BACKGROUND: Piebaldism is a rare autosomal dominant disorder characterized by congenital white forelock and depigmented patches, which is most commonly caused by deleterious variants in the KIT gene.
METHODS: Four KIT variants were identified in a piebaldism case series by whole-exome sequencing. Functional experiments, including in vitro minigene reporter assay and enzyme-linked immunosorbent assay, were carried out to elucidate the pathogenicity of the variants. The genotype-phenotype correlation was summarized through extensive literature reviewing.
RESULTS: All the four cases had severe piebaldism presented with typical white forelock and diffuse depigmentation on the ventral trunk and limbs. Four germline variants at the tyrosine kinase (TK) domains of the KIT gene were identified: two novel variants c.1990+1G>A (p.Pro627_Gly664delinsArg) and c.2716T>C (p.Cys906Arg), and two known variants c.1879+1G>A (p.Gly592_Pro627delinsAla) and c.1747G>A (p.Glu583Lys). Both splicing variants caused exon skipping and inframe deletions in the TK1 domain. The missense variants resided at the TK1 and TK2 domains respectively impairing PI3K/AKT and MAPK/ERK signaling pathways, the downstream of KIT. All severe cases were associated with variants in the TK domains, eliciting a major dominant-negative mechanism of the disease.
CONCLUSIONS: Our data expand the mutation spectrum of KIT, emphasized by a dominant-negative effect of variants in the critical TK domains in severe cases. We also share the experience of prenatal diagnosis and informed reproductive choices for the affected families.

OBJECTIVE: To compare the efficacy and safety of autologous cultured melanocytes transplantation (CMT) and non-cultured epidermal cell suspension transplantation (NCES) in the treatment of piebaldism.
METHODS: A retrospective study was conducted on 30 anatomically based lesions from nine piebaldism patients who underwent either CMT (n = 7) or NCES (n = 23) between 2018 and 2020. The extent of repigmentation and colour matching was evaluated in all recipient sites using a digital imaging analysis system. In addition, adverse effects have also been assessed by follow-up results.
RESULTS: More than 75% repigmentation was achieved in 100% (7/7) and 60.9% (14/23) of the 30 lesions with the CMT and NCES, respectively. There were significant differences between the two methods in terms of repigmentation. The majority of patients had colour mismatches, and there was no discernible difference between the two surgical techniques. Adverse reactions rarely occurred.
CONCLUSIONS: The present study suggested that autologous CMT may provide better repigmentation in piebaldism patients than NCES with no significant side effects.

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Ataxia cerebelosa aguda en el síndrome de Griscelli de tipo 2.

BACKGROUND: Piebaldism is the dominantly inherited skin disorder clinically characterized by congenital stable and well circumscribed patches of leukoderma (depigmented skin) of ventral distribution, involving central forehead, frontal chest and abdomen and central portion of limbs, and by localized poliosis (white hair). Inherited or de novo mutations in proto-oncogene KIT, encoding the transmembrane tyrosine kinase receptor c-kit, underly the majority of piebaldism cases. Piebaldism is a disorder characterized by incomplete penetrance and variable expressivity.

BACKGROUND: Piebaldism is a rare, autosomal dominant, and congenital pigmentary disorder characterized by stable depigmentation of the skin and white forelock. Mutations in KIT or SLUG genes result in piebaldism. Most individuals with piebaldism have a family history of the disorder.
METHODS: In this paper, we report a case of piebaldism with café-au-lait macules resulting from a novel mutation of KIT gene c.1982C > T (p.Thr661Ile) in a three-generation Chinese family. The whole-exome sequencing, mitochondrial gene 3000X, and bioinformatics tools were used to identify the mutation in this new-found pedigree. In addition, we searched the databases of \"Punmed, Chinese National Knowledge Infrastructure, CMJD, WANFANG MED ONLINE\", reviewed 88 cases of piebaldism caused by KIT gene mutation, and summarized the relationship between clinical phenotype and genotype of piebaldism through logistic regression and other statistical methods.
RESULTS: The proband and her affected mother carried a heterozygous c.1982C > T missense mutation (p.Thr661Ile) on KIT gene. Bioinformatics analysis hinted that it had potential pathogenicity. The data showed that piebaldism patients with cafè-au-lait macules had KIT mutations almost located in the intracellular tyrosine kinase domain and were mostly related to the severe clinical phenotype of piebaldism.
CONCLUSIONS: The new heterozygous c.1982C > T missense mutation on KIT caused piebaldism with café-au-lait macules in this Chinese family. This study provides a new reference index for clinicians to judge the severity of clinical phenotypes of piebaldism, broadens the understanding of the correlation between clinical phenotypes and genotypes of piebaldism, and provides reference of genetic counseling and prenatal diagnosis for affected families.

BACKGROUND: The autologous noncultured melanocyte keratinocyte transplant procedure (MKTP) has emerged as a popular grafting technique with proven efficacy for achieving repigmentation. However, there remains no consensus regarding the optimal recipient-to-donor (RD) ratio required to achieve acceptable repigmentation. In this retrospective cohort study of 120 patients, we sought to examine whether expansion ratios impact the repigmentation success rates following MKTP.
RESULTS: A total of 69 patients (mean [SD] age was 32.4 [14.3] years, mean follow-up was 30.4 [22.5] months, 63.8% were male; 55% were dark-skinned individuals [Fitzpatrick IV-VI]) were included. The mean percent change in the Vitiligo Area Scoring Index (VASI) was 80.2 (±23.7; RD of 7.3) in patients with focal/segmental vitiligo (SV), 58.3 (±33.0; RD of 8.2) in those with non-segmental vitiligo (NSV), and 51.8 (±33.6; RD of 3.7) in those with leukoderma and piebaldism. Focal/SV was positively associated with a higher percent change in VASI (parameter estimate: 22.6, p value <0.005). In the SV/focal group, non-white patients had a higher RD ratio compared to White individuals (8.2 ± 3.4 vs. 6.0 ± 3.1, respectively, p value = 0.035).
CONCLUSIONS: In our study, we found that patients with SV were significantly more likely to achieve higher repigmentation rates compared to those with NSV. Although repigmentation rates were higher in the low expansion ratio group than in the high expansion ratio group, we did not observe a significant difference between the two groups.
CONCLUSIONS: MKTP is an effective therapy for restoring repigmentation in patients with stable vitiligo. Therapeutic response of vitiligo to MKTP appears to be influenced by the type of vitiligo, rather than a specific RD ratio.

We report the first case of partial albinism in the Critically Endangered angelshark, Squatina squatina. The encounter with this specimen took place while SCUBA diving on the beach of Tufia, located on the east coast of the island of Gran Canaria on 2 April 2021. This is also the first confirmed finding of an albino elasmobranch specimen in the Canary Island archipelago.

Piebaldism is a rare genetic disorder of congenital leukoderma caused by mutation in KIT proto-oncogene receptor tyrosine kinase. We present a 10-year-old boy with congenital depigmented macules suggestive of piebaldism associated with café au lait macules and skin fold freckling complicating the diagnosis. A diagnosis of piebaldism was made via exome sequencing that showed a pathogenic variant of KIT gene with no pathogenic variants of NF1 or SPRED1 gene. Our current understanding of the KIT tyrosine kinase function may provide a better explanation into this phenotypic coexistence and does not necessarily represent an overlap with Neurofibromatosis type 1.