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Genomic alterations are a driving force in the multistep process of head and neck cancer (HNC) and result from the interaction of exogenous environmental exposures and endogenous cellular processes. Each of these processes leaves a characteristic pattern of mutations on the tumor genome providing the unique opportunity to decipher specific signatures of mutational processes operative during HNC pathogenesis and to address their prognostic value. Computational analysis of whole exome sequencing data of the HIPO-HNC (Heidelberg Center for Personalized Oncology-head and neck cancer) (n = 83) and TCGA-HNSC (The Cancer Genome Atlas-Head and Neck Squamous Cell Carcinoma) (n = 506) cohorts revealed five common mutational signatures (Catalogue of Somatic Mutations in Cancer [COSMIC] Signatures 1, 2, 3, 13 and 16) and demonstrated their significant association with etiological risk factors (tobacco, alcohol and HPV16). Unsupervised hierarchical clustering identified four clusters (A, B, C1 and C2) of which Subcluster C2 was enriched for cases with a higher frequency of signature 16 mutations. Tumors of Subcluster C2 had significantly lower p16INK4A expression accompanied by homozygous CDKN2A deletion in almost one half of cases. Survival analysis revealed an unfavorable prognosis for patients with tumors characterized by a higher mutation burden attributed to signature 16 as well as cases in Subcluster C2. Finally, a LASSO-Cox regression model was applied to prioritize clinically relevant signatures and to establish a prognostic risk score for head and neck squamous cell carcinoma patients. In conclusion, our study provides a proof of concept that computational analysis of somatic mutational signatures is not only a powerful tool to decipher environmental and intrinsic processes in the pathogenesis of HNC, but could also pave the way to establish reliable prognostic patterns.

Abnormal pronuclear formation during fertilisation and subsequent early embryonic arrest results in female infertility. In recent years, with the prevalence of assisted reproductive technology, a few genes have been identified that are involved in female infertility caused by abnormalities in oocyte development, fertilisation and embryonic development. However, the genetic factors responsible for multiple pronuclei formation during fertilisation and early embryonic arrest remain largely unknown.We aim to identify genetic factors responsible for multiple pronuclei formation during fertilisation or early embryonic arrest.Whole-exome sequencing was performed in a cohort of 580 patients with abnormal fertilisation and early embryonic arrest. Effects of mutations were investigated in HEK293T cells by western blotting and immunoprecipitation, as well as minigene assay.We identified a novel homozygous missense mutation (c.397TG, p.C133G) and a novel homozygous donor splice-site mutation (c.546+5GA) in the meiotic geneOur study has identified mutations in

Pseudoxanthoma elasticum, a prototype of heritable multisystem ectopic mineralization disorders, is caused by mutations in the ABCC6 gene encoding a putative efflux transporter, ABCC6. The phenotypic spectrum of pseudoxanthoma elasticum varies, and the correlation between genotype and phenotype has not been established. To identify genetic modifiers, we performed quantitative trait locus analysis in inbred mouse strains that carry the same hypomorphic allele in Abcc6 yet with highly variable ectopic mineralization phenotypes of pseudoxanthoma elasticum. Abcc6 was confirmed as a major determinant for ectopic mineralization in multiple tissues. Integrative analysis using functional genomics tools that included GeneWeaver, String, and Mouse Genome Informatics identified a total of nine additional candidate modifier genes that could influence the organ-specific ectopic mineralization phenotypes. Integration of the candidate genes into the existing ectopic mineralization gene network expands the current knowledge on the complexity of the network that, as a whole, governs ectopic mineralization in soft connective tissues.

