Mosaic Pigment – Choosing the Right Shade
Mosaic pigment is used by artists all over the world in a variety of ways. It is often used as a filler to add colour to the background of a tile, and it can also be used to highlight individual elements of the design. There are many different shades available, so choosing the right one can be tricky. In this article we will look at some of the key factors to consider when choosing the perfect shade.
Phylloid
Pigmentary mosaicism (PM) is a genetically inherited disorder of pigmentation. It is characterized by patterned hypo- or hyperpigmentation. These abnormalities have a variety of clinical expressions. Most commonly, PM shows a pattern of irregular dyspigmentation along Blaschko lines.
In addition, patients with PM may present with other mosaic patterns. They can include whorled nevoid hypermelanosis and phylloid hypermelanosis. Hypomelanosis of the Ito type is also considered a form of PM. This is a mosaic of hyperpigmented and hypopigmented whorls and streaks.
Phylloid hypermelanosis is a rare form of pigmentary mosaicism. This pattern of cutaneous dyspigmentation is characterized by hyperchromic and hypochromic lesions. Some patients with this condition have been associated with a choroidal coloboma and conductive hearing loss.
Phylloid hypermelanosis has a complex clinical picture and the cause is unclear. One study described a 29-year-old man with mental deficiency who presented with hypermelanotic macules arranged in a phylloid pattern. Another report cited a case of phylloid hypermelanosis in a patient with cicatricial alopecia.
Although the specific genetic mutation in this case has not been identified, it is believed that it occurs on the P gene. The P gene has been implicated in cases of PM with cytogenetic abnormalities involving 15q.
Other cases of phylloid hypermelanosis have been reported in the literature. A patient with a chromosomal mutation of t(13;13) had a mosaic pattern of phylloid hypermelanosis.
Cytogenetic analysis has been performed on the fibroblasts from these patients. These cells showed three aberrant cell types. Almost any chromosome can be affected. However, most chromosomal mosaicism is tissue-limited, meaning that the cytogenetic alteration is not detectable by routine laboratory testing.
Various hypothesis have been proposed to explain abnormal pigmentation. A phenotypic reversion has been suggested as a possible explanation. Additional patients with clinical research will enable researchers to identify the pigmentation-associated genes.
Patients with PM typically present with abnormal pigmentation in the first year of life. The skin changes are usually reversible without dermatological therapy. But the presence of extracutaneous abnormalities, such as hearing loss, is a factor that increases the risk of a poor prognosis.
Checkerboard
It’s not often that we get to see a well groomed specimen with all the trimmings. Thankfully, we can do a little bit of ogling on the other side of the fence with a click of a button or two. The best part about being able to ogle a specimen on the fly? Not only are we spared the hassle of grooming the halo, but our eminently groomed specimens are tame to boot. That is, as long as we get some downtime to do Mosaic Pigment a lil’ bit of maintenance. If we are lucky, we might even get to see our mates and kin on the flipside. Best of all, it’s all for free. We might just be able to see a tuxedo in our follicles at last!
Patchy
One of the most common forms of chromosomal mosaicism is a patchy pattern of hyper- or hypo-pigmentation. This phenotype can cause various complications. Typically, it is present on the skin but may manifest as an extracutaneous anomaly. Some patients may also present with other patterns of pigmentation.
The best way to determine whether a particular patient is affected by this phenotype is to perform a thorough physical exam. A careful assessment should look for subtle to moderate asymmetries. Other signs of a mosaic phenotype may include a syndactylotic pattern, an asymmetry of the limbs, or a checkerboard pattern.
In addition to the most obvious phenotypes, a number of other disorders are known to occur in conjunction with a mosaic phenotype. These maladies have been reported in children and adults alike. However, the term mosaicism has not been specifically defined for all of these conditions. It has been suggested that mosaicism is more of an umbrella term for all of the pigmentary anomalies that result from chromosomal mosaicism.
The most important thing to remember about mosaicism is that it is not a single phenotype. In fact, it is a complex network of disorders. Each symptom is associated with its own underlying cause and can be categorized into different types. Most commonly, pigmentary mosaicism is associated with learning difficulties, microcephaly, and other neurological deficits.
Other conditions that are part of the broader mosaic phenotype include McCune Albright syndrome and the CHILD syndrome. In the case of the former, the most obvious symptom is a lateralization pattern. Also, the aforementioned chimerical flutter may actually be a real thing.
While most cutaneous mosaicism phenotypes are sporadically encountered, they are not without their own set of complications. Hyperpigmentation, for example, has been linked to chromosome 13 abnormalities. Similarly, the aforementioned flutter may be a sign of functional loss or acquisition of one or more chromosomes.
Finally, a recent study has confirmed the association between a patchy pattern of hyper- or a hypo-pigmented skin and HOG. Though the study did not provide data for the population of women and men living with the aforementioned condition, the results did show that the aforementioned was more common in those with mosaic phenotypes.
Blaschko
Blaschko mosaicism is a rare chromosomal disorder characterized by hyperpigmented and hypopigmented patterns of skin. It is a clone of two or more Mosaic Pigment skin cells that produce different amounts of melanin. These cell lines are arranged in a checkerboard pattern. Pigmentary mosaicism may be accompanied by neurological or systemic disorders.
Most patients with a Blaschko pigmentation pattern have a linear or a block-like configuration. Other patterns include a leaf-like arrangement, a phylloid pattern, or a segmental distribution. In addition to clinical signs, these patterns also indicate genetic etiologies.
The most common clinical pattern involves narrow bands of skin following Blaschko’s lines. This pattern is usually associated with a phylloid or segmental distribution of melanocytes. A phylloid pattern is one with uniformly pigmented dark brown macules. Their irregular margins may spare nails, hair, mucosae, or the eyes.
Another manifestation is hyperpigmented whorls and streaks. This type of hypermelanosis is also called whorled nevoid hypermelanosis. Unlike phylloid and segmental patterns, whorled and linear nevoid hypermelanosis is characterized by a hyperpigmented and hypopigmented pattern.
The diagnosis of Blaschko mosaicism should be based on clinical examination, but the diagnosis should be confirmed by a thorough cytogenetic investigation. Cytogenetic analysis should include a karyotype from a biopsy of skin. If no normal cell line can be found, a biopsy from both the skin types should be performed. Although most cytogenetic studies have used cultured fibroblasts, results from normal cell lines are rarely seen in mosaic individuals.
Various forms of overgrowth can occur in the Proteus syndrome. This condition can be diagnosed if the patient has an abnormal AKT1 gene, which produces a growth-activating protein. Naevi may be present as well. Moreover, naevi and other cutaneous abnormalities may be evident in patients with a pigmentary karyotype.
An asymptomatic case of a 6-year-old girl presented with a phylloid pattern of skin with a hyperpigmented pattern of lines. She also had a mild mental retardation and a bupthalmos of the left eye. Her chromosomal karyotype was 45,X. Cultured skin fibroblasts were found to contain 47,XX,+7 cells.
