Genetic Variations Related to Angiotensin II Production and Risk for Basal Cell Carcinoma.

Basal cell carcinoma (BCC) is the most prevalent human neoplasm, with constantly increasing annual incidence. Despite its slow growth, BCC is locally invasive and, if left untreated, can cause severe complications, including metastasis and death. The renin-angiotensin system (RAS) plays a key role in electrolyte balance, atrial pressure, tissue development, homeostasis, and inflammation, but also in cancer development. After binding to its type 1 receptor (AT1R), angiotensin II (ANGII), the system's principal hormonal effector, regulates cancer pathways spanning from the formation of the initial cancer cell to the construction and nutrition of the tumor microenvironment, angiogenesis, proliferation, and metastasis. Although the role of RAS in the development of skin pathologies has not been widely researched, RAS-targeting antihypertensive medications have been shown to have a chemoprotective effect against BCC. Based on those findings, our group conducted a series of genetic association studies to investigate the association between common functional variations in key genes related to ANGII production (AGT, ACE, ACE2, AT1R, AT2R, and CMA1) and the risk of BCC occurrence. This review provides a summary of the current understanding of the ANGII involvement in BCC development. The reliable and easily assessed pool of genetic biomarkers may be used for predictive testing and prevention purposes in high-risk individuals.

Identification of Stage-Specific microRNAs that Govern the Early Stages of Sequential Oral Oncogenesis by Strategically Bridging Human Genetics with Epigenetics and Utilizing an Animal Model.

Oral squamous cell carcinoma (OSCC) is a highly prevalent and aggressive malignancy, with mortality rates reaching 60%, mainly due to its excessive diagnostic delay. MiRNAs, a class of crucial epigenetic gene-expression regulators, have emerged as potential diagnostic biomarkers, with >200 molecules exhibiting expressional dysregulation in OSCC. We had previously established an in silico methodology for the identification of the most disease-specific molecules by bridging genetics and epigenetics. Here, we identified the stage-specific miRNAs that govern the asymptomatic early stages of oral tumorigenesis by exploiting seed-matching and the reverse interplay between miRNA levels and their target genes' expression. Incorporating gene-expression data from our group's experimental hamster model of sequential oral oncogenesis, we bioinformatically detected the miRNAs that simultaneously target/regulate >75% of the genes that are characteristically upregulated or downregulated in the consecutive stages of hyperplasia, dysplasia, and early invasion, while exhibiting the opposite expressional dysregulation in OSCC-derived tissue and/or saliva specimens. We found that all stages share the downregulation of miR-34a-5p, miR124-3p, and miR-125b-5p, while miR-1-3p is under-expressed in dysplasia and early invasion. The malignant early-invasion stage is distinguished by the downregulation of miR-147a and the overexpression of miR-155-5p, miR-423-3p, and miR-34a-5p. The identification of stage-specific miRNAs may facilitate their utilization as biomarkers for presymptomatic OSCC diagnosis.

Stress-Related Roles of Exosomes and Exosomal miRNAs in Common Neuropsychiatric Disorders.

Exosomes, natural nanovesicles that contain a cargo of biologically active molecules such as lipids, proteins, and nucleic acids, are released from cells to the extracellular environment. They then act as autocrine, paracrine, or endocrine mediators of communication between cells by delivering their cargo into recipient cells and causing downstream effects. Exosomes are greatly enriched in miRNAs, which are small non-coding RNAs that act both as cytoplasmic post-transcriptional repression agents, modulating the translation of mRNAs into proteins, as well as nuclear transcriptional gene activators. Neuronal exosomal miRNAs have important physiologic functions in the central nervous system (CNS), including cell-to-cell communication, synaptic plasticity, and neurogenesis, as well as modulating stress and inflammatory responses. Stress-induced changes in exosomal functions include effects on neurogenesis and neuroinflammation, which can lead to the appearance of various neuropsychiatric disorders such as schizophrenia, major depression, bipolar disorder, and Alzheimer's and Huntington's diseases. The current knowledge regarding the roles of exosomes in the pathophysiology of common mental disorders is discussed in this review.

Clinical and Molecular Genetic Analysis of Cases with Ectodermal Dysplasia.

