Accuracy of Artificial Intelligence Models in the Prediction of Periodontitis: A Systematic Review

INTRODUCTION

Periodontitis is the main cause of tooth loss and is related to many systemic diseases. Artificial intelligence (AI) in periodontics has the potential to improve the accuracy of risk assessment and provide personalized treatment planning for patients with periodontitis. This systematic review aims to examine the actual evidence on the accuracy of various AI models in predicting periodontitis.

METHODS

Using a mix of MeSH keywords and free text words pooled by Boolean operators ('AND', 'OR'), a search strategy without a time frame setting was conducted on the following databases: Web of Science, ProQuest, PubMed, Scopus, and IEEE Explore. The QUADAS-2 risk of bias assessment was then performed.

RESULTS

From a total of 961 identified records screened, 8 articles were included for qualitative analysis: 4 studies showed an overall low risk of bias, 2 studies an unclear risk, and the remaining 2 studies a high risk. The most employed algorithms for periodontitis prediction were artificial neural networks, followed by support vector machines, decision trees, logistic regression, and random forest. The models showed good predictive performance for periodontitis according to different evaluation metrics, but the presented methods were heterogeneous.

CONCLUSIONS

AI algorithms may improve in the future the accuracy and reliability of periodontitis prediction. However, to date, most of the studies had a retrospective design and did not consider the most modern deep learning networks. Although the available evidence is limited by a lack of standardized data collection and protocols, the potential benefits of using AI in periodontics are significant and warrant further research and development in this area.

KNOWLEDGE TRANSFER STATEMENT

The use of AI in periodontics can lead to more accurate diagnosis and treatment planning, as well as improved patient education and engagement. Despite the current challenges and limitations of the available evidence, particularly the lack of standardized data collection and analysis protocols, the potential benefits of using AI in periodontics are significant and warrant further research and development in this area.

Motor imagery for paediatric neurorehabilitation: how much do we know? Perspectives from a systematic review

Background

Motor Imagery (MI) is a cognitive process consisting in mental simulation of body movements without executing physical actions: its clinical use has been investigated prevalently in adults with neurological disorders.

Objectives

Review of the best-available evidence on the use and efficacy of MI interventions for neurorehabilitation purposes in common and rare childhood neurological disorders.

Methods

systematic literature search conducted according to PRISMA by using the Scopus, PsycArticles, Cinahl, PUBMED, Web of Science (Clarivate), EMBASE, PsychINFO, and COCHRANE databases, with levels of evidence scored by OCEBM and PEDro Scales.

Results

Twenty-two original studies were retrieved and included for the analysis; MI was the unique or complementary rehabilitative treatment in 476 individuals (aged 5 to 18 years) with 10 different neurological conditions including, cerebral palsies, stroke, coordination disorders, intellectual disabilities, brain and/or spinal cord injuries, autism, pain syndromes, and hyperactivity. The sample size ranged from single case reports to cohorts and control groups. Treatment lasted 2 days to 6 months with 1 to 24 sessions. MI tasks were conventional, graded or ad-hoc. MI measurement tools included movement assessment batteries, mental chronometry tests, scales, and questionnaires, EEG, and EMG. Overall, the use of MI was stated as effective in 19/22, and uncertain in the remnant studies.

Conclusion

MI could be a reliable supportive/add-on (home-based) rehabilitative tool for pediatric neurorehabilitation; its clinical use, in children, is highly dependent on the complexity of MI mechanisms, which are related to the underlying neurodevelopmental disorder.

Klippel-Trenaunay Syndrome, Segmental/Focal Overgrowth Malformations: A Review

Klippel-Trenaunay syndrome is an uncommon, infrequent, congenital disorder characterized by a triad of capillary malformation, varicosities, and tissue and bone hypertrophy. The presence of two of these three signs is enough to obtain the diagnosis. Capillary malformations are usually present at birth, whereas venous varicosities and limb hypertrophy become more evident later. The syndrome has usually a benign course, but serious complications involving various organs, such as gastrointestinal and genitourinary organs, as well as the central nervous system, may be observed. Recently, Klippel-Trenaunay syndrome has been included in the group of PIK3CA-related overgrowth spectrum (PROS) disorders. In terms of this disorder, new results in etiopathogenesis and in modalities of treatment have been advanced. We report here a review of the recent genetic findings, the main clinical characteristics and related severe complications, differential diagnoses with a similar disorder, and the management of patients with this complex and uncommon syndrome.

Efficacy of videogames and exergames in pediatric neurorehabilitation: a systematic review

INTRODUCTION

In recent years, the rehabilitation of children with neurological disorders has taken into account the possibility of using videogaming consoles and virtual reality systems to make children's therapy more enjoyable, motivating, participated and effective. This study aims at conducting a systematic review about the use and the efficacy of digital games in pediatric neurorehabilitation.

EVIDENCE ACQUISITION

In accordance with the PRISMA approach, a rather wide-ranging search was conducted on PubMed, Scopus, and Web of Science databases by using different combinations of keywords based on MeSH terms.

EVIDENCE SYNTHESIS

Fifty-five papers have been included into this review, namely, 38 original studies and 17 reviews. The total number of children and adolescents is 573, with 58% of them being affected by cerebral palsy. Despite a wide variability in the adopted protocols, devices, assessment tools, and a more frequent focus on motor aspects than on cognitive ones, the results of the majority of the analyzed studies support the safety (i.e., absence of severe adverse effects) and efficacy of the videogame-based therapy.

CONCLUSIONS

Videogames, when administered by means of commercial consoles or ad-hoc digital systems, seem to be a valid support for physical therapy. Further researchers are needed to deeply investigate the role of this approach in cognitive therapy and cognitive outcomes.

Case report: A gain-of-function of hamartin may lead to a distinct "inverse TSC1-hamartin" phenotype characterized by reduced cell growth

Mutations of TSC1 and TSC2 genes cause classical Tuberous Sclerosis Complex (TSC), a neurocutaneous disorder characterized by a tendency to develop hamartias, hamartomas, and other tumors. We herein report on a girl, now aged 5 years, who presented a previously unreported, distinct clinical phenotype consisting of primary microcephaly (head circumference = 40 cm, -5.6 standard deviations), brain anomalies including hypoplasia of the corpus callosum (with a residual draft of the genu), simplified parieto-temporal gyral pattern, colpocephaly with ectasia of the temporal ventricular horns, intellectual disability, and a general pattern of reduced growth (with weight and height < 3rd centiles). No classical features of TSC were recorded; the girl harbored a novel missense variant in TSC1 (c.611G > A). We hypothesize that her clinical phenotype could be related to a "gain-of-function" of the TSC1 protein product hamartin, causing an increase in the effects of the protein on inhibition of its intracellular targets (i.e., mTORC or RAC1 pathways), resulting in a distinct "inverse TSC1-hamartin" phenotype characterized by reduced growth of cells instead of the more classical predisposition to increased cell growth.