Successful human reproduction requires normal spermatogenesis, oogenesis, fertilisation and early embryonic development, and abnormalities in any of these processes will result in infertility. Early embryonic arrest is commonly observed in infertile patients with recurrent failure of assisted reproductive technology (ART). However, the genetic basis for early embryonic arrest is largely unknown.We aim to identify genetic causes of infertile patients characterised by early embryonic arrest.We pursued exome sequencing in a proband with embryonic arrest from the consanguineous family. We further screened candidate genes in a cohort of 496 individuals diagnosed with early embryonic arrest by Sanger sequencing. Effects of mutations were investigated in HeLa cells, oocytes and embryos.We identified five independent individuals carrying biallelic mutations in

Pseudoxanthoma elasticum (PXE), the prototype of heritable ectopic mineralization disorders, manifests with deposition of calcium hydroxyapatite crystals in the skin, eyes and arterial blood vessels. This autosomal recessive disorder, due to mutations in ABCC6, is usually diagnosed around the second decade of life. In the spectrum of heritable ectopic mineralization disorders are also generalized arterial calcification of infancy (GACI), with extremely severe arterial calcification diagnosed by prenatal ultrasound or perinatally, and arterial calcification due to CD73 deficiency (ACDC) manifesting with arterial and juxta-articular mineralization in the elderly; the latter disorders are caused by mutations in ENPP1 and NT5E, respectively. The unifying pathomechanistic feature in these three conditions is reduced plasma levels of inorganic pyrophosphate (PPi), a powerful endogenous inhibitor of ectopic mineralization. Several on-going attempts to develop treatments for these conditions, either with the goal to normalize PPi plasma levels or by means of preventing calcium hydroxyapatite deposition independent of PPi, are in advanced preclinical levels or in early clinical trials. This overview summarizes the prospects of treatment development for ectopic mineralization disorders, with PXE, GACI and ACDC as the target diseases, from the 2020 vantage point.

// Sarah Y. Siu 1 , Nathaniel A. Dyment 2 , David W. Rowe 2 , John P. Sundberg 3 , Jouni Uitto 1,4 and Qiaoli Li 1,4 1 Department of Dermatology and Cutaneous Biology, The Sidney Kimmel Medical College and The PXE International Center of Excellence in Research and Clinical Care, Thomas Jefferson University, Philadelphia, PA, USA 2 Center for Regenerative Medicine and Skeletal Development, University of Connecticut Health Center, Farmington, CT, USA 3 The Jackson Laboratory, Bar Harbor, ME, USA 4 Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, PA, USA Correspondence to: Qiaoli Li, email: // Keywords : ectopic mineralization; generalized arterial calcification of infancy; mouse models; cryohistology; Pathology Section Received : October 07, 2016 Accepted : November 02, 2016 Published : November 14, 2016 Abstract Generalized arterial calcification of infancy (GACI) is an autosomal recessive disorder characterized by early onset of extensive mineralization of the cardiovascular system. The classical forms of GACI are caused by mutations in the ENPP1 gene, encoding a membrane-bound pyrophosphatase/phosphodiesterase that hydrolyzes ATP to AMP and inorganic pyrophosphate. The asj-2J mouse harboring a spontaneous mutation in the Enpp1 gene has been characterized as a model for GACI. These mutant mice develop ectopic mineralization in skin and vascular connective tissues as well as in cartilage and collagen-rich tendons and ligaments. This study examined in detail the temporal ectopic mineralization phenotype of connective tissues in this mouse model, utilizing a novel cryo-histological method that does not require decalcification of bones. The wild type, heterozygous, and homozygous mice were administered fluorescent mineralization labels at 4 weeks (calcein), 10 weeks (alizarin complexone), and 11 weeks of age (demeclocycline). Twenty-four hours later, outer ears, muzzle skin, trachea, aorta, shoulders, and vertebrae were collected from these mice and examined for progression of mineralization. The results revealed differential timeline for disease initiation and progression in various tissues of this mouse model. It also highlights the advantages of cryo-histological fluorescent imaging technique to study mineral deposition in mouse models of ectopic mineralization disorders.