INTRODUCTION: Ectodermal dysplasias are a group of >200 clinically and congenitally heterogeneous disorders characterized by abnormal development in the ectodermal structures, such as hair, nails, teeth, and sweat glands. We report here the clinical and molecular genetic analysis of five Greek families with different types of ectodermal dysplasia (ED). SUBJECTS: The study involved 15 individuals from 5 Greek families that included 8 ED patients, 5 carriers of recessive X-linked or autosomal ED, and 2 healthy relatives. After genetic counseling, the parents signed an informed consent form before subsequent genetic testing. METHODS: Genomic DNA was isolated from white blood cells of all studied individuals. The search for mutations was realized in patients' DNA samples using next-generation sequencing (NGS) gene panel, whole exome sequencing (WES), chromosomal microarray analysis (CMA), and multiplex ligation-dependent probe amplification (MLPA) technique. RESULTS: The clinical diagnosis of common X-linked recessive hypohidrotic ectodermal dysplasia (HED) was suspected in five male patients with partial anodontia of baby and permanent teeth, hypohidrosis, and thin hair from three families. All HED patients were hemizygous for deletions in the EDA1 gene (Xq13.1): three related patients had a 20 bp deletion, one had a 19 bp deletion, and one had a 180 bp deletion. A female patient had the rare autosomal dominant syndrome of ankyloblepharon-ectodermal dysplasia-cleft lip/palate (AEC) caused by heterozygous missense mutation in the TP63 gene (3q28) that appeared de novo. Two siblings with hypotrichosis and hypodontia, a female and a male, had two pathogenic mutations in compound heterozygosity in the TSPEAR gene (21q22.3); therefore they presented with ectodermal dysplasia type 14 (ECTD14). CONCLUSION: Clinical and molecular genetic analysis may set an accurate diagnosis of different types of ED. In the reported families, genetic diagnosis and genetic counselling assisted the parents to view their children's condition realistically and to cooperate with the specialists who will contribute to the best possible treatment for their children.

The Impact of Genetic Variability of TGF-Beta Signaling Biomarkers in Major Craniofacial Syndromes.

Craniofacial development is a complex process involving several signaling pathways, including the one regulated by the TGF-beta (TGF-ß) superfamily of growth factors. Isoforms of TGF-ß play a vital part in embryonic development, notably in craniofacial patterning. Consequently, pathogenic variants in their coding genes may result in a variety of orofacial and craniofacial malformations. Here, we review the impact of genetic variability of TGF-ß signaling biomarkers in major disorders, including palatal and lip clefts, dental anomalies, and craniofacial syndromes, such as the Loeys-Dietz syndrome (LDS) and Camurati-Engelmann disease. Cleft lip and cleft palate are associated with missense mutations in the TGFB1 and TGFB3 genes, while mutations in the LTBP3 gene encoding TGF-ß binding protein 3 may cause selective tooth agenesis. Oligodontia may also be caused by TGFB1-inactivating mutations and/or by variations in the GREM2 gene, which disrupt the activity of gremlin 2, a TGF-ß/bone morphogenetic protein (BMP4) signaling antagonist. CED may be caused by mutations in the TGFB1 gene, while the TGF-ß-related genetic background of LDS consists mostly of TGFBR1 and TGFBR2 mutations, which may also impact the above syndromes' vascular manifestations. The potential utility of the TGF-ß signaling pathway factors as biomarkers that correlate genetics with clinical outcome of craniofacial malformations is discussed.

Angiotensinogen, Angiotensin-Converting Enzyme, and Chymase Gene Polymorphisms as Biomarkers for Basal Cell Carcinoma Susceptibility.

INTRODUCTION: The intake of angiotensin-converting enzyme (ACE) inhibitors and specific antagonists of angiotensin II receptors, widely used as antihypertensive drugs, significantly reduces the risk of developing basal cell carcinoma (BCC), highlighting the possible tumorigenic role of angiotensin II (AngII). We present here the investigated genetic association between the development of BCC and functional DNA polymorphisms M235T, I/D, and A1903G in the genes of angiotensinogen (AGT), angiotensin-converting enzyme (ACE), and chymase (CMA1), which mediate AngII production levels. METHODS: DNA samples of 203 unrelated Greeks were studied, including 100 patients with BCC and 103 matched healthy controls. RESULTS: The MT genotype of the AGT-M235T polymorphism was significantly more prevalent in the patient group (78.0%) versus the healthy control group (28.3%; p < 0.001). The DD genotype of the ACE-I/D polymorphism was also increased in BCC patients (72.8%) compared to controls (46.2%; p = 0.001). The heterozygous AG genotype of CMA1-A1903G was significantly more frequent in the BCC group (86%) than in the healthy controls (50.5%; p < 0.001). CONCLUSIONS: The MT, DD, and AG genotypes of the AGT- M235T, ACE-I/D, and CMA1-A1903G polymorphisms, respectively, were significantly increased in frequency within the group of cancer patients compared to the healthy controls. All three genotypes correspond to increased enzyme levels or activity and result in increased levels of AngII; therefore, they may be potentially utilized as reliable biomarkers associated with an individual's increased risk for BCC development.

