Loss of heterozygosity in human skin

Porokeratoses-A Comprehensive Review on the Genetics and Metabolomics, Imaging Methods and Management of Common Clinical Variants

Porokeratosis is a heterogeneous group of keratinising disorders characterised by the presence of particular microscopic structural changes, namely the presence of the cornoid lamella. This structure develops as a consequence of a defective isoprenoid pathway, critical for cholesterol synthesis. Commonly recognised variants include disseminated superficial actinic porokeratosis, disseminated superficial porokeratosis, porokeratosis of Mibelli, palmoplantar porokeratosis (including porokeratosis palmaris et plantaris disseminata and punctate porokeratosis), linear porokeratosis, verrucous porokeratosis (also known as genitogluteal porokeratosis), follicular porokeratosis and porokeratoma. Apart from the clinical presentation and epidemiology of each variant listed, this review aims at providing up-to-date information on the precise genetic background, introduces imaging methods facilitating the diagnosis (conventional and ultraviolet-induced fluorescence dermatoscopy, reflectance confocal microscopy and pathology), discusses their oncogenic potential and reviews the literature data on the efficacy of the treatment used, including the drugs directly targeting the isoprenoid-mevalonate pathway.

Superimposed type 2 segmental atopic dermatitis: a case series and review of the literature

Generalized acquired dermatoses can seldom manifest more prominently or exclusively along the lines of Blaschko. Six individuals with segmental atopic dermatitis (AD) have been reported to date. We present three additional cases of segmental cutaneous manifestations superimposed on generalized AD, and review the relevant literature.

CRISPR-Cas9 gene editing induced complex on-target outcomes in human cells

CRISPR-Cas9 is a powerful tool to edit the genome and holds great promise for gene therapy applications. Initial concerns of gene engineering focus on off-target effects. However, in addition to short indel mutations (often < 50 bp), an increasing number of studies have revealed complex on-target results after double-strand break repair by CRISPR-Cas9, such as large deletions, gene rearrangement, and loss of heterozygosity. These unintended mutations are potential safety concerns in clinical gene editing. Here, in this review, we summarize the significant findings of CRISPR-Cas9-induced on-target deleterious outcomes and discuss putative ways to achieve safe gene therapy.

Generalized type 2 segmental disseminated superficial actinic porokeratosis coexisted with multiple cutaneous squamous cell carcinomas: Analysis of two cases

Porokeratosis (PK) is defined as hyperpigmented macules or patches with a distinctive, ridge-like hyperkeratotic border which is histologically characterized by a cornoid lamella. Here, we report two cases of linear porokeratosis which converted to multiple cutaneous squamous cell carcinoma after long history progression. In addition, patient 2 was accompanied by secondary dermal amyloid deposits, which was rare reported.

A six-attribute classification of genetic mosaicism

Mosaicism denotes an individual who has at least two populations of cells with distinct genotypes that are derived from a single fertilized egg. Genetic variation among the cell lines can involve whole chromosomes, structural or copy-number variants, small or single-nucleotide variants, or epigenetic variants. The mutational events that underlie mosaic variants occur during mitotic cell divisions after fertilization and zygote formation. The initiating mutational event can occur in any types of cell at any time in development, leading to enormous variation in the distribution and phenotypic effect of mosaicism. A number of classification proposals have been put forward to classify genetic mosaicism into categories based on the location, pattern, and mechanisms of the disease. We here propose a new classification of genetic mosaicism that considers the affected tissue, the pattern and distribution of the mosaicism, the pathogenicity of the variant, the direction of the change (benign to pathogenic vs. pathogenic to benign), and the postzygotic mutational mechanism. The accurate and comprehensive categorization and subtyping of mosaicisms is important and has potential clinical utility to define the natural history of these disorders, tailor follow-up frequency and interventions, estimate recurrence risks, and guide therapeutic decisions.

Biomarkers: paving stones on the road towards the personalized precision medicine for oral squamous cell carcinoma

Traditional therapeutics have encountered a bottleneck caused by diagnosis delay and subjective and unreliable assessment. Biomarkers can overcome this bottleneck and guide us toward personalized precision medicine for oral squamous cell carcinoma. To achieve this, it is important to efficiently and accurately screen out specific biomarkers from among the huge number of molecules. Progress in omics-based high-throughput technology has laid a solid foundation for biomarker discovery. With credible and systemic biomarker models, more precise and personalized diagnosis and assessment would be achieved and patients would be more likely to be cured and have a higher quality of life. However, this is not straightforward owing to the complexity of molecules involved in tumorigenesis. In this context, there is a need to focus on tumor heterogeneity and homogeneity, which are discussed in detail. In this review, we aim to provide an understanding of biomarker discovery and application for precision medicine of oral squamous cell carcinoma, and have a strong belief that biomarker will pave the road toward future precision medicine.

