[Translated article] Congenital and Hereditary Nail Disease.

Nail disorders in newborns can show independently or as components of systemic illnesses or genodermatoses. The examination of these abnormalities is complex and sometimes challenging. However, familiarity with these disorders can significantly contribute to uncovering potential underlying conditions. This review includes the physiological nail changes seen within the first few months of life, such as Beau's lines, onychoschizia, koilonychia, congenital nail fold hypertrophy of the first digit, and onychocryptosis. This review also focuses on the most relevant congenital disorders reported and how to perform differential diagnosis. Finally, this review highlights those hereditary diseases in which nail involvement is crucial for diagnosis, such as nail-patella syndrome, congenital pachyonychia, or congenital dyskeratosis, among others.

Congenital nail abnormalities.

Congenital nail disorders are an uncommon presenting symptom which can be difficult to diagnose and manage. Nail diseases in the pediatric population differ from those in adults in terms of diagnosis, approach and management. In most cases, they do not require treatment and resolve with growth. Physicians need to be able to recognize them, to reassure the parents. The most frequently encountered pathologies associated with nail disorder are syndactyly, acrosyndactyly, symbrachydactyly, macrodactyly, Wassel I thumb duplication, Kirner's deformity and congenital onychodysplasia of the index finger. Treatment usually consists in surgical correction of the deformity. Nail malformation can also be an aspect of a systemic disease. It may provide a clue for screening, and should not be overlooked. Nail conditions can be the first sign of nail-patella syndrome, ectodermal dysplasia, dyskeratosis congenita, epidermolysis bullosa, pachyonychia congenita or lung disease. Medical treatment is therefore discussed on a case-by-case basis.

PLACK syndrome is potentially treatable with intralipids.

We describe an 11-year-old girl with PLACK Syndrome (peeling skin, leukonychia, acral punctate keratosis, cheilitis, and knuckle pads), who was found to have a novel homozygous variant in CAST, the pathogenicity of which was confirmed using blood-derived RNA. There is no established treatment for PLACK syndrome. However, we demonstrate for the first time that this condition is associated with low levels of vitamin A and essential fatty acids, which prompted us to consider a potential treatment strategy. Indeed, we initiated this patient on intravenous lipid infusion (Vitalipid®; an emulsion of fat-soluble vitamins and lipofundin-MCT/LCT 20%) and the response was dramatic. Following the fourth monthly course of treatment, pruritis disappeared and the skin lesions showed remarkable objective improvement. PLACK syndrome is a very rare genodermatosis and only six families have been described to date with pathogenic CAST variants. This is the first report of an objective response to a therapeutic agent, which suggests that PLACK is a potentially treatable condition. The remarkable response we report and the relative safety of the intervention should prompt healthcare providers who care for PLACK syndrome patients to explore this as a potential treatment strategy in future studies.

Iso-Kikuchi Syndrome: Report of 3 Pediatric Cases. / Síndrome de Iso-Kikuchi: 3 casos en la edad pediátrica.

Iso-Kikuchi syndrome, or congenital onychodysplasia of the index finger, is an uncommon condition characterized by total anonychia or dysplasia of the nail of the index finger. It is occasionally accompanied by underlying bone abnormalities and is rarely associated with other conditions. Although various hypotheses have been put forward to explain the pathophysiology of the syndrome, its etiology remains unknown. We report the cases of 3 pediatric patients (2 boys and 1 girl) with nail changes and bone abnormalities consistent with Iso-Kikuchi syndrome. We highlight the importance of recognizing this entity early to avoid the need for additional tests and unnecessary treatment.

A novel pathogenic variant in the FZD6 gene causes recessive nail dysplasia in a large Iranian kindred.