The Role of MicroRNAs in Thrombosis.

MicroRNAs (miRNAs) are small noncoding regulatory RNA molecules that play a significant role in targeted downregulation of gene expression by RNA silencing and posttranscriptional regulation. Mounting evidence of recent studies indicates that there is dysregulation of expression level of a wide range of miRNAs in a variety of cardiovascular diseases related to thrombosis including venous thromboembolism, coronary artery disease, stroke, and myocardial infarction. In this review, the current knowledge on the role of miRNAs in thrombosis is discussed. Future research may further unravel the involvement of miRNAs in the pathogenesis of thrombosis as well as possibly clarify the clinical usefulness of miRNAs as biomarkers and potential therapeutic targets.

Prenatal Genetic Testing for X-Linked Hypohidrotic Ectodermal Dysplasia.

INTRODUCTION: Hypohidrotic ectodermal dysplasia (HED) is an X-linked recessive disorder, characterised by abnormally developed ectodermal tissues (sweat glands, enamel, hair, nails). HED is caused by mutations of the EDA1 gene (Xq13.1) which codes for ectodysplasin A, a transmembrane signalling protein, which plays a significant role in ectodermal differentiation. Here we present a case of prenatal testing for HED. METHODS: An 11-month-old boy with no family history was clinically diagnosed with HED. Genomic DNA was isolated from the patient's white blood cells, and the possible existence of mutations suspected for HED development was investigated by an NGS gene panel. Total DNA was also isolated from blood samples of his parents. After mutation detection and genetic counselling, a prenatal HED test was performed during the 12th week of the mother's next pregnancy. Embryonic DNA was isolated from a sample of chorionic villi. Parts of the EDA1, AMELX (X chromosome), and SRY (Y chromosome) genes were amplified by PCR, using the corresponding primers. RESULTS: The boy with HED was found to be a hemizygote for the c.595_613del (p. Pro199PhefsTer75) deletion in the EDA1 gene. The fetus was male (XY) that did not carry the pathological mutation. CONCLUSION: The initial diagnosis of a family member with HED in a case with no family history poses the question whether this type of ectodermal dysplasia is autosomal dominant (and the case is due to a de novo mutation), autosomal recessive, or X-linked recessive. Molecular detection of the responsible mutation allows proper genetic counselling, carrier testing, and prevention by prenatal testing.

Preimplantation Genetic Testing for Spastic Paraplegia Type 3.

INTRODUCTION: Spastic paraplegia type 3 (SPG3) is a common autosomal dominant neurogenetic disease, presenting during childhood with symptoms of mildly progressive spasticity and weakness of the lower limbs. SPG3 develops due to mutations of the ATL1 gene that encodes atlastin-1, a GTPase crucial for the function of dendrites of corticospinal neurons. Here we present a case of preimplantation genetic testing for SPG3. PATIENT AND METHODS: A 30-year-old woman with clinical symptoms of autosomal dominant spastic paraplegia since her first year of life asked for genetic counselling. DNA sequencing revealed the existence of mutation c.715C>T (p. R239C) in the ATL1 gene, confirming the diagnosis of SPG3. The patient asked for preimplantation testing for SPG3 after in vitro fertilization. An allele-specific method of PCR amplification was created in order to distinguish the mutant and the normal allele in the patient and her mother who also had SPG3, while her normal father served as control. The same nested PCR approach was used for the preimplantation testing of 11 available embryos. RESULTS: The presence of the c.715C>T (p. R239C) mutation in the ATL1 gene was found in five embryos while six embryos carried normal alleles and were selected for IVF implantation. After three failed gestation attempts and one pregnancy ended by a spontaneous miscarriage in the first trimester due to a chromosomal abnormality, there was an achieved pregnancy with a totally normal embryo. CONCLUSION: SPG3 may be degrading to a patient's quality of life; therefore, appropriate genetic counselling and preimplantation molecular testing may be provided as an option of prevention in offspring.

Craniofacial and Neurological Phenotype in a Case of Oculodentodigital Syndrome.

