Mosaic pigment is a type of dyspigmentation that occurs as a result of a genetic change during postzygotic development. It affects daughter cells in skin and other organs. If the daughter cells migrate outside the skin, extracutaneous manifestations can develop. The extent of involvement in the skin is greater if the underlying genetic event occurred earlier in embryogenesis.

Dyspigmentation

A patient with mosaic pigment (PM) presents with cutaneous dyspigmentation characterized by hypo and hyper-pigmentation of the skin. It usually occurs in one region but rarely occurs in both regions. The pigmentary pattern is most commonly along Blaschko lines, although other mosaic patterns may also occur. These lesions can be detected with Wood’s light.

Currently, there are few published studies on this disorder. In 1983, Metzker and colleagues described it as a distinct entity. This is a rare but significant condition characterized by patterned hypo and hyperpigmented patches. This disorder is hereditary, and is more likely to affect the trunk than the face. It is often mistaken for mosaic pigment disorder, but if you have the symptoms of mosaic pigment, segmental hypopigmentation could be present.

Symptomatic patients with mosaic pigment disorder may have other symptoms, including a distinct facial pattern. They may also have a variety of birthmarks. The majority of patients may have a combination of skin and hair hypopigmentation. Patients with mosaic pigment disorder are typically affected in their first year of life. They may also have unique mutations in known or unknown genes. This article reviews the current status of treatment options for this condition.

Genetic studies have shown that there are several genes involved in mosaic pigmentation. These genes control the pigment’s distribution in different areas of the body. Other genes, such as s and W, play a role in determining the degree of spotting. Genetic studies have shown that pigment genes often interact in synergistic ways. Similarly, a double heterozygote of Ph and Wv is likely to display mid-ventral spotting.

Genetic studies have revealed numerous pigmentary genes in mice. Several of these genes have human homologues. HI patients show decreased melanocyte counts and defective pigment production. In addition, melanocytes may have fewer dendrites and small premelanosomes. Additionally, nerve endings in contact with melanocytes are increased in these patients.

Patients with mosaic pigment disorder may undergo genetic testing to diagnose the condition. Genetic tests of affected skin tissues can reveal somatic mutations that can explain the disease.

Diagnosis

Identifying and evaluating mosaic pigment in children requires careful clinical assessment. It requires the use of photographs of the physical findings at baseline and current time of diagnosis. The history and physical examination also must determine whether the disease is extracutaneous, i.e., if the pigmented lesions have any extracutaneous findings. The patient is also assessed for family history and for changes in size over time. The patient’s personal coping style is also assessed.

The clinical presentation of mosaic pigment varies among patients. While the majority of patients have skin abnormalities, a subset of individuals also manifest neurologic abnormalities. The spectrum of pigmentary mosaicism encompasses several clinical subtypes, with some authors limiting the diagnosis to those with extracutaneous manifestations.

Patients with cutaneous mosaic pigment are evaluated by dermatologists and clinical geneticists, as part of a nationwide collaborative effort. Patients must have cutaneous and extracutaneous manifestations and demonstrate a mosaic pattern. Patients with a postzygotic MTOR mutation, Waardenburg syndrome, or lichen striatus were excluded from the study.

Occasionally, patients with pigmentary mosaicism will have an accompanying family history. In one study, two paternal half-brothers of patients with hyperpigmented pigmentary mosaicism were found to have chromosomal mosaicism. However, in the other patient, chromosomal mosaicism was not detected in lymphocytes. This suggests that the prevalence of mosaic pigment is likely under-reported in the literature.

Diagnosis of mosaic pigment requires careful analysis of peripheral blood lymphocytes and fibroblasts. If the chromosomal mosaicism is not present, the diagnosis can be ruled out, but the phenotypic mosaicism may still exist. Moreover, mosaicism can cause minimal effects on a person’s phenotype and can explain other clinical findings or unusual modes of inheritance. DNA testing is commonly performed using blood cells, but it is essential to test other tissues for mosaic pigment as well.