Clinical and Therapeutic Aspects of Linear Psoriasis: A Study of 30 Cases

BACKGROUND

Psoriasis affects 2-4% of the population, with the most common clinical type being plaque psoriasis. The linear form of psoriasis is very rare. The literature on linear psoriasis (LP) consists of only case reports, and data are few.

OBJECTIVE

This study aimed to better understand LP in a large-scale study.

PATIENTS AND METHODS

We retrospectively retrieved the medical records from 14 French medical centers of patients newly diagnosed clinically with LP, with or without the support of histology, between 1 February and 31 July 2015. For each case, we assessed the clinical features, treatments and treatment efficacy.

RESULTS

In total, 30 cases of LP (mean age 26.8 years, 13 males) were reported. Mean age at onset of LP was 20.0 years, with 18 developing LP in childhood. Ten patients had a family history of psoriasis, and two had psoriatic arthritis. A total of 19 cases were linear at onset, with concomitant classical psoriasis; these were termed "superimposed" LP. The remaining 11 cases were not associated with classical psoriasis and were termed "isolated" LP. In four of the superimposed cases, LP developed when the patient was receiving systemic treatment: methotrexate (n = 2), etanercept (n = 1) or infliximab (n = 1). Topical steroids were effective in 76% of cases in which they were used, and systemic treatment was effective in < 66%. Treatments were less effective in LP than in classical psoriasis.

DISCUSSION

We identified a wide range of LP, with two profiles: isolated LP and superimposed LP. Topical treatment usually evoked clinical response, with relative resistance to systemic therapy. Methotrexate and anti-tumor necrosis factor (TNF)-α therapies can possibly unmask LP.

Assessing genotoxicity of diuron on Drosophila melanogaster by the wing-spot test and the wing imaginal disk comet assay

The aim of this study was to evaluate the genotoxicity of the herbicide diuron in the wing-spot test and a novel wing imaginal disk comet assay in Drosophila melanogaster. The wing-spot test was performed with standard (ST) and high-bioactivation (HB) crosses after providing chronic 48 h treatment to third instar larvae. A positive dose-response effect was observed in both crosses, but statistically reduced spot frequencies were registered for the HB cross compared with the ST. This latter finding suggests that metabolism differences play an important role in the genotoxic effect of diuron. To verify diuron's ability to produce DNA damage, a wing imaginal disk comet assay was performed after providing 24 h diuron treatment to ST and HB third instar larvae. DNA damage induced by the herbicide had a significantly positive dose-response effect even at very low concentrations in both strains. However, as noted for the wing-spot test, a significant difference between strains was not observed that could be related to the duration of exposure between both assays. A positive correlation between the comet assay and the wing-spot test was found with regard to diuron genotoxicity.

Mixed vascular nevus syndrome: a report of four new cases and a literature review

BACKGROUND

Mixed vascular nevus (or nevus vascularis mixtus) represents an admixture of cutaneous vascular malformations of the telangiectatic type and angiospastic spots of nevus anemicus. It can occur as an purely cutaneous trait or as a hallmark of a neurocutaneous phenotype (mixed vascular nevus syndrome) characterised by the combination of: (I) paired vascular (telangiectatic and anemic) twin nevi and brain abnormalities of the Dyke-Davidoff-Masson type (i.e., crossed cerebral/cerebellar hemiatrophy with hypoplasia of the ipsilateral cerebral vessels and homolateral hypertrophy of the skull and sinuses (hyperpneumatisation) with contralateral hemispheric hypertrophy); or (II) paired vascular twin nevi and brain malformations of the Dyke-Davidoff-Masson type in association with systemic abnormalities consisting in facial asymmetry, skeletal anomalies (i.e., Legg-Calvé-Perthes-like disease) and disorders of autoimmunity (i.e., diabetes, thyroiditis). In 2014, Happle proposed to name the syndrome with the eponym Ruggieri-Leech syndrome.

METHODS

Review of the existing literature on nevus vascularis mixtus and information on our personal experience on new cases and follow-up of previously reported cases by some of us.