Progressive Depletion of B and T Lymphocytes in Patients with Ataxia Telangiectasia: Results of the Italian Primary Immunodeficiency Network

Ataxia telangiectasia (AT) is a rare neurodegenerative genetic disorder due to bi-allelic mutations in the Ataxia Telangiectasia Mutated (ATM) gene. The aim of this paper is to better define the immunological profile over time, the clinical immune-related manifestations at diagnosis and during follow-up, and to attempt a genotype–phenotype correlation of an Italian cohort of AT patients. Retrospective data of 69 AT patients diagnosed between December 1984 and November 2019 were collected from the database of the Italian Primary Immunodeficiency Network. Patients were classified at diagnosis as lymphopenic (Group A) or non-lymphopenic (Group B). Fifty eight out of 69 AT patients (84%) were genetically characterized and distinguished according to the type of mutations in truncating/truncating (TT; 27 patients), non-truncating (NT)/T (28 patients), and NT/NT (5 patients). In 3 patients, only one mutation was detected. Data on age at onset and at diagnosis, cellular and humoral compartment at diagnosis and follow-up, infectious diseases, signs of immune dysregulation, cancer, and survival were analyzed and compared to the genotype. Lymphopenia at diagnosis was related per se to earlier age at onset. Progressive reduction of cellular compartment occurred during the follow-up with a gradual reduction of T and B cell number. Most patients of Group A carried bi-allelic truncating mutations, had a more severe B cell lymphopenia, and a reduced life expectancy. A trend to higher frequency of interstitial lung disease, immune dysregulation, and malignancy was noted in Group B patients. Lymphopenia at the onset and the T/T genotype are associated with a worst clinical course. Several mechanisms may underlie the premature and progressive immune decline in AT subjects.

Gaming Technology for Pediatric Neurorehabilitation: A Systematic Review

INTRODUCTION

The emergence of gaming technologies, such as videogames and virtual reality, provides a wide variety of possibilities in intensively and enjoyably performing rehabilitation for children with neurological disorders. Solid evidence-based results are however required to promote the use of different gaming technologies in pediatric neurorehabilitation, while simultaneously exploring new related directions concerning neuro-monitoring and rehabilitation in familiar settings.

AIM OF THE STUDY AND METHODS

In order to analyze the state of the art regarding the available gaming technologies for pediatric neurorehabilitation, Scopus and Pubmed Databases have been searched by following: PRISMA statements, PICOs classification, and PEDro scoring.

RESULTS

43 studies have been collected and classified as follows: 11 feasibility studies; six studies proposing home-system solutions; nine studies presenting gamified robotic devices; nine longitudinal intervention trials; and eight reviews. Most of them rely on feasibility or pilot trials characterized by small sample sizes and short durations; different methodologies, outcome assessments and terminologies are involved; the explored spectrum of neurological conditions turns out to be scanty, mainly including the most common and wider debilitating groups of conditions in pediatric neurology: cerebral palsy, brain injuries and autism.

CONCLUSION

Even though it highlights reduced possibilities of drawing evidence-based conclusions due to the above outlined biases, this systematic review raises awareness among pediatricians and other health professionals about gaming technologies. Such a review also points out a definite need of rigorous studies that clearly refer to the underlying neuroscientific principles.

Design and Validation of a Custom NGS Panel Targeting a Set of Lysosomal Storage Diseases Candidate for NBS Applications

Lysosomal storage diseases (LSDs) are a heterogeneous group of approximately 70 monogenic metabolic disorders whose diagnosis represents an arduous challenge for clinicians due to their variability in phenotype penetrance, clinical manifestations, and high allelic heterogeneity. In recent years, the approval of disease-specific therapies and the rapid emergence of novel rapid diagnostic methods has opened, for a set of selected LSDs, the possibility for inclusion in extensive national newborn screening (NBS) programs. Herein, we evaluated the clinical utility and diagnostic validity of a targeted next-generation sequencing (tNGS) panel (called NBS_LSDs), designed ad hoc to scan the coding regions of six genes (GBA, GAA, SMPD1, IDUA1, GLA, GALC) relevant for a group of LSDs candidate for inclusion in national NBS programs (MPSI, Pompe, Fabry, Krabbe, Niemann Pick A-B and Gaucher diseases). A standard group of 15 samples with previously known genetic mutations was used to test and validate the entire flowchart. Analytical accuracy, sensitivity, and specificity, as well as turnaround time and costs, were assessed. Results showed that the Ion AmpliSeq and Ion Chef System-based high-throughput NBS_LSDs tNGS panel is a fast, accurate, and cost-effective process. The introduction of this technology into routine NBS procedures as a second-tier test along with primary biochemical assays will allow facilitating the identification and management of selected LSDs and reducing diagnostic delay.

Treatment of lumbar and intrathoracic meningocele: bioethical implications

Myelomeningocele is  a  congenital malformation caused by a developmental defect of the spinal cord structures. The exactcause is unknown, but different factors have been involved includingradiation, malnutrition, drugs. Myelomeningocele can develop at any point in the spine, but the lumbosacral region is affected in over 75% of cases. Chest X-raysand computed tomography study are mandatory to reveal tracheal malformations or associatedanomaliesof the ribs.  Treatment of myelomeningocele must be multidisciplinary  and involve at the same time neurologists, radiologists, neurosurgeons, thoracic surgeons, bioethical experts and take care of the childand also of the family. Some experiences concern the possibility of a in-utero correction of myelomeningocele, in order to avoiding serious and progressive damages to the nervoussystem.  Given the improvement of myelomeningocele management, the quality of life is nowadays more acceptable than in the past; however, some severe forms of myelomeningocele cannot still be corrected: in this cases, a "non-interventional" approach may require a form of passive euthanasia that should be discussed and approved with and by parents and  Any dissent of the parents must be respected and considered reasonable. The choice of a "non-intervention", which should be guaranteed to all the people capable of self-determination, is not however so immediate and direct in the case of the minor: the dissent expressed on his behalf by the parents or legal representative may be ethically difficult to be accepted.In this case, the best interest of the child must prevail as the goal of any therapeutic choice.

SCN8A and Its Related Epileptic Phenotypes

Sodium channelopathies are among the most common single-gene causes of epilepsy and have been considered model disorders for the study of genetic epilepsies. Epilepsies due to SCN8A pathogenic variants can present with a broad range of phenotypes varying from a severe epileptic encephalopathy with multiple types of drug-resistant seizure to neurodevelopmental delay, mental retardation, and electroencephalogram (EEG) findings of multifocal spike and waves (mostly in the temporal/parietal/occipital areas). In rare cases, benign familial infantile seizures and developmental delay with/without ataxia have been reported. A first-level, specific SCN8A Sanger's sequencing, although available, is rarely performed because the clinical phenotype is not strictly characteristic and several overlaps with other genetic epilepsies may occur. Given its indistinctive phenotype, diagnosis is usually performed through a specific gene panel for epileptic encephalopathies, early epilepsies, or genetic epilepsy in general, or through whole exome sequencing (WES) and more rarely through whole genome sequencing (WGS). Mutations in SCN8A occur as an autosomal dominant trait. The great majority of individuals diagnosed with SCN8A epilepsy do not have an affected parent, because usually SCN8A patients do not reproduce, and mutations are inherited as a “de novo” trait. In rare cases, SCN8A mutations may be inherited in the setting of parental germline mosaicism. SCN8A-related epilepsies have not shown a clear genotype–phenotype correlation, the same variants have been described with different clinical expressivity and this could be due to other genetic factors or to interacting environmental factors. There is no standardized treatment for SCN8A-related epilepsy because of the rarity of the disease and the unavailability of specific, targeted drugs. Treatment is based mainly on antiepileptic drugs which include classic wide-spectrum drugs such as valproic acid, levetiracetam, and lamotrigine. Sodium-channel blockers (phenytoin, carbamazepine, oxcarbazepine, and lamotrigine) have shown appreciable results in terms of seizure reduction, in particular, in patients presenting gain-of-function mutations. Nowadays, new potentially transformative gene therapy treatment approaches are currently being explored, allowing in the next future, a precision-based treatment directed against the gene defect and protein alterations.