Study question Are genetic variations at the human solute carrier family 18 member A2 (SLC18A2) locus associated with the etiology of polycystic ovary syndrome (PCOS) and/or with follicle stimulating hormone (FSH) levels and insulin secretion in PCOS? Summary answer We found two common genetic variants in the 3'-untranslated region of SLC18A2 (rs363282 and rs363238) that are associated with serum FSH concentration in the PCOS group. What is known already SLC18A2 is a vesicular monoamine transporter that is essential in dopamine regulation. Dopamine can negatively regulate FSH and insulin secretion through the D2 receptor. Study design, size, duration This study was a cross-sectional examination in women with PCOS (n = 319) and controls (n = 220) from China. Participants/materials, setting, methods The PCOS patients were diagnosed based on the criteria of the Androgen Excess Society, including clinical and/or biochemical signs of hyperandrogenemia plus oligoamenorrhea or polycystic ovaries. Controls had regular menstrual cycles and no hyperandrogenism or other endocrine disorders related to PCOS. Tag single nucleotide polymorphisms (SNPs) were selected based on resequencing data in 48 PCOS patients and linkage disequilibrium analysis. Allele frequencies for variants (rs363282 and rs363238) were examined in PCOS cases and controls along with their relationship to quantitative traits. The samples were further divided into two subgroups for association analysis: AA + AG group and GG group (rs363282), CC + AC group and AA group (rs363238). The functional effects of SLC18A2 variants were measured by luciferase assay. The gene expression of SLC18A2 was compared with the NCBI's Gene Expression Omnibus datasets. Main results and the role of chance Two common genetic variants in the 3'-untranslated region (rs363282 and rs363238) are associated with serum FSH in the PCOS group (P= 0.005 and P= 0.001, respectively), while no associations were found in controls. Functional studies showed that minor alleles of the two variants (rs363282-G and rs363238-A) had significantly lower luciferase activities than rs363282-A (P= 0.009) and rs363238-C (P = 0.009). Limitations, reasons for caution Results were not validated in another independent cohort, though we provided functional evidence of the two SNPs. Because of limited condition, more specific parameters, including ovarian follicle count and anti-Mullerian hormone were not included and relationship between SLC18A2 and these parameters cannot be evaluated. Wider implications of the findings We found a novel association between two genetic variants in SLC18A2 and FSH levels in PCOS patients. These findings might indicate a novel regulatory mechanism in follicular development and maturation in PCOS. Study funding/competing interests This work was supported by the National Natural Science Foundation of China (grant numbers 81571501 and 81270747), National Basic Research Program of China (grant number 2015CB943300). No competing interests declared.

Heritable ectopic mineralization disorders represent a phenotypically diverse group of conditions characterized by deposition of calcium phosphate complexes in soft connective tissues. The prototype of such conditions is pseudoxanthoma elasticum (PXE), and related conditions with overlapping clinical features include generalized arterial calcification of infancy (GACI) and arterial calcification due to CD73 deficiency (ACDC). Molecular genetic investigations have revealed mutations in the genes physiologically involved in generation of inorganic pyrophosphate (PPi) and phosphate (Pi), and the findings suggest a unifying pathomechanism relating to reduced PPi/Pi ratio. This hypothesis is based on the notion that PPi serves as a powerful inhibitor of mineralization while Pi is a pro-mineralization factor, and an appropriate PPi/Pi ratio is critical for prevention of ectopic mineralization under homeostatic conditions. PXE International, the premiere patient support organization, advocating on behalf of patients and families with PXE, sponsors regular research meetings evaluating the progress in this and related ectopic mineralization disorders. The latest meetings were held in September 2014 in Bethesda, MD and in September 2015 in Budapest, Hungary. This report summarizes the latest progress in research on PXE and related ectopic mineralization disorders, based on presentations and discussions in these meetings, with pharmacologic implications for currently intractable disorders.