INTRODUCTION: Oculodentodigital syndrome (ODDS) is a rare genetic disorder caused by mutations in the gap junction GJA1 gene encoding connexin-43 (chromosome 6q22). A typical ODDS case is presented. MATERIAL AND METHODS: A 40-year-old male patient was examined neurologically and genetically. He had a history of recent parieto-occipital leukodystrophy, some episodes of temporary hearing loss, and characteristic facial features of ODDS. Sequencing of the GJA1 gene was performed in patient's total genomic DNA sample isolated from peripheral blood cells. RESULTS: A novel heterozygous missense mutation (443G>A) was identified in the GJA1 gene, resulting in coding for a different amino acid (Arg148Gln). CONCLUSION: The molecular genetic analysis confirmed the diagnosis of ODDS. The novel mutation, located within a calmodulin binding region of connexin-43, probably affects proper channel function.

Clinical and Molecular Study of Common Thrombophilia Mutation Prothrombin G20210A.

BACKGROUND: One of the most common genetic causes associated with thrombophilia is mutation G20210A of the coagulation factor II (F2) gene. MATERIALS AND METHODS: Data collected from 355 unrelated Greeks examined for the mutation G20210A over a period of two decades were anonymously analyzed. RESULTS: The statistical analysis confirmed the importance of F2 G20210A in thrombosis and the significance of a positive family history of thrombosis. An interesting finding was the increased prevalence of G20210A in men with thrombotic events aged >40 years. CONCLUSIONS: This study highlighted the great value of a positive family history of thrombosis and the importance of testing for this common mutation as a putative prevention strategy and a future biomarker for thrombophilia.

Phenotype and Genotype Study in a Case of Frontometaphyseal Dysplasia 1.

INTRODUCTION: Frontometaphyseal dysplasia 1 (FMD1) is a rare X-linked craniofacial syndrome belonging in the otopalatodigital spectrum of disorders. Here we present a case with severe FMD1 that was caused by a mutation in the FLNA gene located on Xq28. METHODS: A diagnosis for FMD1 was clinically set for a 22-year-old male who presented with cranial hyperostosis with marked supraorbital ridge, hypertelorism, progressive mixed hearing loss, partial anodontia, scoliosis, generalized skeletal dysplasia, and muscle atrophy. The patient's two older brothers had also severe FMD1 manifestations with generalized skeletal dysplasia, cranial hyperostosis, progressive hearing loss, and scoliosis, while their mother and maternal grandmother had some less prominent FMD1 signs. Total DNA was extracted from blood samples of the patient, his brothers, and his parents. RESULTS: DNA sequencing of all 48 exons of the FLNA gene revealed a single-point mutation (3476A>C) in exon 22. The missense mutation changes an Asp codon into an Ala codon in amino acid position 1159. The patient's two brothers had the same mutation, while their mother was a heterozygous carrier having both the mutant allele and the normal allele. CONCLUSION: The clinical diagnosis for FMD1 was confirmed by genetic analysis. It is evident that the FLNA gene product filamin A plays a critical developmental role in morphogenesis of several tissues being a cytoskeleton component, since mutations in its gene cause multiple manifestations and diverse disorders of the otopalatodigital spectrum.

Regulatory Role of MicroRNAs in Brain Development and Function.

MicroRNAs (miRNAs) are small non-coding RNA molecules of about 20-22 nucleotides. After their posttranscriptional maturation, miRNAs are loaded into the ribonucleoprotein complex RISC and modulate gene expression by binding to the 3' untranslated region of their target mRNAs through base-pairing, which in turn triggers mRNA degradation or translational inhibition. There is mounting evidence that miRNAs regulate various biological processes, including cell proliferation, differentiation, and apoptosis. Several studies have shown that miRNAs play an important role in neurogenesis and brain development.This review discusses recent progress on understanding the implication of precisely regulated miRNA expression in normal brain development and function. In addition, it reports known cases of dysregulation of miRNA expression and function implicated in the pathogenesis of neurodevelopmental disorders, craniofacial dysmorphic syndromes, neurodegenerative diseases, and psychiatric disorders. Current knowledge regarding the role of miRNAs in the brain in conjunction with the complex interplay between genetic and epigenetic factors are discussed.

Craniofacial and Neurological Phenotype in a Patient with De Novo 18q Microdeletion and 18p Microduplication.

