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Disorders of Pigmentation
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Michael Joseph Lavery, Charles Cathcart, Hasan Aksoy
Differential diagnosis: Piebaldism is a rare autosomal dominant disorder due to mutation in the KIT-proto-oncogene. It is characterized by a white forelock and depigmented patches, which are commonly located on the forehead. The presence of a white forelock, a depigmented patch, sensorineural deafness, and iris heterochromia are consistent with Waardenburg’s syndrome. The differential diagnosis of localized hypopigmentation is summarized in Table 25.2.
Disorders of pigmentation
Published in Rashmi Sarkar, Anupam Das, Sumit Sethi, Concise Dermatology, 2021
There are several other types of albinism, most of which are recessive. In the Hermanski–Pudlak syndrome, there is an associated clotting defect due to a platelet abnormality. Patients have a bleeding tendency, interstitial pulmonary fibrosis, and granulomatous colitis. This is ‘tyrosinase positive’ and hair bulbs turn black after they are incubated with l-DOPA. Chediak–Higashi syndrome is characterized by severe immunodeficiency and silvery-white hair, and the histology is classical, showing giant melanosomes within melanocytes. Griscelli syndrome, on the other hand, is a severe immunological disorder with hemophagocytic syndrome in addition to having silvery-white hairs and pigmentary dilution of skin. Waardenburg syndrome is a distinct entity manifesting as achromia of skin, hairs, and eyes, heterochromia iridis, congenital deafness, broad nasal root, and dystopia canthorum. The hallmark finding in piebaldism is white forelock and the presence of normal skin within the depigmented patches.
Differential Diagnosis
Published in Vineet Relhan, Vijay Kumar Garg, Sneha Ghunawat, Khushbu Mahajan, Comprehensive Textbook on Vitiligo, 2020
Hemant Kumar Kar, Gunjan Verma
Piebaldism is a rare autosomal dominant disorder with an underlying defect of the tyrosine kinase transmembrane receptor on melanocytes, leading to impaired embryonic migration and survival of melanocytes in the skin. It results from a mutation in the c-kit proto-oncogene, mapped to the proximal long arm of chromosome 4 (4q12) or from deletions in the SLUG gene, which is a zinc finger neural crest transcription factor. Recently reported cases of piebaldism, which are milder or more severe than genetically expected, indicate that other factors (e.g., a modifier gene of MC1R) influence skin and hair color [5]. Piebaldism is clinically characterized by congenital extensive, symmetrically distributed depigmentation mainly on the forehead, front of the thorax, and extremities [5]. The extent of the lesions is variable, ranging from only a midfrontal poliosis or white forelock (present in 80%–90% of patients) and minimal areas of depigmentation to depigmentation of almost the entire body and hair (Figure 16.1b). Sometimes in the early age group and in initial stages it is hard to differentiate between piebaldism and segmental vitiligo having leukotrichia. However, a normal area of skin in between depigmented skin is the hallmark sign of piebaldism.
Outcomes of autologous non-cultured melanocyte keratinocyte transplantation in vitiligo and nevus depigmentosus
Published in Journal of Dermatological Treatment, 2022
Thanyanan Sritanyarat, Chanisada Wongpraparut, Natchaya Jansuwan, Punyanut Yothachai, Nuttaporn Nuntawisuttiwong, Narumol Silpa-archa
MKTP was also shown to be efficacious for the treatment of other leukodermas, such as nevus depigmentosus and piebaldism. For nevus depigmentosus, Mulekar, et al. (9) demonstrated good repigmentation ranging from 80–100% in 3 cases, while 2 other cases had a poor response. However, color mismatch was observed in 2 of the 3 cases that responded to the treatment. van Geel N, et al. (25) reported a single case that had 78% improvement, while Olsson, et al. (26) reported a poor response to treatment in one case. Our study found a good response in three cases of nevus depigmentosus at both the short- and long-term follow-ups.
Novel retinal finding in a patient with 4q12 deletion
Published in Ophthalmic Genetics, 2022
Mario Fruschelli, Nicola Lorusso, Theodora Hadjistilianou, Maria Antonietta Mencarelli, Mirella Bruttini, Alessandra Renieri, Marco Mandalà, Alessandro Di Maggio
Although rare, several ocular findings have been described in patients affected by proximal 4q deletions. Structural ocular anomalies, such as microphthalmia, coloboma and high myopia, have been related to haploinsufficiency for BMP3 and BMP2K genes, codifying a group of pivotal morphogenetic growth factors (1). The deletion reported in our patient however resulted in smaller than previously reported and did not include these genes. Pigmentary changes, such as blue sclerae or pigment retinal clumps, may be related to c-Kit mutations (2,3). Mutations in the c-kit proto-oncogene are responsible for piebaldism, a rare autosomal dominant genodermatosis characterized by the presence of symmetrically distributed, persistent, patches of skin hypo- or depigmentation, caused by congenital absence of melanocytes, usually associated with congenital white forelock (4,5). Piebaldism is part of a wide spectrum of diseases known as auditory-pigmentary disorders (APDs), also including Waardenburg syndrome, oculocutaneous albinism, and Tietz syndrome. All APDs share common clinical features, such as skin and hair pigmentary anomalies, which can be associated with a broad spectrum of ocular, auditory, and neurological disorders. Considering that the association between heterozygous loss-of-function KIT mutations and piebaldism is well established and intellectual disability or developmental delay is frequently observed in individuals with a proximal 4q deletion, skin, and neurological features of our patient can be explained by haploinsufficiency for this genomic region. Although the retinal findings herein reported have never been described before in patients affected by 4q12 deletion, we do not exclude that they could represent a manifestation of the peculiar genetic asset of the patient, related to dysfunction in pigment epithelium/neuroretinal metabolic activity.