// Jieyu Zhang 1,2 , Nathaniel A. Dyment 3 , David W. Rowe 3 , Sarah Y. Siu 1 , John P. Sundberg 4 , Jouni Uitto 1 and Qiaoli Li 1 1 Department of Dermatology and Cutaneous Biology, The Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA 2 Department of Dermatology, The Fourth Military Medical University, Xijing Hospital, Xi’an, China 3 Center for Regenerative Medicine and Skeletal Development, University of Connecticut Health Center, Farmington, CT, USA 4 The Jackson Laboratory, Bar Harbor, ME, USA Correspondence to: Qiaoli Li, email: // Keywords : ectopic mineralization, tendon and ligament calcification, chondrocalcinosis, generalized arterial calcification of infancy, mouse models, Pathology Section Received : October 22, 2015 Accepted : January 31, 2016 Published : February 17, 2016 Abstract Generalized arterial calcification of infancy (GACI), an autosomal recessive disorder caused by mutations in the ENPP1 gene, manifests with extensive mineralization of the cardiovascular system. A spontaneous asj-2J mutant mouse has been characterized as a model for GACI. Previous studies focused on phenotypic characterization of skin and vascular tissues. This study further examined the ectopic mineralization phenotype of cartilage, collagen-rich tendons and ligaments in this mouse model. The mice were placed on either control diet or the “acceleration diet” for up to 12 weeks of age. Soft connective tissues, such as ear (elastic cartilage) and trachea (hyaline cartilage), were processed for standard histology. Assessment of ectopic mineralization in articular cartilage and fibrocartilage as well as tendons and ligaments which are attached to long bones were performed using a novel cryo-histological method without decalcification. These analyses demonstrated ectopic mineralization in cartilages as well as tendons and ligaments in the homozygous asj-2J mice at 12 weeks of age, with the presence of immature osteophytes displaying alkaline phosphatase and tartrate-resistant acid phosphatase activities as early as at 6 weeks of age. Alkaline phosphatase activity was significantly increased in asj-2J mouse serum as compared to wild type mice, indicating increased bone formation rate in these mice. Together, these data highlight the key role of ENPP1 in regulating calcification of both soft and skeletal tissues.

BackgroundA large schizophrenia genome-wide association study (GWAS) and a subsequent extensive replication study of individuals of European ancestry identified eight new loci with genome-wide significance and suggested that theMIR137-mediated pathway plays a role in the predisposition for schizophrenia.AimsTo validate the above findings in a Han Chinese population.MethodWe analysed the single nucleotide polymorphisms (SNPs) in the newly identified schizophrenia candidate loci and predictedMIR137target genes based on our published Han Chinese populations (BIOX) GWAS data. We then analysed 18 SNPs from the candidate regions in an independent cohort that consisted of 3585 patients with schizophrenia and 5496 controls of Han Chinese ancestry.ResultsWe replicated the associations of five markers (PMIR137target genes. Two loci (ITIH3/4: rs2239547,P=1.17×10–10andCALN1: rs2944829,P=9.97×10–9) exhibited genome-wide significance in the Han Chinese population.ConclusionsTheITIH3/4locus has been reported to be of genome-wide significance in the European population. The successful replication of this finding in a different ethnic group provides stronger evidence for the association between schizophrenia andITIH3/4. We detected the first genome-wide significant association of schizophrenia withCALN1, which is a predicted target ofMIR137, and thus provide new evidence for the associations betweenMIR137targets and schizophrenia.

Pseudoxanthoma elasticum (PXE), a prototype of heritable ectopic mineralization disorders, is an autosomal recessive disease characterized by deposition of calcium hydroxyapatite in the skin, eyes, and cardiovascular system, with protean manifestations (Li et al., 2016; Li and Uitto, 2013; Neldner, 1988). The classic form of PXE is late-onset and slow-progressing, and the major clinical problems relate to loss of vision and development of cardiovascular complications (Neldner, 1988). The classic form of PXE is caused by loss-of-function mutations in the ABCC6 gene encoding ATP-binding cassette subfamily C, member 6 (ABCC6), a putative transmembrane efflux transporter protein expressed primarily in the liver and kidneys. The metabolic hypothesis concerning PXE postulates that the absence of functional ABCC6 activity, primarily in the liver, results in deficiency of circulating factor(s) that is physiologically required to prevent ectopic mineralization under normal calcium and phosphate homeostasis (Li et al., 2016) (Figure 1). However, the factor(s) transported by ABCC6 from the intracellular milieu to the extracellular space have not been identified.