RESULTS

The existing literature revealed 4 previous studies including 33 cases with an inferred purely cutaneous trait and 3 cases with a combination of paired vascular twin nevi and brain malformation of the Dyke-Davidoff-Masson type. Our personal experience includes 4 unpublished patients (1 female and 3 males; currently aged 2 to 34 years) seen and followed-up at our Institutions in Italy who had: paired vascular nevi involving either the face (n=2) or the face and parts of the body (n=2); facial asymmetry (n=4); mild to moderate facial dysmorphic features (n=2); developmental delay (n=3); seizures/stroke-like episodes and associated hemiplegia (n=4); muscular hypotrophy (n=2); mild to moderate hemispheric atrophy (n=4); skull osseous hypertrophy (n=4); hyperpneumatisation of the sinuses (n=2); hypoplastic brain vessels (n=4); colpocephaly and malformation of cortical development (n=2). Follow-up data on our previous 2 cases revealed that the vascular abnormalities in the skin and nervous system were stable over years without neurological progression or deterioration.

CONCLUSIONS

Pathogenically, this complex phenotype suggests that embryonic pairing and somatic recombination of recessive (didymotic) alleles controlling the balance between constriction (i.e., nevus anemicus) and dilatation (i.e., nevus telangiectaticus) of blood vessels could be the primary event causing the phenomena of cutaneous and brain vascular twin spotting and the paired phenomena of skull hyperpneumatisation vs. hypertrophy and brain megalencephaly/colpocephaly vs. cortical dysplasia. This association is likely more frequent than previously thought and should be investigated by means of: (I) brain and spinal cord imaging (combination of CT and MRI studies); (II) skeletal X-ray studies (when dictated by clinical findings); (III) systemic ultrasound studies; (IV) neurophysiologic studies (EEG); (V) psychomotor testing; (VI) and laboratory investigation (including immune-mediated dysfunction).

Mosaic Neurocutaneous Disorders and Their Causes

Neurocutaneous disorders are a heterogeneous group of conditions (mainly) affecting the skin [with pigmentary/vascular abnormalities and/or cutaneous tumours] and the central and peripheral nervous system [with congenital abnormalities and/or tumours]. In a number of such disorders, the skin abnormalities can assume a mosaic patterning (usually arranged in archetypical patterns). Alternating segments of affected and unaffected skin or segmentally arranged patterns of abnormal skin often mirror similar phenomena occurring in extra-cutaneous organs/tissues [eg, eye, bone, heart/vessels, lung, kidney and gut]. In some neurocutaneous syndromes the abnormal mosaic patterning involve mainly the skin and the nervous system configuring a (true) mosaic neurocutaneous disorder; or an ordinary trait of a neurocutaneous disorder is sometimes superimposed by a pronounced linear or otherwise segmental involvement; or, lastly, a neurocutaneous disorder can occur solely in a mosaic pattern. Recently, the molecular genetic and cellular bases of an increasing number of neurocutaneous disorders have been unravelled, shedding light on the interplays between common intra- and extra-neuronal signalling pathways encompassing receptor-protein and protein-to-protein cascades (eg, RAS, MAPK, mTOR, PI3K/AKT and GNAQ pathways), which are often responsible of the mosaic distribution of cutaneous and extra-cutaneous features. In this article we will focus on the well known, and less defined mosaic neurocutaneous phenotypes and their related molecular/genetic bases, including the mosaic neurofibromatoses and their related forms (ie, spinal neurofibromatosis and schwannomatosis); Legius syndrome; segmental arrangements in tuberous sclerosis; Sturge-Weber and Klippel-Trenaunay syndromes; microcephaly/megalencephaly-capillary malformation; blue rubber bleb nevus syndrome; Wyburn-Mason syndrome; mixed vascular nevus syndrome; PHACE syndrome; Incontinentia pigmenti; pigmentary mosaicism of the Ito type; neurocutaneous melanosis; cutis tricolor; speckled lentiginous syndrome; epidermal nevus syndromes; Becker's nevus syndrome; phacomatosis pigmentovascularis and pigmentokeratotica; Proteus syndrome; and encephalocraniocutaneous lipomatosis.