GRIN2A and GRIN2B and Their Related Phenotypes

Glutamate is the most relevant excitatory neurotransmitter of the central nervous system; it binds with several receptors, including N-methyl-D-aspartate receptors (NMDARs), a subtype of ionotropic glutamate receptor that displays voltage-dependent block by Mg2+ and a high permeability to Ca2+. GRIN2A and GRIN2B genes encode the GluN2A and GluN2B subunits of the NMDARs, which play important roles in synaptogenesis, synaptic transmission, and synaptic plasticity, as well as contributing to neuronal loss and dysfunction in several neurological disorders. Recently, individuals with a range of childhood-onset drug-resistant epilepsies, such as Landau–Kleffner or Lennox–Gastaut syndrome, intellectual disability (ID), and other neurodevelopmental abnormalities have been found to carry mutations in GRIN2A and GRIN2B, with high variable expressivity in phenotype. The first one is found mainly in epilepsy-aphasia syndromes, while the second one mainly in autism, schizophrenia, and ID, such as autism spectrum disorders. Brain magnetic resonance imaging alterations are found in some patients, even if without a clear clinical correlation. At the same time, increasing data on genotype–phenotype correlation have been found, but this is still not fully demonstrated. There are no specific therapies for the treatment of correlated NMDARs epilepsy, although some evidence with memantine, an antagonist of glutamate receptor, is reported in the literature in selected cases with mutation determining a gain of function.

TSC1 and TSC2: Tuberous Sclerosis Complex and Its Related Epilepsy Phenotype

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by a multisystemic involvement. In TSC, reduced function of TSC1 and TSC2 genes products (hamartin and tuberin, respectively) leads to an hyperactivation of the mechanistic target of rapamycin (mTOR) pathway and to a consequent cell growth dysregulation. In TSC patients, neurological and neuropsychiatric manifestations, especially epilepsy and neuropsychiatric comorbidities such as autism or intellectual disability, represent the most disabling features. In particular, epilepsy occurrs up to 80% of patients, is often drug resistant and is frequently associated with neurological impairment. Due to the burden of this morbidity, different treatment strategies have been proposed with the purpose to make patients epilepsy free, such as the use of different antiepileptic drugs like vigabatrin, carbamazepine, valproic acid, and levetiracetam. More recently, a mTOR inhibitor (i.e. everolimus) has showed promising results in terms of seizures reduction.

Neurocutaneous syndromes in art and antiquities

Neurocutaneous syndromes are a group of genetic disorders affecting the skin, the central and peripheral nervous system, and the eye with congenital abnormalities and/or tumors. Manifestations may also involve the heart, vessels, lungs, kidneys, endocrine glands and bones. When people with these disorders are portrayed in works of art, physicians have speculated on possible diagnoses. In particular, many figures have been labeled as possibly having a neurocutaneous disorder, sometimes distorting the popular conception of these diseases. We review numerous documents, drawings, prints, lithographs, xylographs, and portraits which span the ages from antiquity to the era of the pioneers behind the eponyms, depicting a large spectrum of neurocutaneous disorders.

Monogenic Epilepsies: Channelopathies, Synaptopathies, mTorpathies, and Otheropathies

Epilepsy has been historically defined as the recurrence of two or more seizures, together with typical electroencephalogram (EEG) changes, and significant comorbidities, including cardiac and autonomic changes, injuries, intellectual disability, permanent brain damage, and higher mortality risk. Epilepsy may be the consequence of several causes, including genetic anomalies, structural brain malformations, hypoxic–ischemic encephalopathy, brain tumors, drugs, and all contributing factors to the imbalance between excitatory and inhibitory neurons and modulatory interneurons which in turn provoke abnormal, simultaneous electric discharge(s) involving part, or all the brain. In the pregenetic, pregenomic era, in most cases, the exact cause of such neuronal/interneuronal disequilibrium remained unknown and the term “idiopathic epilepsy” was used to define all the epilepsies without cause. At the same time, some specific epileptic syndromes were indicated by the eponym of the first physician who originally described the condition (e.g., the West syndrome, Dravet syndrome, Ohtahara syndrome, and Lennox–Gastaut syndrome) or by some characteristic clinical features (e.g., nocturnal frontal lobe epilepsy, absence epilepsy, and epilepsy and mental retardation limited to females). In many of these occurrences, the distinct epileptic syndrome was defined mainly by its most relevant clinical feature (e.g., seizure semiology), associated comorbidities, and EEGs patterns. Since the identification of the first epilepsy-associated gene (i.e., CHRNA4 gene: cholinergic receptor neuronal nicotinic α polypeptide 4), one of the genes responsible for autosomal dominant nocturnal frontal lobe epilepsy (currently known as sleep-related hypermotor epilepsy) in 1995, the field of epilepsy and the history of epilepsy gene discoveries have gone through at least three different stages as follows: (1) an early stage of relentless gene discovery in monogenic familial epilepsy syndromes; (2) a relatively quiescent and disappointing period characterized by largely negative genome-wide association candidate gene studies; and (3) a genome-wide era in which large-scale molecular genetic studies have led to the identification of several novel epilepsy genes, especially in sporadic forms of epilepsy. As of 2021, more than 150 epilepsy-associated genes or loci are listed in the Online Mendelian Inheritance in Man database.

SCN1A and Its Related Epileptic Phenotypes

Epilepsy is one of the most common neurological disorders, with a lifetime incidence of 1 in 26. Approximately two-thirds of epilepsy has a substantial genetic component in its etiology. As a result, simultaneous screening for mutations in multiple genes and performing whole exome sequencing (WES) are becoming very frequent in the clinical evaluation of children with epilepsy. In this setting, mutations in voltage-gated sodium channel (SCN) α-subunit genes are the most commonly identified cause of epilepsy, with sodium channel genes (i.e., SCN1A, SCN2A, SCN8A) being the most frequently identified causative genes. SCN1A mutations result in a wide spectrum of epilepsy phenotypes ranging from simple febrile seizures to Dravet syndrome, a severe epileptic encephalopathy. In case of mutation of SCN1A, it is also possible to observe behavioral alterations, such as impulsivity, inattentiveness, and distractibility, which can be framed in an attention deficit hyperactivity disorder (ADHD) like phenotype. Despite more than 1,200 SCN1A mutations being reported, it is not possible to assess a clear phenotype–genotype correlations. Treatment remains a challenge and seizure control is often partial and transitory.

SCN1B Gene: A Close Relative to SCN1A

One of the first reported genes associated with epilepsy was SCN1B, which encodes for β-subunit of voltage-gated sodium channel of excitable cells and it is critical for neuronal function in both central and peripheral nervous system. β-subunits modulate the expression levels and functional properties of sodium channels and though their immunoglobulin domains may mediate interactions between channels and other proteins. Traditionally, SCN1B mutations were associated with generalized epilepsy with febrile seizures plus, a familial epilepsy syndrome characterized by heterogeneous phenotypes including febrile seizures (FS), febrile seizures plus (FS + ), mild generalized epilepsies, and severe epileptic encephalopathies. Throughout the years, SCN1B mutations have been also associated with Dravet syndrome and, more recently, with developmental and epileptic encephalopathies, expanding the spectrum associated with this gene mutations to more severe phenotypes.