Connexins and pannexins are two protein families that play an important role in cellular communication. Pannexin 1 (PANX1), one of the members of pannexin family, is a channel protein. It is glycosylated and forms three species, GLY0, GLY1, and GLY2. Here, we describe four independent families in which mutations in PANX1 cause familial or sporadic female infertility via a phenotype that we term "oocyte death." The mutations, which are associated with oocyte death, alter the PANX1 glycosylation pattern, influence the subcellular localization of PANX1 in cultured cells, and result in aberrant PANX1 channel activity, ATP release in oocytes, and mutant PANX1 GLY1. Overexpression of a patient-derived mutation in mice causes infertility, recapitulating the human oocyte death phenotype. Our findings demonstrate the critical role of PANX1 in human oocyte development, provide a genetic explanation for a subtype of infertility, and suggest a potential target for therapeutic intervention for this disease.

Human oocyte maturation is a precondition for fertilization and ensuing embryonic development. Previously, we identified TUBB8 variants as a genetic determinant of human oocyte maturation arrest and showed that these variants cause variable and mixed phenotypes in oocyte maturation and early embryo development. We also estimated that rare inherited or de novo variants in the TUBB8 gene accounted for 30% of individuals in a small cohort of patients affected by oocyte maturation arrest. In the present study, we recruited a further 87 patients from unrelated families diagnosed with oocyte maturation or early embryonic arrest and identified 30 patients carrying TUBB8 variants. The corresponding phenotypes not only include oocyte maturation arrest, failure of fertilization, and early embryonic arrest, but also extend to the new phenotype of failure of embryo implantation. These observations provide the most detailed mutational and phenotypic spectrum of TUBB8, further extend the spectrum of variants and dysfunctional oocyte and embryo phenotypes caused by TUBB8 variants, and confirm previous findings for a critical role of TUBB8 during oocyte maturation and early embryonic development. Thus, TUBB8 mutation screening might not only be a genetic diagnostic marker for patients with oocyte maturation arrest, but might also have clinical implications for evaluating the competence of patients’ functional oocytes with first polar body (PB1).

Ectopic mineralization is a global problem and leading cause of morbidity and mortality. The pathomechanisms of ectopic mineralization are poorly understood. Recent studies on heritable ectopic mineralization disorders with defined gene defects have been helpful in elucidation of the mechanisms of ectopic mineralization in general. The prototype of such disorders is pseudoxanthoma elasticum (PXE), a late-onset, slowly progressing disorder with multisystem clinical manifestations. Other conditions include generalized arterial calcification of infancy (GACI), characterized by severe, early-onset mineralization of the cardiovascular system, often with early postnatal demise. In addition, arterial calcification due to CD73 deficiency (ACDC) occurs late in life, mostly affecting arteries in the lower extremities in elderly individuals. These three conditions, PXE, GACI, and ACDC, caused by mutations in ABCC6, ENPP1, and NT5E, respectively, are characterized by reduced levels of inorganic pyrophosphate (PPi) in plasma. Because PPi is a powerful antimineralization factor, it has been postulated that reduced PPi is a major determinant for ectopic mineralization in these conditions. These and related observations on complementary mechanisms of ectopic mineralization have resulted in development of potential treatment modalities for PXE, including administration of bisphosphonates, stable PPi analogs with antimineralization activity. It is conceivable that efficient treatments may soon become available for heritable ectopic mineralization disorders with application to common calcification disorders.

Hassan Vahidnezhad, Mohammadreza Barzegar, Qiaoli Li, Soheila Sotoudeh, Ameneh Yazdanfar, Amir Hooshang Ehsani, Abdol-Mohammad Kajbafzadeh, Nikoo Mozafari, Nasser Ebrahimi Daryani, Farzaneh Agha-hosseini, Sirous Zeinali and Jouni Uitto Tehran University of Medical Sciences, Tehran, Iran; Thomas Jefferson University, Philadelphia, PA, USA; Pasteur Institute of Iran, Tehran, Iran; Shahid Beheshti University of Medical Sciences, Tehran, Iran and Hamedan University of Medical Sciences, Hamedan, Iran E-mail: Jouni.Uitto@jefferson.edu

Next-generation sequencing applied either to the entire genome or to a subset, such as a whole exome, has revolutionized the search for pathogenic mutations in heritable diseases, including genodermatoses. In this issue, Hosen et al. applied whole-exome sequencing to identify potential pathogenic mutations in four candidate genes associated with pseudoxanthoma elasticum, the prototype of ectopic mineralization disorders. The study highlights the advantages of this approach over traditional Sanger sequencing, including expedience and cost, but it also illustrates some of the challenges encountered in implementing this rapidly evolving technology.