BACKGROUND: Nail disorder nonsyndromic congenital (NDNC) is a very rare clinically and genetically heterogeneous disease inherited both in recessive or dominant modes. FZD6 is a component of Wnt-FZD signaling pathway in which recessive loss-of-function variants in the corresponding genes could lead to nail anomalies. OBJECTIVE: A large multiplex family with NDNC was referred for genetic counselling. Thorough genetic evaluation was performed. METHODS: PCR-Sanger sequencing was carried out for the coding exons and exon-intron boundaries of the FZD6 gene. Co-segregation analysis, in silico evaluation and computational protein modeling was accomplished. RESULTS: A homozygous 1bp deletion variant, c.1859delC (p.Ser620Cysfs*75), leading to a truncating protein was found in the patient. Parents were heterozygous for the variant. The variant was found to be co-segreagting with the phenotype in the family. Computational analysis and protein modeling revealed its pathogenic consequence by disturbing the cytoplasmic domain structure and signaling through loss of phosphorylation residues. The variant met the criteria of being pathogenic according to the ACMG guideline. CONCLUSIONS: This is the first report of the genetic diagnosis of NDNC in Iran. We also report a novel pathogenic variant. The study of the FZD6 gene is recommended as the first step in the diagnostic routing of the autosomal recessive NDNC patients with enlarged nails.

Isolated recessive nail dysplasia caused by FZD6 mutations: report of three families and review of the literature.

Congenital abnormalities of the nail are rare conditions that are most frequently associated with congenital ectodermal syndromes involving several of the epidermal appendages including the skin, teeth, hair and nails. Isolated recessive nail dysplasia (IRND) is much rarer but has recently been recognized as a condition resulting in 20-nail dystrophy in the absence of other cutaneous or extracutaneous findings. A few case reports have identified mutations in the Frizzled 6 (FZD6) gene in families presenting with abnormal nails consistent with IRND. These reports have highlighted the role of Wnt-FZD signalling in the process of nail formation. We report three families presenting with features of IRND, in whom we identified mutations in FZD6, including one previously unreported mutation.

Nail abnormalities in patients with vitiligo

Abstract: Background: Vitiligo is an acquired pigmentary skin disorder affecting 0.1-4% of the general population. The nails may be affected in patients with an autoimmune disease such as psoriasis, and in those with alopecia areata. It has been suggested that nail abnormalities should be apparent in vitiligo patients. Objective: We sought to document the frequency and clinical presentation of nail abnormalities in vitiligo patients compared to healthy volunteers. We also examined the correlations between nail abnormalities and various clinical parameters. Methods: This study included 100 vitiligo patients and 100 healthy subjects. Full medical histories were collected from the subjects, who underwent thorough general and nail examinations. All nail changes were noted. In the event of clinical suspicion of a fungal infection, additional mycological investigations were performed. Results: Nail abnormalities were more prevalent in the patients (78%) than in the controls (55%) (p=0.001). Longitudinal ridging was the most common finding (42%), followed by (in descending order): leukonychia, an absent lunula, onycholysis, nail bed pallor, onychomycosis, splinter hemorrhage and nail plate thinning. The frequency of longitudinal ridging was significantly higher in patients than in controls (p<0.001). Conclusions: Nail abnormalities were more prevalent in vitiligo patients than in controls. Systematic examination of the nails in such patients is useful because nail abnormalities are frequent. However, the causes of such abnormalities require further study. Longitudinal ridging and leukonychia were the most common abnormalities observed in this study.

Two novel POC1A mutations in the primordial dwarfism, SOFT syndrome: Clinical homogeneity but also unreported malformations.

Primordial dwarfism encompasses rare conditions characterized by severe intrauterine growth retardation and growth deficiency throughout life. Recently, three POC1A mutations have been reported in six families with the primordial dwarfism, SOFT syndrome (Short stature, Onychodysplasia, Facial dysmorphism, and hypoTrichosis). Using a custom-designed Next-generation sequencing skeletal dysplasia panel, we have identified two novel homozygous POC1A mutations in two individuals with primordial dwarfism. The severe growth retardation and the facial profiles are strikingly similar between our patients and those described previously. However, one of our patients was diagnosed with severe foramen magnum stenosis and subglottic tracheal stenosis, malformations not previously associated with this syndrome. Our findings confirm that POC1A mutations cause SOFT syndrome and that mutations in this gene should be considered in patients with severe pre- and postnatal short stature, symmetric shortening of long bones, triangular facies, sparse hair and short, thickened distal phalanges.

Genetics of human isolated hereditary nail disorders.

