followed by bioinformatic and in silico analyses to identify the causative variant. For the replication study, we recruited a British family with Pakistani ancestry, and sequenced all exons of glycoprotein non-metastatic melanoma protein b (GPNMB) to identify mutations. We also investigated effects of the mutations on the stability of the GPNMB protein using the I-TASSER three-dimensional modeling tool.

RESULTS

We found a novel homozygous mutation, p.Gly363Val (c.1088 G>T), in GPNMB in all affected cases. In a replication study, another homozygous missense mutation in GPNMB, pIle174Met (c.522 C>G), was carried by the affected son. The two mutations were not observed in our in-house data set comprising 217 healthy Pakistani individuals or in The Genome Aggregation Database. Our structural modeling of GPNMB suggested that p.Gly363Val enhanced its stability, whereas p.Ile174Met caused instability.

CONCLUSIONS

This study reports two novel missense mutations in two Pakistani families that cause ACD. The mutations appear to influence GPNMB stability, as revealed by protein modeling.

Primary Localized Cutaneous Amyloidosis Affecting Female Individuals of a Pakistani Pedigree

Primary localized cutaneous amyloidosis is a group of rare conditions where amyloid deposition is limited to the skin without systemic manifestations. Most cases are sporadic; however, mutations in the oncostatin M receptor (OSMR) and interleukin-31 receptor A (IL31RA) genes can cause a familial form of the condition in up to 10% of cases. Here, we describe a family in which 8 female individuals are affected by either macular amyloidosis or amyloidosis cutis dyschromica. To the best of our knowledge, a sex-specific expression or the coexistence of 2 different phenotypes of primary localized cutaneous amyloidosis in 1 pedigree has not yet been reported.

Association of amyloidosis cutis dyschromica and familial Mediterranean fever

Amyloidosis cutis dyschromica is a rare type of primary cutaneous amyloidosis characterized by reticulate hyper-pigmentation with discrete hypopigmented macules. Up to date, about 50 cases of amyloidosis cutis dyschromica have been reported and the majority are familial cases of Asian ethnicity. Various diseases, particularly autoimmune diseases such as systemic sclerosis and systemic lupus erythematosus, have been associated with amyloidosis cutis dyschromica. Herein, we report a case of amyloidosis cutis dyschromica accompanying familial Mediterranean fever with a delayed diagnosis of 40 years. To the best of our knowledge, this is the first report of the association of amyloidosis cutis dyschromica and familial mediterranean fever.

Amyloidosis Cutis Dyschromica, a Rare Cause of Hyperpigmentation: A New Case and Literature Review

Amyloidosis cutis dyschromica is a rare form of primary cutaneous amyloidosis without systemic involvement and characterized by asymptomatic, progressive hyper- and hypopigmentation. We present the first case of a patient with amyloidosis cutis dyschromica diagnosed previously elsewhere as having Addison disease with generalized hyperpigmentation of the skin. This case suggests that in patients presenting with asymptomatic cutaneous dyschromia a skin biopsy for histopathological examination should be considered.

Amyloidosis Cutis Dyschromica: A Rare Reticulate Pigmentary Dermatosis

We are reporting a rare case of amyloidosis cutis dyschromica in a 41-year-old man. This is a rare form of primary cutaneous amyloidosis characterized by reticulate pigmentation with hypopigmented and hyperpigmented macules, onset in childhood, familial tendency in some, occasional mild itching and deposition of amyloid in the papillary dermis. Our case also had multiple bilaterally symmetrical hyperpigmented keratotic papules abutting the axillary vault resembling those seen in Dowling–Deogs disease. The other unusual feature in this patient was the strong family history of vitiligo, which we are unable to explain. We have also tried to explain the mechanism leading to the hyperpigmentation and hypopigmentation in amyloidosis cutis dyschromica.