Endometriosis is a benign disease, with malignant properties. A necessary step in the progression of endometriosis is tissue remodeling, which is coordinated by the activities of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs). This study evaluated the regulation of abnormal MMP and TIMP gene expression during endometriosis. Among the two genes families, promoter regions of MMP2, MMP3, MMP7, TIMP3, and TIMP4 were significantly altered in proliferative-phase endometriotic lesions compared to menstrual cycle-matched eutopic tissue from endometriosis-free women. In addition, a negative correlation was found between the DNA methylation status of the promoter region and transcript abundance of MMP2. Our findings suggest that changes in DNA methylation at the promoter region of MMP2 could underlie the changes in its expression in the ectopic endometria from patients with endometriosis.

Pseudoxanthoma elasticum (PXE), a prototype of heritable ectopic mineralization disorders, is caused in most cases by inactivating mutations in the ABCC6 gene. It was recently discovered that absence of ABCC6-mediated ATP release from the liver and consequently reduced plasma PPi levels underlie PXE. This study examined whether reduced levels of circulating PPi, an anti-mineralization factor, is the sole mechanism of PXE. The Abcc6(−/−) and Enpp1(asj) mice were crossed with transgenic mice expressing human ENPP1, an ectonucleotidase which generates PPi from ATP. We generated Abcc6(−/−) and Enpp1(asj) mice, either wild type or hemizygous for human ENPP1. Plasma levels of PPi and the degree of ectopic mineralization were determined. Overexpression of human ENPP1 in Enpp1(asj) mice normalized plasma PPi levels to that of wild type mice, and consequently, completely prevented ectopic mineralization. These changes were accompanied with restoration of their bone microarchitecture. In contrast, while significantly reduced mineralization was noted in Abcc6(−/−) mice expressing human ENPP1, small mineralization foci were still evident despite increased plasma PPi levels. These results suggest that PPi is the major mediator of ectopic mineralization in PXE, but there might be an alternative, as-yet unknown mechanism, independent of PPi, by which ABCC6 prevents ectopic mineralization under physiologic conditions.

Immunoglobulin-like domain containing receptor 1 (ILDR1) is a poorly characterized gene that was first identified in lymphoma cells. Recently, ILDR1 has been found to be responsible for autosomal recessive hearing impairment DFNB42. Patients with ILDR1 mutations cause bilateral non-progressive moderate-to-profound sensorineural hearing impairment. However, the etiology and mechanism of ILDR1-related hearing loss remains to be elucidated. In order to uncover the pathology of DFNB42 deafness, we used the morpholino injection technique to establish an ildr1b-morphant zebrafish model. Ildr1b-morphant zebrafish displayed defective hearing and imbalanced swimming, and developmental delays were seen in the semicircular canals of the inner ear. The gene expression profile and real-time PCR revealed down-regulation of atp1b2b (encoding Na(+)/K(+) transporting, beta 2b polypeptide) in ildr1b-morphant zebrafish. We found that injection of atp1b2b mRNA into ildr1b-knockdown zebrafish could rescue the phenotype of developmental delay of the semicircular canals. Moreover, ildr1b-morphant zebrafish had reduced numbers of lateral line neuromasts due to the disruption of lateral line primordium migration. In situ hybridization showed the involvement of attenuated FGF signaling and the chemokine receptor 4b (cxcr4b) and chemokine receptor 7b (cxcr7b) in posterior lateral line primordium of ildr1b-morphant zebrafish. We concluded that Ildr1b is crucial for the development of the inner ear and the lateral line system. This study provides the first evidence for the mechanism of Ildr1b on hearing in vivo and sheds light on the pathology of DFNB42.