The categories of cutaneous mosaicism: A proposed classification

Mosaic disorders can most easily be studied in the skin. This article presents a comprehensive overview of the different forms of cutaneous mosaicism. Major categories are genomic versus epigenetic mosaicism and nonsegmental versus segmental mosaicism. The class of nonsegmental mosaics includes single point mosaicism as exemplified by solitary benign or malignant skin tumors; disseminated mosaicism as noted in autosomal dominant tumor syndromes such as neurofibromatosis 1; and patchy mosaicism without midline separation as found in giant melanocytic nevus. The class of segmental mosaics includes segmental manifestation of lethal genes surviving by mosaicism as noted in Proteus syndrome; type 1 segmental mosaicism of autosomal dominant skin disorders reflecting heterozygosity for a postzygotic new mutation; type 2 segmental mosaicism of autosomal dominant skin disorders reflecting loss of heterozygosity that occurred at an early developmental stage in a heterozygous embryo; and isolated or superimposed segmental mosaicism of common polygenic skin disorders such as psoriasis or atopic dermatitis. A particular form of genomic mosaicism is didymosis (twin spotting). Revertant mosaicism is recognizable as one or more areas of healthy skin in patients with epidermolysis bullosa or other serious genodermatoses. The category of epigenetic mosaicism includes several X-linked, male lethal disorders such as incontinentia pigmenti, and the patterns of lyonization as noted in X-linked non-lethal disorders such as hypohidrotic ectodermal dysplasia of the Christ-Siemens-Touraine type. An interesting field of future research will be the concept of epigenetic autosomal mosaicism that may explain some unusual cases of autosomal transmission of linear hypo- or hypermelanosis.

Phakomatosis Pigmentovascularis Associated With Sturge-Weber Syndrome, Ota Nevus, and Congenital Glaucoma

Phakomatosis pigmentovascularis (PPV) is a rare congenital malformation syndrome that is characterized by a combination of capillary abnormalities and dermal melanocytosis.We describe 3 cases of PPV combined with bilateral Sturge-Weber syndrome (SWS), Ota nevus, and congenital glaucoma.Case 1 was a 2-year-old boy. Facial port-wine stains distributed along the 3 branches of his trigeminal nerves, which suggested the existence of SWS. Gray-blue patches were spread over the frontal and temporal areas of bilateral face, waist, buttocks, and thigh. Bilateral triangular alopecia was found on the temporal scalp. The diagnosis of Ota nevus was made by the bilateral scleral malanocystosis. Increased intraocular pressure, enlarged cornea, and pathologic optic disc cupping supported the diagnoses of infantile bilateral glaucoma. Case 2 was a 4-year-old boy. Port-wine stains were found on the face along the 3 branches of the trigeminal nerve and distributed along the trunk, arms, and legs. Mongolian spots spread over his frontal and temporal areas of the bilateral face, waist, buttocks, thigh, abdomen, and back. Infantile glaucoma was found in both eyes. Ota nevus were found in the both eyes. Optic coherent tomography (OCT) scans revealed increased thickness of choroid. Case 3 was a 5-year-old boy. Besides Ota nevus and infantile glaucoma in both eyes, color Doppler ultrasonography showed choroidal hemagioma. OCT scan showed increased choroidal thickness. The bilateral triangular alopecia on the child's temporal scalp was similar to that of Case 1. Cases 1 and 2 presented with port-wine stain patches that were consistent with the characteristic manifestation of PPV type IIb. However, the CMTC of Case 3 met the diagnostic criteria for PPV type Vb.Case 1 was treated with trabeculotomies in both eyes. For Cases 2 and 3, surgical interventions were not considered due to the high risks of antiglaucomatous operation complications. We prescribed them antiglaucoma indications.The simultaneously coexistence of PPV with SWS, Ota nevus, and congenital glaucoma is rare. In the clinic, additional detailed examinations and tests of PPV patients to exclude other ocular abnormalities or extraocular involvements are necessary.

Vascular malformation and common keratinocytic nevus of the soft type: phacomatosis pigmentovascularis revisited

Phacomatosis pigmentovascularis is a rare syndrome characterized by the coexistence of a pigmented nevus and a cutaneous vascular malformation. We report a 5-year-old boy with all the typical findings of phacomatosis pigmentovascularis type Ia. Although its existence according to the traditional classification has been questioned, this case represents a very rare association of a capillary vascular malformation and a common keratinocytic nevus of the soft type.