INTRODUCTION: Chromosome 18q deletion syndrome (18q-) is a rare chromosomal disorder with phenotypic variability, including mental deficiency, short stature, hypotonia, cleft palate, and hearing impairment. We present a case with features of 18q- syndrome who had combined 18q partial monosomy and 18p partial trisomy. MATERIAL AND METHODS: A 50-year-old female patient was examined during the genetic counseling of her brother. She had a history of congenital cleft palate and developmental deficiency with hypotonia, hearing loss, and epilepsy until adulthood. Her family history was free of related cases. Karyotype analysis and comparative genomic hybridization array (aCGH) were performed in patient's blood samples. RESULTS: Clinical examination showed features of 18q- syndrome including hypotonia and tremor. Neuropsychological deficiency of moderate cognitive disorder was noticed. The patient's karyotype was normal. The aCGH analysis revealed 8 Mb deletion (del18q22.3q23) and 7.2 Mb duplication (dup18p11.32p11.23). CONCLUSION: Almost all patients' clinical features were associated with 18q- syndrome. There are very few reported cases with similar genotype possibly caused by a de novo unequal recombination mechanism.

Genetic Counseling for Adult-Onset Spinal and Bulbar Muscular Atrophy (Kennedy Syndrome): Multiple Cases of Prenatal Testing in a Family.

X-linked spinal and bulbar muscular atrophy (SBMA), also known as Kennedy syndrome, is an adult-onset neurodegenerative disorder characterized by slowly progressive muscle atrophy and other severe symptoms gradually leading to reduced mobility and ultimately to death due to respiratory failure. Two decades ago we reported the first prenatal diagnosis of SBMA worldwide. Here we present a Greek family in which we have performed seven prenatal DNA tests for SBMA mutation after extensive genetic counseling. Since there is not yet a cure for SBMA, prenatal testing may be a good choice for couples at risk for prevention of this neurodegenerative disorder in their offspring. The issues addressed during genetic counseling for such a disabling disorder of adult onset are discussed as a paradigm for other conditions with similar characteristics.

Recognition of Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) in Two Oligosymptomatic Sisters with Low CADASIL Scale Scores and a Venous Dysplasia: Report of a Novel Greek Family.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) due to mutations of the NOTCH3 gene is the most common cause of inherited cerebral small-vessel disease and one of the genetic causes of migraine with aura. The so-called CADASIL scale has been proposed as a clinical screening tool, and a score of 15 or higher seems useful in identifying patients with high probability of carrying NOTCH3 mutations. We studied a novel Greek family with clinical features compatible with CADASIL. Genetic analysis of NOTCH3 in the 2 living patients revealed the R182C mutation. Both patients had low scores (12 and 14) in the CADASIL scale, probably due to their relatively young age (38 and 37 years, respectively) at which cognitive decline and external capsule involvement have not developed yet. Another unusual feature in the second patient was a venous dysplasia in the parietal lobe. Observations presented here add to the notion that the CADASIL scale, although useful, probably needs a revision, taking into account the patient's age at which the score is calculated.

Cerebral Thrombosis: A Neurogenetic Approach.

Cerebral venous thrombosis (CVT) is a severe multifactorial condition with various clinical manifestations that may include headache, papilledema, seizures, focal deficits, coma and death. The mortality rate of untreated CVT is up to 50%, but it drops to 10% when CVT is properly treated. Prevention of CVT is feasible through healthy lifestyle, genetic counseling, molecular genetic analysis for common thrombophilia-related mutations, and prophylactic anticoagulative medication.

Huntington Disease: Genetics, Prevention, and Therapy Approaches.

Huntington's chorea or Huntington disease (HD) is a late-onset autosomal dominant neurodegenerative disorder caused by a trinucleotide repeat expansion. The multidisciplinary study of HD has been the focus of an international collaborating effort of basic and applied research for several decades. HD was the first human genetic disease mapped using linkage analysis of DNA polymorphisms and became a paradigm for scores of genes mapped in the same manner. Presymptomatic and prenatal testing have been available for HD families in the last 30 years, following genetic counseling and careful bioethical guidelines. Nevertheless, with the cure for the disease still elusive the uptake of predictive testing by at risk individuals is low. Current treatment of HD is mostly symptomatic, but ongoing observational studies, clinical trials and development of new gene silencing technologies have provided hopeful results.

Neurofibromatosis-Noonan Syndrome: A Possible Paradigm of the Combination of Genetic and Epigenetic Factors.

Neurofibromatosis-Noonan syndrome (NFNS) is a clinical entity possessing traits of autosomal dominant disorders neurofibromatosis type 1 (NF1) and Noonan syndrome (NS). Germline mutations that disrupt the RAS/MAPK pathway are involved in the pathogenesis of both NS and NF1. In light of a studied Greek family, a new theory for etiological pathogenesis of NFNS is suggested. The NFNS phenotype may be the final result of a combination of a genetic factor (a mutation in the NF1 gene) and an environmental factor with the epigenetic effects of muscle hypotonia (such as hydantoin in the reported Greek family), causing hypoplasia of the face and micrognathia.