Pseudoxanthoma elasticum (PXE), a rare genetic disease caused by mutations in the ABCC6 gene, is characterized by progressive calcification of elastic fibers in the skin, eyes, and the cardiovascular system. The pathomechanism of the mineralization is still obscure. Several hypotheses have been proposed, one of them suggesting a role for fibroblasts in controlling the amount and the quality of the calcified extracellular matrix. This hypothesis raises the question whether changes in mesenchymal cells are the cause and/or the consequences of the calcification process. In this study, fibroblasts were isolated and cultured from Abcc6(+/+) and Abcc6(-/-) mice of different ages to investigate parameters known to be associated with the phenotype of fibroblasts from PXE patients. Results demonstrate that a few changes (Ank and Opn downregulation) are already present before the occurrence of calcification. By contrast, a modification of other parameters (intracellular O2- content, Tnap activity, and Bmp2 upregulation) can be observed in Abcc6(-/-) mice after the onset of tissue mineralization. These data suggest that in the Abcc6(-/-) genotype, dermal fibroblasts actively contribute to changes that promote matrix calcification and that these cells can be further modulated with time by the calcified environment, thus contributing to the age-dependent progression of the disease.

Ectopic mineralization of renal tissues in nephrocalcinosis is a complex, multifactorial process. The purpose of this study was to examine the role of genetic modulation and the role of diet in nephrocalcinosis using two established mouse models of ectopic mineralization, Abcc6(tm1Jfk) and Enpp1(asj) mice, which serve as models for pseudoxanthoma elasticum and generalized arterial calcification of infancy, two heritable disorders, respectively. These mutant mice, when on standard rodent diet, develop nephrocalcinosis only at a very late age. In contrast, when placed on an 'acceleration diet' composed of increased phosphate and reduced magnesium content, they showed extensive mineralization of the kidneys affecting primarily the medullary tubules as well as arcuate and renal arteries, as examined by histopathology and quantitated by chemical assay for calcium. Mineralization could also be detected noninvasively by micro computed tomography. Whereas the heterozygous mice did not develop nephrocalcinosis, compound heterozygous mice carrying both mutant alleles, Abcc6(tm1Jfk/+) and Enpp1(+/asj), developed ectopic mineralization similar to that noted in homozygous mice for either gene, indicating that deletion of one Abcc6 allele along with Enpp1 haploinsufficiency resulted in renal mineralization. Thus, synergistic genetic defects in the complex mineralization/antimineralization network can profoundly modulate the degree of ectopic mineralization in nephrocalcinosis.

Telomeres are specialized chromatin structures located at the ends of eukaryotic chromosomes, and telomere length plays a clear role in various diseases. However, it is not known whether telomere length is related to polycystic ovary syndrome (PCOS).We hypothesized that leukocyte telomere length (LTL) plays an important role in the pathophysiology of PCOS.We used an established and validated quantitative PCR technique to measure the mean LTL in a large sample of PCOS patients and controls. We used logistic regression and multiple linear regression to analyze the association of PCOS and several related clinical parameters with the age-adjusted ratio of the telomere repeat length to the copy number of a single-copy gene (T/S).Individuals with PCOS (n = 698) exhibited significantly shorter LTLs than the controls (n = 611) after adjusting for age (0.764 ± 0.016 vs 0.876 ± 0.023; P = .001; odds ratio = 1.403; 95% confidence interval, 1.150-1.712). The mean telomere length in the leukocytes of PCOS patients was comparable to that of control individuals who were on average 6.16 years older. Individuals having shorter telomere lengths (middle and lowest tertile) had significantly higher disease risk than those having the longest telomere length (highest tertile) (odds ratio = 1.614; 95% confidence interval, 1.262-2.066; P = .0001) after adjusting for age. In addition, a significant correlation between the LTL and the level of dehydroepiandrosterone sulfate was observed in controls (r = -0.185; P = .01).We provide the first report that LTL is strongly associated with PCOS. This study suggests a new role for LTL in the pathophysiology of PCOS and might have important implications for our understanding of the etiology of the disease.