Amyloidosis cutis dyschromica in two siblings and review of the epidemiology, clinical features and management in 48 cases

Amyloidosis cutis dyschromica (ACD) is a rare form of primary cutaneous amyloidosis (PCA). There is a paucity of information in the dermatology literature to guide its diagnosis, investigation and treatment. We present two siblings with ACD and summarise the epidemiology, clinical features, natural history and treatments in 48 cases of ACD from the literature. Familial cases were more common (37) than sporadic cases. ACD is predominantly reported in those of East and South-East Asian ethnicity (63%). The mean age of onset was 6 years in familial cases, and 23 years in sporadic cases. The clinical features of familial and sporadic ACD do not differ substantially. Pruritus was the only symptom, and was reported in 19% of all cases. There were no reported ACD cases with systemic amyloidosis. Acitretin was reported to result in improvement in seven of 10 patients treated. Routine investigation for systemic involvement is not necessary. Acitretin may be helpful.

Familial amyloidosis cutis dyschromica in three siblings: report from indonesia

Amyloidosis cutis dyschromica (ACD) is an extremely rare type of primary cutaneous amyloidosis. To date there are fewer than 40 published cases worldwide; some were reported affecting several family members. Its resemblance to other common pigmentation disorders makes it rarely recognized at first sight. Our patient, the 12-year-old firstborn son of non-consanguineous parents presented with generalized mottled pigmentation starting from lower extremities. His siblings suffered from similar condition. The clue for diagnosis is the amyloid deposition in the papillary dermis. The etiology of ACD is still unknown, but genetic factors and ultraviolet radiation are implicated. It is proposed that disturbance of keratinocyte repair following ultraviolet radiation results in amyloid deposition. The treatment remains a challenge. Oral acitretin treatment, thought to repair keratinization defect, gave a slight improvement in our case. Our is the first case of ACD reported in Indonesia.

Reticulate dermatoses

The term "reticulate" is used for clinical description of skin lesions that are configured in a net-like pattern. Many primary and secondary dermatoses present in such patterns involving specific body sites. Certain cutaneous manifestations of systemic diseases or genodermatoses also present in such manner. This review classifies and describes such conditions with reticulate lesions and briefly, their associated features.

Amyloidosis cutis dyschromica

Amyloidosis cutis dyschromica is a very rare form of primary cutaneous amyloidosis characterized by prepubertal onset of hyper and hypopigmented spots and amyloid deposits in the papillary dermis. We report a case of a 26 year old female with amyloidosis cutis dyschromica who presented with dyschromic skin since birth.

Amyloidosis cutis dyschromica

Background

Amyloidosis cutis dyschromica is a rarely documented variant of cutaneous amyloidosis. To date, only 26 cases have been reported.

Objective

The purpose of this study was to improve the clinical and histopathological data for this variant of amyloidosis and to highlight the immunohistochemical features of the disease. The published cases were also reviewed.

Methods

We performed a retrospective review of patients with amyloidosis cutis dyschromica in a single centre. The clinical, histopathological and immunohistochemical features were documented and analysed.

Observations

We described 10 cases of amyloidosis cutis dyschromica. Six of them were female. Five patients were from the same family, and the other 5 were sporadic. The distinguishing features of the clinical presentation included generalised mottled hyper- and hypopigmented macules, which were asymptomatic or mild pruritic. The typical onset of the lesions occurred in childhood (n = 7) and occasionally after puberty (n = 3). No evidence of systemic amyloidosis deposition was observed in these cases of amyloidosis cutis dyschromica. Amyloid deposits were observed in the papillary dermis and were positive for the Congo red stain. An immunohistochemical study showed that the amyloid expresses cytokeratins CK34βE12 and CK5/6.

Conclusions

We described the largest series of amyloidosis cutis dyschromica to date and reviewed the published patients. This rare disease is featured by generalised mottled hyper- and hypopigmented lesions, and it is a rare variant of primary cutaneous amyloidosis without evidence of systemic amyloid deposition. Positive staining for the cytokeratins CK34βE12 and CK5/6 in amyloidosis cutis dyschromica suggests that the amyloid is derived from keratinocytes.