The genetics of human skin disease

The skin is composed of a variety of cell types expressing specific molecules and possessing different properties that facilitate the complex interactions and intercellular communication essential for maintaining the structural integrity of the skin. Importantly, a single mutation in one of these molecules can disrupt the entire organization and function of these essential networks, leading to cell separation, blistering, and other striking phenotypes observed in inherited skin diseases. Over the past several decades, the genetic basis of many monogenic skin diseases has been elucidated using classical genetic techniques. Importantly, the findings from these studies has shed light onto the many classes of molecules and essential genetic as well as molecular interactions that lend the skin its rigid, yet flexible properties. With the advent of the human genome project, next-generation sequencing techniques, as well as several other recently developed methods, tremendous progress has been made in dissecting the genetic architecture of complex, non-Mendelian skin diseases.

Phakomatosis Pigmentovascularis Type IIB: A Case Report

Phakomatosis Pigmentovasularis (PPV) is a rare condition defined by the presence of both vascular and melanocytic nevi occurring in the same patient. We report the case of a 27-year-old Chinese female who presented with generalized port-wine stains over the left trigeminal region, trunk, and limbs, diffuse dermal melanosis on the back, nevus of Ota on the right cheek, and scleral melanosis. Her port-wine stain on the trunk was distributed in a checker-board pattern. She was otherwise well. She was diagnosed with phakomatosis pigmentovascularis (PPV) Type IIb. The 'twin spotting' phenomenon has been proposed in the pathogenesis of PPV, and PPV is an example of non-alleleic twin spotting. The checkerboard distribution of port-wine stain in our patient follows the type II pattern of distribution in cutaneous mosaics. This lends further credence to the proposed hypothesis of twin spotting and cutaneous mosaicism in the pathogenesis of PPV.

Klippel-Trenaunay syndrome in a boy with concomitant ipsilateral overgrowth and undergrowth

Klippel-Trenaunay syndrome comprises congenital vascular malformations of the capillary (nevus flammeus), venous (varicosities) or lymphatic systems and disturbed (usually over-) growth of one or more extremities and adjacent parts of the trunk. In some individuals the affected body area may show reduced rather than increased growth. Such patients have been described inverse Klippel-Trenaunay syndrome and included within the spectrum of the syndrome. We report on a 3-year-old boy with vascular malformation of the nevus flammeus type extending from the right buttock to the sole of the right foot with clinical and radiological evidence of leg varicosities and underlying deficiency of the soft tissues and bone. In addition, he had macrodactyly of the first, second, and third toes with small nails, and cutaneous syndactyly of the second and third toes of the ipsilateral foot. Cranial magnetic resonance imaging showed high signal lesions in the peritrigonal areas with normal spinal images. This mosaic phenotype demonstrates that decreased and increased growth can coexist in the same body area of an individual with Klippel-Trenaunay syndrome.

Recombinogenic activity of Pantoprazole(®) in somatic cells of Drosophila melanogaster

Pantoprazole^® is one of the leading proton pump inhibitors (PPIs) used in the treatment of a variety of diseases related to the upper gastrointestinal tract. However, studies have shown an increased risk of developing gastric cancer, intestinal metaplasia and hyperplasia of endocrine cells with prolonged use. In the present study, the somatic mutation and recombination test (SMART) was employed to determine the mutagenic effects of Pantoprazole on Drosophila melanogaster. Repeated treatments with Pantoprazole were performed on 72-hour larvae of the standard (ST) and high bioactivation (HB) crosses at concentrations of 2.5, 5.0, and 10.0 μM. In addition, doxorubicin (DXR) was administered at 0.4 mM, as a positive control. When administered to ST descendants, total number of spots were statistically significant at 2.5 and 5.0 μM concentrations. For HB descendants, a significant increase in the total number of spots was observed among the marked transheterozygous (MH) flies. Through analysis of balancer heterozygous (BH) descendants, recombinogenic effects were observed at all concentrations in descendants of the HB cross. In view of these experimental conditions and results, it was concluded that Pantoprazole is associated with recombinogenic effects in Drosophila melanogaster.

Pairomics, the omics way to mate choice

The core aspects of the biology and evolution of sexual reproduction are reviewed with a focus on the diploid, sexually reproducing, outbreeding, polymorphic, unspecialized, altricial and cultural human species. Human mate choice and pair bonding are viewed as central to individuals' lives and to the evolution of the species, and genetic assistance in reproduction is viewed as a universal human right. Pairomics is defined as an emerging branch of the omics science devoted to the study of mate choice at the genomic level and its consequences for present and future generations. In pairomics, comprehensive genetic information of individual genomes is stored in a database. Computational tools are employed to analyze the mating schemes and rules that govern mating among the members of the database. Mating models and algorithms simulate the outcomes of mating any given genome with each of a number of genomes represented in the database. The analyses and simulations may help to understand mating schemes and their outcomes, and also contribute a new cue to the multicued schemes of mate choice. The scientific, medical, evolutionary, ethical, legal and social implications of pairomics are far reaching. The use of genetic information as a search tool in mate choice may influence our health, lifestyle, behavior and culture. As knowledge on genomics, population genetics and gene-environment interactions, as well as the size of genomic databases expand, so does the ability of pairomics to investigate and predict the consequences of mate choice for the present and future generations.

