Comparative outcomes of autologous cultured melanocytes transplantation and non-cultured epidermal cell suspension transplantation in piebaldism patients: A retrospective study.

PURPOSE: 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. PATIENTS AND 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. CONCLUSION: The present study suggested that autologous CMT may provide better repigmentation in piebaldism patients than NCES with no significant side effects.

[Acute cerebellar ataxia in Griscelli syndrome type 2]. / Ataxia cerebelosa aguda en el síndrome de Griscelli de tipo 2.

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

[MULTIPLE CAFÉ-AU-LAIT MACULES AND INTERTRIGINOUS FRECKLING: BEYOND THE RASOPATHIES].

INTRODUCTION: 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.

Piebaldism with café-au-lait macules resulting from a novel mutation of KIT gene in a three-generation Chinese family.

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. CONCLUSION: 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.

First record of partial albinism in the critically endangered Angelshark (Squatina squatina) (Linnaeus, 1758).

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.

Recipient-to-Donor Ratios in the Surgical Treatment of Vitiligo, Leukoderma, and Piebaldism: A Retrospective Review.

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). DISCUSSION: 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. CONCLUSION: 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.

Griscelli syndrome type 1: a novel pathogenic variant, and review of literature.

Griscelli syndrome type 1 (GS1) is a rare inherited autosomal recessive disease caused by a deleterious variant in the MYO5A gene and characterized by general hypopigmentation, neurological symptoms, motor disability, hypotonia, and vision abnormality. Only nine pathogenic variants in the MYO5A gene have been confirmed in association with the GS1. All of the reported pathogenic variants are truncating. Herein, two siblings from a consanguineous Iranian family with abnormal pigmentation and neurological symptoms were referred for genetic counseling. Whole-exome sequencing (WES) revealed a novel homozygous truncating variant c.1633_1634delAA (p.Asn545Glnfs*10) in the MYO5A gene, which was completely co-segregated with the phenotype in all affected and unaffected family members. Computational analysis and protein modeling demonstrated the deleterious effects of this variant on the structure and function of the protein. The variant, according to ACMG guidelines, was classified as pathogenic. Besides the novelty of the identified variant, our patients manifested more severe clinical symptoms and presented distal hyperlaxity in all four limbs, which was a new finding. In conclusion, we expanded the mutational and phenotypic spectrum of the GS1. Moreover, by studying clinical manifestations in all molecularly confirmed reported cases, provided a comprehensive overview of clinical presentation, and attempted to find a genotype-phenotype correlation.

Piebaldism and chromatophore development in reptiles are linked to the tfec gene.

Reptiles display great diversity in color and pattern, yet much of what we know about vertebrate coloration comes from classic model species such as the mouse and zebrafish.1,2,3,4 Captive-bred ball pythons (Python regius) exhibit a remarkable degree of color and pattern variation. Despite the wide range of Mendelian color phenotypes available in the pet trade, ball pythons remain an overlooked species in pigmentation research. Here, we investigate the genetic basis of the recessive piebald phenotype, a pattern defect characterized by patches of unpigmented skin (leucoderma). We performed whole-genome sequencing and used a case-control approach to discover a nonsense mutation in the gene encoding the transcription factor tfec, implicating this gene in the leucodermic patches in ball pythons. We functionally validated tfec in a lizard model (Anolis sagrei) using the gene editing CRISPR/Cas9 system and TEM imaging of skin. Our findings show that reading frame mutations in tfec affect coloration and lead to a loss of iridophores in Anolis, indicating that tfec is required for chromatophore development. This study highlights the value of captive-bred ball pythons as a model species for accelerating discoveries on the genetic basis of vertebrate coloration.

The investigation on allelic, genotypic frequencies and gene expression study in coding region of tyrosinase gene in Deoni cattle breed of western India.

An investigation was carried out on Deoni animals of western India to study the allelic and genotypic frequencies in coding region of TYR gene as well as gene expression profile. The animals were grouped according to age, gender, strain and intensity of partial albinism (low, medium and high). The present study revealed that the genotypic frequency of TYR gene across different strains, gender, age group and level of partial albinism was found to be non-significant for both exon-I and exon-II. The AB genotype in Balankya (0.70) was observed highest genotypic frequency followed by Wanera (0.55) and Shewara (0.55) strains. The genotypic frequency of AB and BB genotypes were observed highest in male and female, respectively. In exon-I, genotype frequency of AA genotype was found highest (0.55) in low level of partial albinism. The allelic frequencies in Shewara strain, male and low level of partial albinism were 0.75, 0.63 and 0.73, respectively. However, in exon-II genotype frequency of AB and BB was observed highest (0.70) in Wanera and Balankya strains followed by AA genotype in Shewara (0.50). The highest genotypic frequency of AA (0.87) and BB (0.50) were in male and female, respectively. The genotype frequency of AB genotype was found highest in all level of partial albinism. The allelic frequency was highest (0.85 for B allele) in Wanera strain, male (0.80 for A allele) and high level (0.60 for A allele) of particle albinism. The highly significant (p = 0.002) expression of tyrosinase gene was observed in young animals as compared to adult animals. The TYR gene expression was significantly (p = 0.047) higher in animals with low intensity of partial albinism followed by in the animals with medium and high intensity. Therefore, it is inferred that the TYR gene expression in young animals were high and as compared to the old animals of Deoni cattle breed.