SCN2A and Its Related Epileptic Phenotypes

Epilepsies due to SCN2A mutations can present with a broad range of phenotypes that are still not fully understood. Clinical characteristics of SNC2A-related epilepsy may vary from neonatal benign epilepsy to early-onset epileptic encephalopathy, including Ohtahara syndrome and West syndrome, and epileptic encephalopathies occurring at later ages (usually within the first 10 years of life). Some patient may present with intellectual disability and/or autism or movement disorders and without epilepsy. The heterogeneity of the phenotypes associated to such genetic mutations does not always allow the clinician to address his suspect on this gene. For this reason, diagnosis is usually made after a multiple gene panel examination through next generation sequencing (NGS) or after whole exome sequencing (WES) or whole genome sequencing (WGS). Subsequently, confirmation by Sanger sequencing can be obtained. Mutations in SCN2A are inherited as an autosomal dominant trait. Most individuals diagnosed with SCN2A–benign familial neonatal-infantile seizures (BFNIS) have an affected parent; however, hypothetically, a child may present SCN2A-BNFNIS as the result of a de novo pathogenic variant. Almost all individuals with SCN2A and severe epileptic encephalopathies have a de novo pathogenic variant. SNC2A-related epilepsies have not shown a clear genotype–phenotype correlation; in some cases, a same variant may lead to different presentations even within the same family and this could be due to other genetic factors or to environmental causes. There is no “standardized” treatment for SCN2A-related epilepsy, as it varies in relation to the clinical presentation and the phenotype of the patient, according to its own gene mutation. Treatment is based mainly on antiepileptic drugs, which include classic wide-spectrum drugs, such as valproic acid, levetiracetam, and lamotrigine. However, specific agents, which act directly modulating the sodium channels activity (phenytoin, carbamazepine, oxcarbamazepine, lamotrigine, and zonisamide), have shown positive result, as other sodium channel blockers (lidocaine and mexiletine) or even other drugs with different targets (phenobarbital).

Reconstructive Surgery in Children with Down Syndrome: Bioethical Implications

Down Syndrome is a genetic disorder caused by a third copy of chromosome 21. One of the main feature of the syndrome is the facial dysmorphism, characterized by broad, flat face, oblique eyelid rhymes, skin folds at the inner corner of the eyes (epicanthus), receding chin, protrusion of the tongue. These features are often social and functional obstacles, reducible with surgical interventions. The first facial plastic/cosmetic surgery approaches on Down children were performed in 1960 in Germany, Great Britain and the United States, where plastic surgeons began to reshape the Down patients physiognomy through the surgical correction of the face, tongue, eyes, nose, of the nostrils, of the neck. Recent studies have shown that in spite of the tendency to infections and early pulmonary hypertension in children with DS, surgery is not contraindicated, as previously suggested, but can be performed with very good results. This treatment has aesthetic, functional, rehabilitative, social effects, as well as favorable outcome on the familiar behavior. However different issues emerge in cases of patients presenting intellectual disability and unable to understand the consequences or the side effects related to plastic surgery. In this aspect, different Countries have enacted distinct laws directly regulating the consensuses for such intervention, with the goal to reduce the risks for the affected patients and the respect of their willing and social inclusion.

Neurocutaneous melanocytosis (melanosis)

Neurocutaneous melanosis (NCM; MIM # 249400; ORPHA: 2481], first reported by the Bohemian pathologist Rokitansky in 1861, and now more precisely defined as neurocutaneous melanocytosis, is a rare, congenital syndrome characterised by the association of (1) congenital melanocytic nevi (CMN) of the skin with overlying hypertrichosis, presenting as (a) large (LCMN) or giant and/or multiple (MCMN) melanocytic lesions (or both; sometimes associated with smaller "satellite" nevi) or (b) as proliferative melanocytic nodules; and (2) melanocytosis (with infiltration) of the brain parenchyma and/or leptomeninges. CMN of the skin and leptomeningeal/nervous system infiltration are usually benign, more rarely may progress to melanoma or non-malignant melanosis of the brain. Approximately 12% of individuals with LCMN will develop NCM: wide extension and/or dorsal axial distribution of LCMN increases the risk of NCM. The CMN are recognised at birth and are distributed over the skin according to 6 or more patterns (6B patterns) in line with the archetypical patterns of distribution of mosaic skin disorders. Neurological manifestations can appear acutely in infancy, or more frequently later in childhood or adult life, and include signs/symptoms of intracranial hypertension, seizures/epilepsy, cranial nerve palsies, motor/sensory deficits, cognitive/behavioural abnormalities, sleep cycle anomalies, and eventually neurological deterioration. NMC patients may be symptomatic or asymptomatic, with or without evidence of the typical nervous system changes at MRI. Associated brain and spinal cord malformations include the Dandy-Walker malformation (DWM) complex, hemimegalencephaly, cortical dysplasia, arachnoid cysts, Chiari I and II malformations, syringomyelia, meningoceles, occult spinal dysraphism, and CNS lipoma/lipomatosis. There is no systemic involvement, or only rarely. Pathogenically, single postzygotic mutations in the NRAS (neuroblastoma RAS viral oncogene homologue; MIM # 164790; at 1p13.2) proto-oncogene explain the occurrence of single/multiple CMNs and melanocytic and non-melanocytic nervous system lesions in NCM: these disrupt the RAS/ERK/mTOR/PI3K/akt pathways. Diagnostic/surveillance work-ups require physical examination, ophthalmoscopy, brain/spinal cord magnetic resonance imaging (MRI) and angiography (MRA), positron emission tomography (PET), and video-EEG and IQ testing. Treatment strategies include laser therapy, chemical peeling, dermabrasion, and surgical removal/grafting for CMNs and shunt surgery and surgical removal/chemo/radiotherapy for CNS lesions. Biologically targeted therapies tailored (a) BRAF/MEK in NCM mice (MEK162) and GCMN (trametinib); (b) PI3K/mTOR (omipalisib/GSK2126458) in NMC cells; (c) RAS/MEK (vemurafenib and trametinib) in LCMNs cells; or created experimental NMC cells (YP-MEL).

Improving diagnosis for rare diseases: the experience of the Italian undiagnosed Rare diseases network

Background

For a number of persons with rare diseases (RDs) a definite diagnosis remains undiscovered with relevant physical, psychological and social consequences. Undiagnosed RDs (URDs) require other than specialised clinical centres, outstanding molecular investigations, common protocols and dedicated actions at national and international levels; thus, many “Undiagnosed RDs programs” have been gradually developed on the grounds of a well-structured multidisciplinary approach.

Methods

The Italian Undiagnosed Rare Diseases Network (IURDN) was established in 2016 to improve the level of diagnosis of persons with URD living in Italy. Six Italian Centres of Expertise represented the network. The National Centre for Rare Diseases at the Istituto Superiore di Sanità coordinates the whole project. The software PhenoTips was used to collect the information of the clinical cases.

Results

One hundred and ten cases were analysed between March 2016 and June 2019. The age of onset of the diseases ranged from prenatal age to 51 years. Conditions were predominantly sporadic; almost all patients had multiple organs involvements. A total of 13/71 family cases were characterized by WES; in some families more than one individual was affected, so leading to 20/71 individuals investigated. Disease causing variants were identified in two cases and were associated to previously undescribed phenotypes. In 5 cases, new candidate genes were identified, although confirmatory tests are pending. In three families, investigations were not completed due to the scarce compliance of members and molecular investigations were temporary suspended. Finally, three cases (one familial) remain still unsolved. Twelve undiagnosed clinical cases were then selected to be shared at International level through PhenomeCentral in accordance to the UDNI statement.