Phacomatosis pigmentokeratotica is a "pseudodidymosis"

In phacomatosis pigmentokeratotica, papular nevus spilus coexists with nevus sebaceus. The disorder was thought to be a didymosis with early postzygotic recombination. In this issue, however, Groesser and co-workers provide a new concept. Both nevi originate from a single heterozygous HRAS mutation in a pluripotent progenitor cell. This new understanding has implications for other proposed examples of didymosis in humans.

Laser therapy treatment of phacomatosis pigmentovascularis type II: two case reports

Introduction

Phacomatosis pigmentovascularis is a rare congenital condition characterized by vascular malformation associated with extensive pigmented nevi. Even though it forms a large, prominent skin lesion, therapy for phacomatosis pigmentovascularis is rarely discussed. To the best of our knowledge, this is the first report of phacomatosis pigmentovascularis type II treated with combined laser therapy using Q-switched alexandrite and long-pulsed dye lasers.

Case presentations

In the first of two cases reported here, a 2-week-old Japanese baby girl was given a diagnosis of phacomatosis pigmentovascularis type II and Klippel–Trénaunay syndrome because of port-wine stains, cutis marmorata telangiectatica congenita, and aberrant Mongolian spots over her trunk and limbs. After five laser therapy sessions under general anesthesia, her aberrant Mongolian spots and port-wine stains have improved. But interestingly, the cutis marmorata telangiectatica congenita on the patient's back has improved without laser therapy.

In the second case, a 4-month-old Japanese baby boy was referred to us because of port-wine stains, cutis marmorata telangiectatica congenita, and aberrant Mongolian spots over his face, trunk and limbs. Phacomatosis pigmentovascularis type II was diagnosed and laser therapy was started. After three laser therapy sessions under general anesthesia, the aberrant Mongolian spots and port-wine stains have improved. The cutis marmorata telangiectatica congenita on the baby's back, buttocks, and arms has faded somewhat without laser therapy.

Conclusions

Combined laser therapy improved the phacomatosis pigmentovascularis skin lesions, but was not effective for the cutis marmorata telangiectatica congenita with hemiatrophy. Cutis marmorata telangiectatica congenita without atrophy can be expected to improve on its own. Our results will assist physicians considering how best to treat patients with phacomatosis pigmentovascularis.

Genodermatoses caused by genetic mosaicism

Genetic mosaicism is defined as the existence of at least two genetically distinct cell populations within one individual. Mosaic presentation of genetic disorders is common and is often particularly obvious in the skin, because there it will generate recognizable patterns. Recognizing those can frequently assist in establishing a diagnosis. In this review, we discuss the mechanisms that give rise to genetic mosaicism. We describe its most frequent cutaneous manifestations that are relevant to paediatric practice. While most mosaic genetic diseases are rare, it is important to recognize them so that patients and parents may receive appropriate genetic counselling. Moreover, recent developments are now resulting in novel, targeted treatments for such disorders that promise to considerably improve patients' lives.

Nevus vascularis mixtus (cutaneous vascular twin nevi) associated with intracranial vascular malformation of the Dyke-Davidoff-Masson type in two patients

The term twin spotting refers to phenotypes characterized by the spatial and temporal co-occurrence of two (or more) different nevi arranged in variable cutaneous patterns, and can be associated with extra-cutaneous anomalies. Several examples of twin spotting have been described in humans including nevus vascularis mixtus, cutis tricolor, lesions of overgrowth, and deficient growth in Proteus and Elattoproteus syndromes, epidermolytic hyperkeratosis of Brocq, and the so-called phacomatoses pigmentovascularis and pigmentokeratotica. We report on a 28-year-old man and a 15-year-old girl, who presented with a previously unrecognized association of paired cutaneous vascular nevi of the telangiectaticus and anemicus types (naevus vascularis mixtus) distributed in a mosaic pattern on the face (in both patients) and over the entire body (in the man) and a complex brain malformation (in both patients) consisting of cerebral hemiatrophy, hypoplasia of the cerebral vessels and homolateral hypertrophy of the skull and sinuses (known as Dyke-Davidoff-Masson malformation). Both patients had facial asymmetry and the young man had facial dysmorphism, seizures with EEG anomalies, hemiplegia, insulin-dependent diabetes mellitus (IDDM), autoimmune thyroiditis, a large hepatic cavernous vascular malformation, and left Legg-Calvé-Perthes disease (LCPD) [LCPD-like presentation]. Array-CGH analysis and mutation analysis of the RASA1 gene were normal in both patients.