Observations of hypomelanosis in the nurse shark Ginglymostoma cirratum.

Hypomelanosis refers to a suite of skin pigment abnormalities, including albinism, leucism and piebaldism. While documented across many vertebrate species, examples of hypomelanosis are rarely seen in chondrichthyans, with little insight into the potential effects on survival. Here, we report the first observation of abnormal skin pigmentation indicative of piebaldism in the Atlantic nurse shark Ginglymostoma cirratum, representing only the second reported case of skin aberrations for this species. This extremely rare observation is discussed in the broader context of fitness variation and long-term survival.

Oculo-Cutaneous Albinism Type 4 (OCA4): Phenotype-Genotype Correlation.

Albinism is a genetic disorder, present worldwide, caused by mutations in genes affecting melanin production or transport in the skin, hair and eyes. To date, mutations in at least 20 different genes have been identified. Oculo-cutaneous Albinism type IV (OCA4) is the most frequent form in Asia but has been reported in all populations, including Europeans. Little is known about the genotype-phenotype correlation. We identified two main phenotypes via the analysis of 30 OCA4 patients with a molecularly proven diagnosis. The first, found in 20 patients, is clinically indistinguishable from the classical OCA1 phenotype. The genotype-to-phenotype correlation suggests that this phenotype is associated with homozygous or compound heterozygous nonsense or deletion variants with frameshift leading to translation interruption in the SLC45A2 gene. The second phenotype, found in 10 patients, is characterized by very mild hypopigmentation of the hair (light brown or even dark hair) and skin that is similar to the general population. In this group, visual acuity is variable, but it can be subnormal, foveal hypoplasia can be low grade or even normal, and nystagmus may be lacking. These mild to moderate phenotypes are associated with at least one missense mutation in SLC45A2.

Neonatal Onset of Hemophagocytic Lymphohistiocytosis Due to Prenatal Varicella-Zoster Infection in a Neonate with Griscelli Syndrome Type 2.

Type 2 Griscelli syndrome (Type2 GS) is a primary inborn error of the immune system, classified in the immune dysregulation group.1,2 There are three different types of the disease, with different genetic causes responsible for the autosomal recessive inheritance pattern. Although hypopigmentation is common in all variants, neurological involvement or immunodeficiency with varying severity is seen in different types. Molecular motor protein myosin 5 an (MYo5A) [Type1GS], guanosine Triphosphate (GTP) binding protein (RAB27A) [Type2GS], and mutation in human melanophilin (MLPH) [Type 3GS] which is limited to hypopigmentation are reported as the known genetic defects in GS.3 Severe, ineffective, and uncontrolled inflammatory reactions are referred to as the pathogenesis of Hemophagocytic lymphohistiocytosis (HLH). HLH is a life-threatening condition that can be defined as either primary or secondary. Secondary causes happen in the context of autoimmunity, malignancy, spontaneous, or infections.4 Prenatal infections play an important role in causing long-term complications in the fetus. Some of them include toxoplasmosis, rubella, cytomegalovirus, herpes simplex, and other organisms including syphilis, parvovirus, and Varicella zoster, known as TORCH syndrome (5).TORCH has been well described for a long time but there are limited reports of developing HLH in the context of prenatal infections. We described a type 2GS syndrome with neonatal-onset HLH triggered by a prenatal infection.

Assessing the Activation of Tyrosine Kinase KIT through Free Energy Calculations.

KIT is a type 3 receptor tyrosine kinase that plays a crucial role in cellular growth and proliferation. Mutations in KIT can dysregulate its active-inactive equilibrium. Activating mutations drive cancer growth, while deactivating mutations result in the loss of skin and hair pigmentation in a disease known as piebaldism. Here, we propose a method based on molecular dynamics and free energy calculations to predict the functional effect of KIT mutations. Our calculations may have important clinical implications by defining the functional significance of previously uncharacterized KIT mutations and guiding targeted therapy.

Biallelic KITLG variants lead to a distinct spectrum of hypomelanosis and sensorineural hearing loss.

BACKGROUND: Pathogenic variants in KITLG, a crucial protein involved in pigmentation and neural crest cell migration, cause non-syndromic hearing loss, Waardenburg syndrome type 2, familial progressive hyperpigmentation and familial progressive hyper- and hypopigmentation, all of which are inherited in an autosomal dominant manner. OBJECTIVES: To describe the genotypic and clinical spectrum of biallelic KITLG-variants. METHODS: We used a genotype-first approach through the GeneMatcher data sharing platform to collect individuals with biallelic KITLG variants and reviewed the literature for overlapping reports. RESULTS: We describe the first case series with biallelic KITLG variants; we expand the known hypomelanosis spectrum to include a 'sock-and-glove-like', symmetric distribution, progressive repigmentation and generalized hypomelanosis. We speculate that KITLG biallelic loss-of-function variants cause generalized hypomelanosis, whilst variants with residual function lead to a variable auditory-pigmentary disorder mostly reminiscent of Waardenburg syndrome type 2 or piebaldism. CONCLUSIONS: We provide consolidating evidence that biallelic KITLG variants cause a distinct auditory-pigmentary disorder. We evidence a significant clinical variability, similar to the one previously observed in KIT-related piebaldism.