Diagnosis of mosaic pigment is crucial to ensure a proper treatment. However, it can be difficult to determine whether a patient has the disorder. The disease affects all parts of the body. In 516 patients, dyspigmentation was predominantly Blaschkoid, with only a small minority exhibiting a phylloid or sash-like pattern. In addition, there were two patients with a combination of both patterns, and three patients did not report their distribution patterns.

Treatment

Pigmentary mosaicism is a type of patterned hyperpigmentation or hypopigmentation resulting from a clone of skin cells with altered ability to produce melanin. There are three main clinical patterns: streaks and swirls following Blaschko lines, segmental distribution, and leaf-like arrangement. This disorder can be either acquired or inherited.

Most patients with pigmentary mosaicism are affected sporadically. However, 4% of patients have a family history of the disorder. In one case, two paternal half-brothers were affected, and one of them had an underlying chromosomal disorder. The other patient did not have a family history of pigmentary mosaicism.

Genetic testing may reveal the cause of mosaicism. This test can be performed on affected tissue by using whole-exome sequencing. Genetic testing for mosaicism involves comparing the genomes of two populations of cells. This will help the doctor determine if a particular genetic defect or a certain type of gene is the cause of the disease.

A cytogenetic evaluation of peripheral blood lymphocytes and skin fibroblasts is recommended in suspected cases of pigmentary mosaicism. The chromosome analysis should include a substantial number of metaphases from the normal and affected skin. For a more thorough analysis, chromosome microarray analysis may be performed.

In addition to addressing the underlying cause of the disorder, the Mosaic Hair Clinic also provides a customized treatment plan. Their medical-grade pigments are specifically made for this treatment. The pigments are applied to the epidermis layer of the scalp. The clinic uses a precision machine sourced from Germany, which allows for a precise micropigmentation.

Because mosaicism is a genetic disorder, genetic screening may not be able to identify the exact cause. However, preimplantation genetic screening of fertilized eggs may identify if a mosaicism patient is likely to be born. If genetic screening is done for IVF, a woman should discuss her concerns with the fertility doctor. There are several risks associated with mosaicism, such as decreased testosterone, which may affect sexual development.

Patients with Pallister-Killian mosaic syndrome have severe to profound intellectual disability, and their skin pigmentation may be affected in various parts of their body. The face may be pale or red, and the hair may be sparse. Patients with the syndrome also develop other developmental problems.

Extracutaneous manifestations

Extracutaneous manifestations of mosaic pigment are uncommon, but they do occur in a few cases. The most common symptoms are skeletal deformities, dysmorphic facial features, and developmental delay. These manifestations may be a sign of an underlying mosaic state or be symptoms of another disorder.

Pigmentary mosaicism is a disorder in which daughter cells have different levels of pigmentation. The daughter cells are usually found in the skin, but can also be present in other organs. In some cases, these daughter cells migrate to other tissues, resulting in extracutaneous manifestations. The extent of extracutaneous involvement is usually greater when the causal genetic event occurred earlier in embryogenesis.

Pigmentary mosaicism can be inherited or acquired. It is characterized by a clonal pattern of skin cells with varying abilities to produce melanin. Most patients have a streak or swirl pattern that is sparse on the mucous membranes, palms, and soles. Patients usually first notice symptoms within the first year of life.

During the diagnosis of mosaic pigment, patients should undergo cytogenetic analysis. This is important because if the disease does not present any extracutaneous manifestations, it may be a result of an earlier disease onset. However, patients with extracutaneous manifestations should undergo peripheral blood lymphocytes analysis to confirm the diagnosis.

Trisomy 20 mosaicism is associated with a wide variety of extracutaneous manifestations, including renal abnormalities, hypermelanosis of Ito, and skeletal abnormalities. It has been associated with other symptoms, including neurocutaneous pathology and cardiac abnormalities. Although the disease may affect a patient’s lifespan, it is associated with a favorable prognosis.

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