Choroid plexus papilloma in a girl with hypomelanosis of Ito

The authors report a case of choroid plexus papilloma in a girl with hypomelanosis of Ito, and they review the literature in brief. Hypomelanosis of Ito is a rare neurocutaneous syndrome characterized by cutaneous hypopigmented whorls, streaks, and patches along lines of Blaschko. Most patients exhibit CNS manifestations, including psychomotor retardation, seizures, hypotonia, and ataxia. A 6-year-old girl with hypomelanosis of Ito was referred to the authors' hospital with bilateral tumors in the lateral ventricles. The right lateral ventricle tumor was surgically removed. Immunohistochemical investigations revealed the tumor to be a choroid plexus papilloma (WHO Grade I). A chromosomal investigation revealed that the tumor tissue demonstrated a large loss of heterozygosity at chromosome 10. The case reported here serves as a reminder that de novo brain tumors may arise in patients with chromosomal mosaicism.

Patterned disorders in dermatology

The skin gives us an opportunity to study pathologies unapparent in other systems such as patterned disorders. Among the best-identified patterns of skin disorders are the well-known lines of Blaschko, but other types of skin-patterned lesions have also been recognized. This short review will describe and discuss these different patterns and their pathophysiologic mechanisms, such as somatic mosaicism and X-chromosome associated mosaicism. Cutaneous patterned disorders are thought to be associated usually with inherited diseases per se, but in fact they are also reported in so-called acquired diseases. These cases suggest the existence of an underlying defect in a gene closely associated with the disease pathogenesis. The study of these acquired patterned disorders in the future may help us to understand the biologic foundations and pathogenesis of common human diseases.

Monozygotic twin discordance for phacomatosis cesioflammea further supports the post-zygotic mutation hypothesis

Phacomatosis pigmentovascularis (PPV) is a group of sporadic skin disorders combining widespread cutaneous capillary malformations and pigmented nevi. Etiopathogenesis of the various forms of PPV is unknown, although a non-allelic twin spotting has been proposed as the most likely underlying mechanism. We report on the second instance of monozygotic twin discordance for PPV. Identical twins were observed shortly after birth, one affected by PPV and the other healthy, except for a standard Mongolian spot. Membrane examination was compatible with a monochorionic diamniotic pregnancy, and microsatellite analysis demonstrated monozygosity. This report confirms that PPV likely originates from a post-zygotic mutation rising shortly after conception and affecting different cell lineages. Speculations about mechanisms linked to phenotypic discrepancies among identical twins were also put forward.

Spectrum of skeletal abnormalities in a complex malformation syndrome with "cutis tricolor" (Ruggieri-Happle syndrome)

BACKGROUND

The term cutis tricolor describes the combination of congenital hyper- and hypopigmented skin lesions in close proximity to each other in a background of normal complexion. This phenomenon has been reported: (i) as a purely cutaneous trait; (ii) as a part of a complex malformation syndrome (Ruggieri-Happle syndrome - RHS); (iii) as a distinct type [cutis tricolor parvimaculata]; (iv) in association with other (e.g. vascular) skin disturbances.

OBJECTIVES

To delineate the spectrum of skeletal defects in cutis tricolor.

METHODS

Retrospective and prospective analysis of skeletal surveys in 14 subjects (eight men; six women; aged 2-28 years) with cutis tricolor [4 purely cutaneous trait; 10 syndromic (RHS)].

RESULTS

Bone abnormalities were recorded in 71.4% (10/14) of patients [100% (10/10) of cases with (other-than-skeletal) extra-cutaneous manifestations vs. null (0/4) in cases with purely cutaneous traits] and included overall small skull (n = 6); prognathism (n = 6); 'J'-shaped pituitary fossa (n = 1); absence of atlas posterior arch (n = 3); frontal bossing (n = 6); scoliosis (n = 9) with kyphosis (n = 6) and/or lordosis (n = 6); vertebral (n = 9) and ribs (n = 4) defects. Negative ZFHX1B gene analyses excluded overlaps with Mowat-Wilson syndrome.