Conclusions

Our results showed a molecular diagnostic yield of 53,8%; this value is comparable to the diagnostic rates reported in other international studies. Cases collected were also pooled with those collected by UDNI International Network. This represents a unique example of global initiative aimed at sharing and validating knowledge and experience in this field. IURDN is a multidisciplinary and useful initiative linking National and International efforts aimed at making timely and appropriate diagnoses in RD patients who still do not have a confirmed diagnosis even after a long time.

West syndrome: a comprehensive review

Since its first clinical description (on his son) by William James West (1793–1848) in 1841, and the definition of the classical triad of (1) infantile spasms; (2) hypsarrhythmia, and (3) developmental arrest or regression as “West syndrome”, new and relevant advances have been recorded in this uncommon disorder. New approaches include terminology of clinical spasms (e.g., infantile (IS) vs. epileptic spasms (ES)), variety of clinical and electroencephalographic (EEG) features (e.g., typical ictal phenomena without EEG abnormalities), burden of developmental delay, spectrum of associated genetic abnormalities, pathogenesis, treatment options, and related outcome and prognosis. Aside the classical manifestations, IS or ES may present with atypical electroclinical phenotypes (e.g., subtle spasms; modified hypsarrhythmia) and may have their onset outside infancy. An increasing number of genes, proteins, and signaling pathways play crucial roles in the pathogenesis. This condition is currently regarded as a spectrum of disorders: the so-called infantile spasm syndrome (ISs), in association with other causal factors, including structural, infectious, metabolic, syndromic, and immunologic events, all acting on a genetic predisposing background. Hormonal therapy and ketogenic diet are widely used also in combination with (classical and recent) pharmacological drugs. Biologically targeted and gene therapies are increasingly studied. The present narrative review searched in seven electronic databases (primary MeSH terms/keywords included West syndrome, infantile spasms and infantile spasms syndrome and were coupled to 25 secondary clinical, EEG, therapeutic, outcomes, and associated conditions terms) including MEDLINE, Embase, Cochrane Central, Web of Sciences, Pubmed, Scopus, and OMIM to highlight the past knowledge and more recent advances.

Consensus of the Italian Primary Immunodeficiency Network on transition management from pediatric to adult care in patients affected with childhood-onset inborn errors of immunity

Medical advances have dramatically improved the long-term prognosis of children and adolescents with inborn errors of immunity (IEIs). Transfer of the medical care of individuals with pediatric IEIs to adult facilities is also a complex task because of the large number of distinct disorders, which requires involvement of patients and both pediatric and adult care providers. To date, there is no consensus on the optimal pathway of the transitional care process and no specific data are available in the literature regarding patients with IEIs. We aimed to develop a consensus statement on the transition process to adult health care services for patients with IEIs. Physicians from major Italian Primary Immunodeficiency Network centers formulated and answered questions after examining the currently published literature on the transition from childhood to adulthood. The authors voted on each recommendation. The most frequent IEIs sharing common main clinical problems requiring full attention during the transitional phase were categorized into different groups of clinically related disorders. For each group of clinically related disorders, physicians from major Italian Primary Immunodeficiency Network institutions focused on selected clinical issues representing the clinical hallmark during early adulthood.

Highlights on Genomics Applications for Lysosomal Storage Diseases

Lysosomal storage diseases (LSDs) are a heterogeneous group of rare multisystem genetic disorders occurring mostly in infancy and childhood, characterized by a gradual accumulation of non-degraded substrates inside the lysosome. Although the cellular pathogenesis of LSDs is complex and still not fully understood, the approval of disease-specific therapies and the rapid emergence of novel diagnostic methods led to the implementation of extensive national newborn screening (NBS) programs in several countries. In the near future, this will help the development of standardized workflows aimed to more timely diagnose these conditions. Hereby, we report an overview of LSD diagnostic process and treatment strategies, provide an update on the worldwide NBS programs, and discuss the opportunities and challenges arising from genomics applications in screening, diagnosis, and research.

Aicardi–Goutières Syndrome Type 2: A Report on Two Cases with Different Phenotypes Caused by RNASEH2B Gene Mutations

Aicardi–Goutières syndrome (AGS) is a rare disorder characterized by acquired microcephaly, cerebral calcifications, leukodystrophy, cerebral atrophy, chronic lymphocytosis, and increased interferon-α in cerebrospinal fluid. We report on two children affected by AGS type 2, caused by mutations in RNASEH2B. The first child had the mutation c.529G > A (p.A177T) and presented with an atypical and mild phenotype, with delayed psychomotor development, calcifications of the brain white matter and basal ganglia, and interferon signature positivity. The disease course was stable. The second child presented the mutation c.554T > G (p.V185G) and showed a later onset (15 months) and a more progressive clinical course with functional inability in the upper limbs, steppage gait, and irritability. Despite immunoglobulin therapy, she developed to progressive tetraparesis and severe hypotonia. This case report highlights that RNASEH2B mutation cannot fully predict the phenotype of AGS type 2 when a mutation c.529G > A occurs. Moreover, an earlier symptomatology may be not related to a more severe prognosis or to a partial or absent response to treatment.

Primary Microcephaly with Novel Variant of MCPH1 Gene in Twins: Both Manifesting in Childhood at the Same Time with Hashimoto's Thyroiditis

This study is a clinical report on twin females affected by primary microcephaly who displayed at molecular analysis of heterozygous novel MCPH1 variant. The twins at the age of 10 years developed, in coincidental time, a diagnosis of autoimmune juvenile thyroiditis. The main clinical features presented by the twins consisted of primary microcephaly with occipitofrontal circumference measuring -2 or -3 standard deviation, facial dysmorphism, typical nonsyndromic microcephaly, and mild intellectual disability. Molecular analysis of the major genes involved in primary microcephaly was performed and the following result was found in the twins: MCPH1 ; chr8.6357416; c.2180 C > T (rs 199861426), p.Pro727. Leu; heterozygous; missense; variant of uncertain significance (class 3). At the age of 10 years, the twins started to have, in coincidental time, marked asthenia and episodes of emotiveness, and laboratory exams disclosed a high level of antithyroid peroxidase leading to the diagnosis of autoimmune juvenile thyroiditis with normal thyroid function. The novel heterozygous MCPH1 variant found in the twins may be directly or indirectly involved in the onset of the primary microcephaly. The thyroid disorder in the twins and its onset, in a coincidental time, confirmed the effect of genetic predisposition on the pathogenesis of the immune thyroiditis.

Chromosome 15q BP3 to BP5 deletion is a likely locus for speech delay and language impairment: Report on a four-member family and an unrelated boy

Background

Deletions in chromosome 15q13 have been reported both in healthy people and individuals with a wide range of behavioral and neuropsychiatric disturbances. Six main breakpoint (BP) subregions (BP1‐BP6) are mapped to the 15q13 region and three further embedded BP regions (BP3‐BP5). The deletion at BP4‐BP5 is the rearrangement most frequently observed compared to other known deletions in BP3‐BP5 and BP3‐BP4 regions. Deletions of each of these three regions have previously been implicated in a variable range of clinical phenotypes, including minor dysmorphism, developmental delay/intellectual disability, epilepsy, autism spectrum disorders, behavioral disturbances, and speech disorders. Of note, no overt clinical difference among each group of BP region deletions has been recorded so far.