Human hereditary nail disorders constitute a rare and heterogeneous group of ectodermal dysplasias. They occur as isolated and/or syndromic ectodermal conditions where other ectodermal appendages are also involved, and can occur associated with skeletal dysplasia. 'Nail disorder, nonsyndromic congenital' (OMIM; Online Mendelian Inheritance in Man) is subclassified into 10 different types. The underlying genes identified thus far are expressed in the nail bed and play important roles in nail development and morphogenesis. Here, we review the current literature on nail disorders and present a coherent review on the genetics of nail disorders. This review will pave the way to identifying putative genes and pathways involved in nail development and morphogenesis.

Nail disorders in infants and children.

PURPOSE OF REVIEW: Nail diseases in infants and children are an uncommon cause of consultation and are often difficult to diagnose and to manage. This review will cover nail diseases that are most commonly seen in clinical practice, including congenital and hereditary disorders and inflammatory, infective, and neoplastic nail diseases. The purpose of the review is to help the reader to recognize nail disorders at an early age and to manage them appropriately. RECENT FINDINGS: Two recent large studies have reported the clinical findings of genetic disorders involving the nails, that is, pachyonychia congenita and epidermolysis bullosa. Only a few articles gave a comprehensive review of a disease, as occurred for onychomycosis, while the majority of the reports published in the recent literature involve single cases. SUMMARY: Nail diseases in children and neonates are not easy to diagnose by nonexperts. Basic knowledge of the anatomy and biology of the nail facilitates their diagnosis as the understanding of their pathophysiology. This review gives hints at the most common nail diseases that affect infants and children.

Pediatric nail conditions.

Pediatric nail findings are plentiful and can range from benign processes to the initial signs of a systemic condition. The examination of the nail is an essential part of the pediatric physical examination. The nail unit consists of the nail plate, the nail matrix, the hyponychium, the nail bed, and the surrounding nail folds. Conditions that affect the nail unit have a variety of etiologies; these include inflammatory, congenital, and hereditary conditions as well as tumors and trauma. This review describes many of the nail conditions that are seen in the pediatric population.

Congenital subungual melanocytic nevus with a pseudo-Hutchinson sign.

We describe a 29-year-old woman with congenital melanonychia striata and compound nevus of the right first digit. There was extension of the hyperpigmentation onto the proximal nail fold, even beyond the borders established by the band of melanonychia striata. A dermal plaque with irregular borders and variegated pigmentation was also present over the distal digit extending from the pigmented region of the hyponychium. A limited number of biopsy proven congenital subungual melanocytic nevi have been reported in the literature. Interestingly, we found that the majority of these cases present with longitudinal melanonychia in association with periungual hyperpigmentation, constituting a pseudo-Hutchinson sign. Currently studies evaluating the diagnostic test characteristics of Hutchinson sign are lacking. While Hutchinson sign is traditionally considered a worrisome feature it is certainly not pathognomonic and a malignant cause should not be assumed without thorough assessment.

Cutaneous manifestations in patients with POEMS syndrome.

BACKGROUND: Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome is a rare multisystem paraneoplastic condition associated with plasma cell dyscrasia. METHODS: From our institution's dysproteinemia database, 107 patients met criteria for polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome between January 1, 2000, and October 1, 2009. Medical records were reviewed for documented syndrome features at diagnosis. We assessed prevalence of skin findings and associations between dermatologic and other characteristic disease findings. RESULTS: Of the 107 patients, 96 (90%) had a recognized cutaneous manifestation. Hyperpigmentation and hemangioma were most common (47%), followed by hypertrichosis (38%). Vascular skin changes--acrocyanosis (34%), Raynaud phenomenon (20%), hyperemia/erythema (20%), flushing (16%), or rubor (11%)--occurred in 62%; white nails, sclerodermoid changes, and clubbing occurred in 30%, 26%, and 6%, respectively. Mean number of skin findings per patient was 2.9 (median, 3.0; range, 0-7). Presence of cutaneous manifestation was associated with abnormal pulmonary function tests (P < 0.001); immunoglobulin G gammopathy was associated with hyperpigmentation and hypertrichosis. No other significant associations were seen. CONCLUSIONS: The high prevalence of skin findings (90%) shows the value of dermatologic evaluation in diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome. Our data indicate new associations between skin findings and other disease characteristics.