CONCLUSIONS

Cutis tricolor may be a marker of underlying skeletal involvement particularly in subjects with a complex syndromic (RHS) phenotype.

Ichthyosis hystrix Curth-Macklin type in an African girl

Ichthyosis hystrix Curth-Macklin type is a rare autosomal dominant skin disorder characterized by extensive hyperkeratosis and palmo-plantar keratoderma. It results from heterozygous frameshift mutation in keratin 1 gene (KRT1). Histological features, showing perinuclear vacuolization and binucleated cells, are similar to those of epidermolytic hyperkeratosis except for the absence of epidermolysis. The present report describes the condition in a 16-year-old African girl where available treatment was disappointing.

Monozygotic twins discordant for phacomatosis pigmentovascularis: evidence for the concept of twin spotting

The term phacomatosis pigmentovascularis (PPV) refers to the occurrence of vascular nevi with melanocytic or epidermal nevi. We report on monozygotic twins (MZTs) discordant for phacomatosis cesioflammea (PPV type II) providing evidence for the mechanism of twin spotting in the development of PPV. The affected twin had a nevus flammeus on the right arm and the right maxilla, and a pigmented area on the trunk in keeping with a persistent, aberrant Mongolian spot. The affected twin had bilateral ocular melanocytosis with abnormal scleral pigmentation, iris mamillations, increased pigmentation of the trabecular meshwork, and increased fundal pigmentation and secondary glaucoma. DNA testing confirmed monozygosity. This case of MZTs discordant for PPV supports the hypothesis that PPV results from mosaicism due to a post-zygotic mutational event and the concept of twin spotting.

Mibelli revisited: a case of type 2 segmental porokeratosis from 1893

In autosomal dominant skin disorders, a pronounced mosaic involvement may sometimes be found to be superimposed on the ordinary nonsegmental lesions. Such "type 2 segmental manifestation" reflects loss of heterozygosity occurring at an early developmental stage, giving rise to a cell clone that lacks the corresponding wild-type allele. Here, this genetic concept is applied to an unusual case of plaque-type porokeratosis of Mibelli (PM) as published in 1893 by Vittorio Mibelli in the International Atlas of Rare Skin Diseases. The right forearm and hand of the 21-year-old patient showed a pronounced linear porokeratosis that had developed since the age of 2 years. Moreover, nonsegmental lesions of PM involved both hands and forearms as well as the face and the neck, having first been noticed at the age of 7 years. Two siblings and the father were likewise affected with PM. Hence, Mibelli's case from 1893 meets all of the criteria of a type 2 segmental manifestation of an autosomal dominant skin disorder. Recognizing such cases of superimposed segmental involvement may help elucidate the molecular basis of PM.

Familial clustering of giant congenital melanocytic nevi

Giant congenital melanocytic nevus (GCMN) is an infrequently occurring congenital malformation. GCMN generally occurs in isolation but rare familial occurrence points to a genetic background. We present two cases of familial GCMN: one with two affected siblings and another with two affected double second cousins. Familial occurrence of GCMN reported in literature is reviewed and an overview of the embryology and proliferation given, illustrating the plethora of factors that might lead to GCMN formation. The pattern of inheritance is likely not Mendelian and discordance in identical twins and the segmental distribution of lesions suggest a post-zygotic mutation. A polygenic paradominant inheritance best explains the clinically observed transmission pattern. Candidate genes include those influencing neural crest development and melanocyte proliferation.

Speckled lentiginous nevus syndrome associated with musculoskeletal abnormalities

Speckled lentiginous nevus syndrome is a recently described neurocutaneous disorder characterized by speckled lentiginous nevus in association with hyperhidrosis, skin dysesthesia, and muscular weakness in an ipsilateral manner. We report a 9-year-old boy with a large speckled lentiginous nevus on his trunk, bilateral upper extremities, and neck associated with hyperhidrosis and nonspecific pain in the distribution of the nevus in addition to prominent upper extremity asymmetry and scoliosis. Similar musculoskeletal abnormalities have been reported in patients with phacomatosis pigmentovascularis and phacomatosis pigmentokeratotica which feature speckled lentiginous nevus; however, this patient demonstrates striking musculoskeletal abnormalities in the absence of coexisting vascular lesions or nevus sebaceous.