Methods

We report on a four‐member family plus an additional unrelated boy affected by a BP3‐BP5 deletion that presented with typical clinical signs including speech delay and language impairment. A review of the clinical features associated with the three main groups of BP regions (BP4‐BP5, BP3‐BP5, and BP3‐BP4) deletions is reported.

Results

Array‐CGH analysis revealed in the mother (case 1) and in her three children (cases 2, 3, and 4), as well as in the unrelated boy (case 5), the following rearrangement: arr (hg19) 15q13.1‐q13.3 (29.213.402–32.510.863) x1.

Conclusion

This report, along with other recent observations, suggests the hypothesis that the BP region comprised between BP3 and BP5 in chromosome 15q13 is involved in several brain human dysfunctions, including impairment of the language development and, its deletion, may be directly or indirectly responsible for the speech delay and language deficit in the affected individuals.

Subjective status comparisons and depressive symptoms among migrants and refugees to Germany

Background

Prior research has identified perceptions of relative social status to affect mental health. We investigated whether migrants to Germany who perceive that they would have a higher relative social status if they were still in their country of origin experience more depressive symptoms than those who perceive no such status discrepancy.

Methods

Cross-sectional data were derived from a random sample of residents in the Berlin-Brandenburg region with a Croatian, Polish, Romanian, Syrian and/or Turkish citizenship (n = 728). Participants’ perception of their relative social status in Germany was measured using the MacArthur Scale of subjective social status (SSS). An adapted version of this scale was used to assess respondents’ hypothetical SSS in their country of origin if they had not migrated. Depressive symptoms were measured with the eight-item depression scale of the Patient Health Questionnaire. Diagonal reference models were used to examine whether discrepancies between the two status ratings were associated with depressive symptom severity.

Results

Most respondents reported a higher (35.6%) or similar (49.0%) hypothetical SSS in their country of origin compared to their SSS in Germany. Respondents whose SSS in Germany was lower than their hypothetical SSS in their country of origin experienced the most severe depressive symptoms. In the diagonal reference models, this association remained statistically significant (p &lt; 0.05), even after adjusting for objective socioeconomic position and other covariates. The pattern was similar for both refugees and non-refugees.

Conclusions

Our findings indicate that perceptions of having a lower social status in Germany than hypothetically in one’s country of origin are concomitant with poorer mental health among migrants. Prospective data are needed to address questions of causation and the direction of effects.

Key messages

Migrants who perceived that they would have a higher social status if they had not left their country of origin reported higher depressive symptoms than those with no such status discrepancy. This association persisted after adjusting for objective socioeconomic position in Germany.

Regulation of hepatokine gene expression in response to fasting and feeding: Influence of PPAR-α and insulin-dependent signalling in hepatocytes

AIM

In hepatocytes, the peroxisome proliferator-activated receptor (PPAR)-α and insulin receptor (IR) are critical for transcriptional responses to fasting and feeding, respectively. The present report analyzes the effects of nutritional status (fasting vs feeding) on the expression of a large panel of hepatokines in hepatocyte-specific PPAR-α (Pparα^hep-/-) and IR (IR^hep-/-) null mice.

METHODS

Pparα^hep-/- and IR^hep-/- mice, and their wild-type littermates, were subjected to fasting or feeding metabolic challenges, then analyzed for hepatokine gene expression. Experiments were conducted in mice of both genders.

RESULTS

Our data confirmed that PPAR-α is essential for regulating fasting-induced Fgf21 and Angptl4 expression. In mice lacking PPAR-α, fasting led to increased Igfbp1 and Gdf15 gene expression. In the absence of hepatic IR, feeding induced overexpression of Igfbp1, follistatin (Fst) and adropin (Enho), and reduced activin E (Inhbe) expression. Gender had only a modest influence on hepatokine gene expression in the liver.

CONCLUSION

The present results highlight the potential roles of hepatokines as a class of hormones that substantially influence nutritional regulation in both female and male mice.

Wyburn-Mason Syndrome

Wyburn–Mason syndrome is a very rare neurocutaneous disorder characterized by unilateral arteriovenous malformations of the midbrain associated with vascular abnormalities of eye and optic pathways, as well as multiple cutaneous nevi, reddish-bluish in color. The co-occurrence of such anomalies can be explained by an embryonic anomaly occurring in common ancestor cells, with the more severe cases related to development errors in the very early phases of gestation. Central nervous system and vision may be severely impaired: affected individuals may present with acute headache, hemiplegia, and homonymous hemianopsia in half of the cases. Seizures, cerebellar dysfunction, acute psychiatric signs, hallucinations, and temporal/spatial disorientation are reported more rarely. A progressive mental illness can become evident later in up to 30% of cases. Surgical removal is indicated only in superficially located arteriovenous malformations, while nonsurgical strategies (i.e., embolization and radiation therapy) are indicated for most of the lesions and represent the gold standard option in the treatment of this syndrome.

Nevus Sebaceous Syndrome

Nevus sebaceous (NS) is a hamartomatous disorder of the skin and adjacent tissues characterized by epidermal, follicular, sebaceous, and apocrine gland abnormalities. It occurs in approximately 1 in 1,000 live births. A hyperactivation of Ras pathways has been recently assumed to be the cause of this phenotype. NS lesions may be isolated or coupled with extracutaneous manifestations, mostly of the central nervous, ocular, and skeletal systems, or kidneys; in this case, the term “NS syndrome” is used. Cutaneous distribution of NS usually follows the linear patterns known as “lines of Blaschko,” with lines that do not follow the segmental trajectory of the peripheral sensory nerves but instead reflect the streams or trends of growth of embryonic tissues. Histological characteristics of the lesions appear to be actually more decisive than the clinical evaluation to distinguish between the types of epidermal nevus: the typical NS has both papillated epidermal hyperplasia and a predominance of subjacent abnormal follicular–sebaceous glands.

Seizures, mental retardation, and/or cognitive developmental delay are the most common neurologic abnormalities associated with NS and usually are present within the first months of life; eye and skeletal involvement may be present as well.

The definitive treatment of NS is full-thickness excision. However, the necessity and timing of excision to prevent possible future malignancy are not clear; lasers and photodynamic therapy are alternatives currently being explored for the treatment of NS, with varying degrees of success.

Hypomelanosis of Ito

Hypomelanosis of Ito (HI) is a congenital neurocutaneous syndrome presenting in the first year of life. It was first described by Ito in 1952 as a purely cutaneous disease presenting with skin hypopigmentation. Several extracutaneous manifestations were later described, and it is now known that several organs can be involved (including brain, muscle, bone, heart, eye, kidney, and teeth) and that the prognosis is strictly related to the number of involved organs. The incidence and prevalence of this syndrome have been estimated to range between 1 in 7,540 births and 1 in 82,000; the disorder affects both the sexes, occurs in all races, and is characterized by depigmentation of the skin along the lines of Blaschko on the trunk and extremities in whorled and linear streaks and patterns. The pathogenesis is unknown, but it is likely to be multifactorial. Several models of inheritance have been proposed but not proved; genetic mosaicism is nowadays the most likely explanation for its inheritance. The differential diagnosis comprises other disorders with hypopigmentation following the lines of Blaschko and thus includes the atrophic/hypopigmented (fourth) stage manifestations of incontinentia pigmenti of the Bloch–Sulzberger type, tuberous sclerosis complex, vitiligo, and skin fungal infections. Consensus recommendations for the screening of associated extracutaneous conditions do not exist and management is symptomatic, but a regular evaluation of somatic growth, neurodevelopment, endocrine status, eyes, and teeth should be performed, and the screening of renal function is also advisable. HI still represents a challenging disorder for the child neurologist and a controversial issue in the medical literature. Awareness of this disorder could allow an early diagnosis and appropriate genetic counseling and screening.