Lipoid proteinosis (LP) is a rare autosomal recessive genodermatosis caused by loss-of-function mutations in the ECM1 gene, and previous studies have noted phenotypic variability. In this study, we examined 12 patients representing three Iranian families for clinical manifestations and genotyped them for mutations in ECM1. LP was diagnosed with characteristic mucocutaneous and neurologic manifestations. Five patients were also subjected to magnetic resonance imaging (MRI)/computed tomography (CT) scan of the central nervous system. DNA was isolated from peripheral blood from patients and their clinically unaffected relatives, and mutations in ECM1 were sought by PCR-based amplification of all exons and flanking intronic sequences, followed by bidirectional Sanger sequencing. Significant phenotypic variability in this multisystem disorder, including presence of convulsions and epilepsy in about half of the patients was noted. In most cases, this was associated with calcifications in the brain detected by MRI/CT scans. Genotyping of the affected individuals in three families from the central region of Iran revealed presence of homozygous c.507delT mutation in ECM1, reflecting the observed consanguinity in these families. This large cohort revealed extensive phenotypic variability in individuals with the same mutation in ECM1. This observation suggests a role for genetic and epigenetic as well as environmental modulation of the phenotype. Identification of mutations allows screening of unaffected individuals for presence or absence of this mutation in extended LP families, with implications for genetic counseling.

Pseudoxanthoma elasticum (PXE) is characterized by aberrant mineralization of connective tissues, causing considerable morbidity and mortality. The disease is typically of late onset, the skin manifestations first being noted in the teens or later. Another aberrant mineralization disorder, generalized arterial calcification of infancy (GACI), is present at birth and can demonstrate a phenotypic overlap with PXE.A patient with PXE was noted to have skin findings as early as at 6 years of age, with cardiovascular involvement. The purpose of this study was to examine the genetic basis of this phenotypic presentation in the spectrum of PXE/GACI.The patient's genotype was studied by sequencing ABCC6 and ENPP1, genes known to be associated with PXE and/or GACI.Screening of the ABCC6 gene revealed two pathogenetic mutations, p.R1141X and g.del23-29. Analysis of the ENPP1 gene failed to demonstrate the presence of mutations.This study demonstrates the presence of cutaneous findings of PXE in an 8-year-old paediatric patient, with cardiovascular involvement, illustrating the phenotypic spectrum of PXE.

Detailed histopathological diagnoses of inbred mouse strains are important for interpreting research results and defining novel models of human diseases. The aim of this study was to histologically detect lesions affecting the KK/HlJ inbred strain. Mice were examined at 6, 12, and 20 months of age and near natural death (ie, moribund mice). Histopathological lesions were quantified by percentage of affected mice per age group and sex. Predominant lesions were mineralization, hyperplasia, and fibro-osseous lesions. Mineralization was most frequently found in the connective tissue dermal sheath of vibrissae, the heart, and the lung. Mineralization was also found in many other organs but to a lesser degree. Hyperplasia was found most commonly in the pancreatic islets, and fibro-osseous lesions were observed in several bones. The percentage of lesions increased with age until 20 months. This study shows that KK/HlJ mice demonstrate systemic aberrant mineralization, with greatest frequency in aged mice. The detailed information about histopathological lesions in the inbred strain KK/HlJ can help investigators to choose the right model and correctly interpret the experimental results.

Ectopic mineralization has been linked to several common clinical conditions with considerable morbidity and mortality. The mineralization processes, both metastatic and dystrophic, affect the skin and vascular connective tissues. There are several contributing metabolic and environmental factors that make uncovering of the precise pathomechanisms of these acquired disorders exceedingly difficult. Several relatively rare heritable disorders share phenotypic manifestations similar to those in common conditions, and, consequently, they serve as genetically controlled model systems to study the details of the mineralization process in peripheral tissues. This overview will highlight diseases with mineral deposition in the skin and vascular connective tissues, as exemplified by familial tumoral calcinosis, pseudoxanthoma elasticum, generalized arterial calcification of infancy, and arterial calcification due to CD73 deficiency. These diseases, and their corresponding mouse models, provide insight into the pathomechanisms of soft tissue mineralization and point to the existence of intricate mineralization/anti-mineralization networks in these tissues. This information is critical for understanding the pathomechanistic details of different mineralization disorders, and it has provided the perspective to develop pharmacological approaches to counteract the consequences of ectopic mineralization.