Mixed Vascular Nevus Syndrome

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 a purely cutaneous trait or as a hallmark of a neurocutaneous phenotype, the so-called mixed vascular nevus syndrome. The latter is characterized by the combination of paired vascular twin nevi and brain abnormalities of the Dyke–Davidoff–Masson type, consisting of crossed cerebral/cerebellar hemiatrophy with hypoplasia of the ipsilateral cerebral vessels, and homolateral hypertrophy of the skull and sinuses (hyperpneumatization) with contralateral hemispheric hypertrophy. In other cases, the paired vascular twin nevi and brain malformations of the Dyke–Davidoff–Masson type occur in association with systemic abnormalities consisting of facial asymmetry, skeletal anomalies, and disorders of autoimmunity. In 2014, Happle proposed to name the syndrome with the eponym Ruggieri–Leech's syndrome after the first two authors who reported (independently) this phenotype in different patients.

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 hyperpneumatization versus hypertrophy and brain megalencephaly/colpocephaly versus cortical dysplasia.

Blue Rubber Bleb Nevus Syndrome

Blue rubber bleb nevus syndrome (BRBNS) is a rare congenital disorder characterized by multifocal venous malformations mainly of the skin, soft tissue, and gastrointestinal tract. However, it may occur in any tissue including the nervous system. This syndrome most commonly occurs sporadically but can be associated with an autosomal dominant inheritance. Among the cases reported in the literature, the female/male ratio was ∼1:1. The diagnosis of BRBNS is based on the presence of characteristic cutaneous lesions with or without gastrointestinal bleeding and/or the involvement of other organs. Typical skin manifestations consist of soft, easily compressive, bluish papules similar to rubber-like nipples. Aside the skin, vascular lesions are usually found in the gastrointestinal tract, anywhere from the oral to the anal mucosa, but predominantly in the small bowel. Endoscopy provides the opportunity to treat and diagnose the lesions. BRBNS should be differentiated from hereditary hemorrhagic telangiectasia (Osler–Weber–Rendu syndrome), Klippel–Trenaunay syndrome, and Maffucci syndrome. The prognosis of BRBNS depends on which organs are involved and the extent of involvement. Most patients can live a long life with the disease, but the quality of life is limited due to gastrointestinal bleeding, oral drug therapy, and blood transfusions. Sudden massive gastrointestinal hemorrhage remains the most frequent cause of death. No curative therapy is currently available for this syndrome. The cutaneous lesions are usually asymptomatic and do not require treatment. The most important clinical problem is the management of acute or chronic bleeding from the multiple gastrointestinal venous malformations: a conservative approach should be instituted whenever the clinical features and the bleeding episodes are mild and only in a life-threatening situation surgery may be required. In the recent years, however, molecular targeted therapy with the mammalian target of rapamycin inhibitor sirolimus has been anecdotally employed with reduction in bleeding and shrinkage of vascular malformations.

Archetypical Patterns of Skin Manifestations in Neurocutaneous Disorders

The distribution of the cutaneous manifestations in neurocutaneous disorders is not casual; rather, it reflects predetermined patterns of skin arrangements, due to the action of the underlying genes, proteins, and/or metabolic pathways on the skin texture and appendages. These patterns of distribution are pathognomonic for each neurocutaneous disorder and can occur either in specific areas of the body (e.g., the forehead, the face, the trunk, the nails, one limb or one of more segments of the body) or following specific lines (e.g., lines of Blaschko) or taking peculiar shapes (e.g., leaf-like, ovoid, whorled, “S” or “V” shaped). These patterns of abnormal skin often mirror similar phenomena in extra-cutaneous organs/tissues, principally in the central nervous system but also in the eye, bone, heart/vessels, lung, kidney, and gut. A classification system, including several patterns of cutaneous arrangements (archetypical patterns) was proposed by the German dermatologist Rudolf Happle in 1993 and later expanded until 2014: this classification, originally meant to broadly explain (genetic and nongenetic) mosaic skin disorders and phenomena, was later expanded to explain the patterns of distribution of skin manifestations in some autosomal dominant skin disorders (genodermatoses). Currently, we recognize: (1) six archetypical patterns, including type 1 “along the lines of Blaschko” in (a) narrow or (b) large bands, type 2 “checkerboard” pattern, type 3 “phylloid” pattern, type 4 “patchy pattern without midline separation,” type 5 “lateralization” pattern, and type 6 “sash-like” pattern; (2) three less well-defined (so far unclassifiable) archetypical patterns, including (a) a diffuse hypopigmentation of the trunk versus smaller areas of normal skin on a unilateral aspect of the thorax and a segmental hyperpigmentation involving both arms and the trunk, (b) an “atypical” pattern along the Blaschko's lines, (c) the “mesotropic facial pattern,” and (iii) segmental manifestations of monogenic disorders, including (type 1) segmental areas of skin affected with the typical manifestations of a disease associated to otherwise unaffected skin and (type 2) segmental areas of skin affected with a very pronounced degree of the typical skin manifestations of a disease. In this article we review the existing literature on the early history of Blaschko's lines, the presentation of the (well-defined and unclassified) archetypical patterns and the segmental manifestations of monogenic disorders tailoring these concepts to neurocutaneous disorders.

Cutis Tricolor

Cutis tricolor is a skin abnormality consisting in a combination of congenital hyper- and hypopigmented skin lesions (in the form of paired macules, patches, or streaks) in close proximity to each other in a background of normal skin. It is currently regarded as a twin-spotting (mosaic) phenomenon. This phenomenon has been reported so far as a purely cutaneous trait, as a part of a complex malformation phenotype (Ruggieri–Happle syndrome), which includes distinct facial features, cataract, skull and vertebral defects, long bones dysplasia, corpus callosum, cerebellar and white matter anomalies, cavum vergae and holoprosencephaly, and other systemic abnormalities. Cutis tricolor has been also reported as a distinct type with multiple, disseminated smaller skin macules (cutis tricolor parvimaculata) or in association with other skin disturbances (e.g., phacomatosis achromico-melano-marmorata) or in the context of other neurocutaneous phenotypes (e.g., ataxia-telangiectasia and phacomatosis pigmentovascularis) or as a sign of complex malformation phenotypes (e.g., microcephaly and dwarfism). More than 20 studies reporting 40 cases are present in the literature with pure cutaneous or syndromic cutis tricolor phenomena and are analyzed in the present study, confirming and expanding the overall phenotype of cutis tricolor. In particular, (1) the skin abnormalities of the cutis tricolor do not evolve over time; (2) there is a typical facial phenotype with long, elongated face, thick and brushy eyebrows, hypertelorism, deep nasal bridge with large bulbous nose, and anteverted nostrils; (3) the skeletal defects are mild-to-moderate and do not progress or cause relevant orthopedic complications; (4) the neurological/behavioral phenotype does not progress and the paroxysmal events (if present) tend to decrease over time; (5) only three patients developed early onset (treatable) cataracts. Different pathologic hypotheses have been postulated, including, early or late postzygotic mutations involving the same gene loci (in the context of the so-called dydymotic theory): such mechanisms can explain the overall skin, bone, lens, and nervous system phenomena of migration of different streaks of clones in the different tissues.

Phacomatosis Pigmentokeratotica

In the group of the epidermal nevus syndromes, Happle defined in 1996 a separate entity characterized by the presence of an organoid epidermal nevus, sometimes showing sebaceous differentiation, and a speckled lentiginous nevus of the papular type, occasionally associated with extracutaneous anomalies including neurological, ophthalmological, and skeletal abnormalities. In particular, the syndrome is associated with mental retardation, epilepsy, deafness, hemiatrophy, dysesthesia, and hyperhidrosis, strabismus, lipodermoid of conjunctiva, coloboma and ptosis, and kyphosis, scoliosis, limb asymmetry, and hypertrophy. Rarely, hypertension, vascular abnormalities, atrioventricular block, hypophosphatemic rickets, and pheochromocytoma may occur. The organoid nevus follows the lines of Blaschko whereas the speckled lentiginous nevus is arranged in a checkerboard pattern. For this syndrome, the term “Phacomatosis Pigmentokeratotica” has been coined and, at the present, it is considered a very rare clinical entity, with less than 20 cases reported in the literature. Recent genetic findings have included this syndrome in the group of the mosaic RASopathies, after the discovery of mutations in the HRAS gene occurring in both sebaceous and vascular nevi, but not in nonaffected tissues.

Microcephaly-Capillary Malformation Syndrome

Microcephaly-capillary malformation is a relatively new syndrome, which has been reported since 2011 by three different research groups. It is an ultra-rare syndrome characterized by the co-occurrence of microcephaly and multiple capillary malformations in the skin, distal limb anomalies (ranging from nail dystrophy to total absence of one or more phalanxes and mostly localized in the foot), facial dysmorphisms, brain structural anomalies (reduced gyration, widened axial spaces, thin cortex, optic nerve atrophy), early-onset severe intractable epilepsy, and profound mental delay. Autosomal recessive mutations in STAMBP gene (2p13.1) have been reported as the only cause of the disorder, with a high penetrance. Currently, no definitive cure is available for the disorder, and treatment is mainly based on multiple antiepileptic drugs for the treatment of seizures, especially in the first years of life. Data on life-long concerns have not been reported, the older patient described so far being an 8-year-old boy.

Phacomatosis Pigmentovascularis

The coexistence of a widespread vascular nevus and an extensive pigmentary nevus is defined as “phacomatosis pigmentovascularis” (PPV). More than 250 (sporadic) cases of PPV have been so far reported, mainly in Asian or Asian-related populations: mutations in genes related to angiogenic pathways (RAS, MAPK, mTOR, PI3K/AKT, and GNAQ) have been recently identified as the causes of this complex phenotype. In many cases, mutations in two different genes may coexist, representing the classical example of “twin spotting” phenomenon. PPV is usually associated with several extracutaneous anomalies including ocular manifestations (melanosis bulbi, glaucoma, iris mammillations, megalocornea, buphthalmos, strabismus, and hyperpigmentation of the conjunctiva, sclera, episclera, iris, trabecular meshwork, and choroid) and musculoskeletal alterations (limb hypertrophy, Klippel–Trenaunay type abnormalities, hemifacial hypertrophy, hemicorporal hypertrophy, macrocephaly, microcephaly, and scoliosis). Central nervous system anomalies have been reported in most of the patients and include seizure, cognitive delay, cerebral atrophy, hydrocephalus, sensorineural deafness, and intracranial hypertension, as well as migraine, pseudotumor cerebri, and intracerebral vascular malformations. More rarely, PPV has been associated with structural and/or vascular renal anomalies, hepatosplenomegaly, pyogenic granuloma, cavernous hemangioma, portal hypertension, umbilical hernia, hypoplasia of leg veins, and hypo- or hyperactivity of the immune system.

Cerebellotrigeminal Dermal Dysplasia (Gómez-López-Hernández Syndrome)

Cerebellotrigeminal dermal (CTD) dysplasia is a rare neurocutaneous disorder characterized by a triad of symptoms: bilateral parieto-occipital alopecia, facial anesthesia in the trigeminal area, and rhombencephalosynapsis (RES), confirmed by cranial magnetic resonance imaging. CTD dysplasia is also known as Gómez-López-Hernández syndrome. So far, only 35 cases have been described with varying symptomatology. The etiology remains unknown. Either spontaneous dominant mutations or de novo chromosomal rearrangements have been proposed as possible explanations. In addition to its clinical triad of RES, parietal alopecia, and trigeminal anesthesia, CTD dysplasia is associated with a wide range of phenotypic and neurodevelopmental abnormalities.

Treatment is symptomatic and includes physical rehabilitation, special education, dental care, and ocular protection against self-induced corneal trauma that causes ulcers and, later, corneal opacification. The prognosis is correlated to the mental development, motor handicap, corneal–facial anesthesia, and visual problems. Follow-up on a large number of patients with CTD dysplasia has never been reported and experience is limited to few cases to date. High degree of suspicion in a child presenting with characteristic alopecia and RES has a great importance in diagnosis of this syndrome.

Encephalocraniocutaneous Lipomatosis (Haberland Syndrome or Fishman Syndrome)

Encephalocraniocutaneous lipomatosis is a sporadic, congenital neurocutaneous disorder characterized by the involvement of skin, central nervous system, and eye. A non-hereditary, autosomal mutation that may survive only in a mosaic state may be the cause of the clinical picture of the syndrome. Less than 80 patients have been so far reported and their clinical manifestations consisted of unilateral lipomatous hamartoma of the scalp or eyelid, epibulbar choristomas, and ipsilateral brain malformations. There is no clinical correlation between the severity of brain malformations and the clinical manifestations, and many patients with extremely extensive cerebral abnormalities are only minimal symptomatic. Seizures and mental retardation may also occur. The natural history is often favorable, without drug-resistant seizures and normal intelligence in most of the cases.

Becker's Nevus Syndrome

The simultaneous occurrence of a patch of light or dark brown hyperpigmentation with hypertrichosis (Becker's nevus) together with (usually ipsilateral) soft tissues hypoplasia (especially breast, in women) and underlying skeletal anomalies (i.e., vertebral hypoplasia, scoliosis, pectus carinatum or excavatum) represents the Becker's nevus syndrome (BNS) phenotype. It was first described (as a single cutaneous lesion) by Becker in 1949 and then associated with the surrounding musculoskeletal disorders. The syndrome has also been reported as pigmentary hairy epidermal nevus syndrome. Less than 100 cases have been reported in the literature, with a slightly higher incidence in females and only few familiar cases: paradominant postzygotic mutations and/or an androgen-dependent hyperactivation have been reported as the causes of the diseases.

The extracutaneous lesions are congenital and nonprogressive, and the natural history of the Becker's nevus is the same as that of isolated nevi: in prepubertal boys, the pigmentation may be less intense and the hairiness may be absent or mild, as occurs in women, whereas in men, there is an increase of hairiness after puberty. The treatment is essentially cosmetic, and potential therapeutic options include electrolysis, waxing, makeup, or laser.