Non-related Families Research Articles

Analysis of Inherited Optic Neuropathies.

Inherited optic neuropathies (IONs) cover a spectrum of clinically and genetically heterogenic conditions. Genetic evaluation of patients with IONs may enable their better clinico-diagnostic assessment and management of the disease. The aim of the present study was to determine the genetic condition related to the phenotype in patients with diverse inherited optic neuropathies. A retrospective study was performed in 12 adults and 8 children of 8 non-related families. Clinical phenotyping, supported by color fundus, FAF, and OCT imaging, was performed. Genetic testing was obtained for all family members suspected for ION. Identification of pathogenic mutations in eight non-related families helped to confirm the diagnosis of ION. Affected from ION were ten patients (eight adults and two children; four women and six men). Bilateral Leber's hereditary optic neuropathy (LHON) was linked to the m.11778G>A mutation in two families (two affected and five carriers). Secondary homoplasmic LHON mutations in MT-ND1 (m.4216T>C) and MT-CO3 genes (m.9804G>A) were confirmed in two families (each one subject, three eyes affected), without detection of a primary LHON mutation. One member presented a picture of right-sited optic neuropathy associated with a c.220C>G mutation in the ACO2 gene and a heterozygous c.185C>T mutation in the LDLR gene. Autosomal dominant optic atrophy was confirmed in three non-related families (five subjects with bilateral ION), where molecular genetic analyses confirmed four different heterozygous mutations in OPA1: c.1847+1G>T; c.2497-1G>A, 297A>G and c.(2983+1_2984-1)_(c.*3211) (2 splicing mutations, 1 missense mutation, and 1 gross deletion encompassing exons 30 and 31). Combining clinics and molecular genetics when evaluating patients with IONs helps in characterizing disease and, therefore, is strongly recommended for such patients.

First Analysis of SERPING1 Gene in Patients with Hereditary Angioedema in Colombia Reveals Two Genotypic Variants in a Highly Symptomatic Individual.

Hereditary angioedema (HAE) is a heterogeneous genetic disease caused by a deficit in C1 inhibitor (C1-INH) and clinically characterized by sudden events of edema, swelling, and pruritus. Here, we describe the first SERPING1 genotyping in 22 subjects from 4 non-related families, all from southern Colombia. The previously reported heterozygous gene mutations, c.1081C>T (p.Gln361*), c.1396C>G (p.Arg466Gly), c.1029+84G>A, or c.106_107del (p.Ser36Phefs*21), were found in 12 patients. Of note, a single patient clinically characterized as severe HAE type 2 expressed mutations in exon 8 and intron 6, whereas all the others have type 1 HAE and expressed one pathogenic variant. One of the subjects, a 5-year-old girl was discovered to have a pathogenic variant, and sheis still asymptomatic. This is the first report focused on HAE genetic analysis in a Colombian population.

1732P - Descriptive analysis of families with TP53 mutations: Is there a genotype/phenotype correlation?

Background: Li-Fraumeni syndrome (LFS) is a rare and serious hereditary cancer syndrome caused by germline mutations in the TP53 gene. Our objective is to review the molecular and clinical characteristics of our LFS families. Methods: Retrospective descriptive analysis. Molecular germinal diagnosis was done either by Sanger or NG Sequencing (Trusight Cancer, Illumina); Large Genomic rearrangements were tested by MLPA (MRC Holland). Results: Among 4952 non-related families registered in our multidisciplinary program, 395 are BRCA1/2 families and 36 haver other molecular diagnoses with 7/36 confirmed TP53 families. Twenty-nine pts were reviewed, including 2 male carriers, (36, 40 years) that haven’t developed cancers yet. Forty-one tumours were registered (median of 1,41 tumours/carrier, 0–4). Female/male was 2:1. Median age for the first tumour was 24 years (1-45) in the index cases and 35 (1,5-61) in relatives (p > 0,05). Breast cancer (BC) (34% of cancers/48% pts) and sarcomas (31% of cancers/44% pts) were the most common malignancies. For BC cases hormone receptor status was confirmed in 8/14 (positive in 6/8, simultaneous HER2 positivity in 2 cases). Median age of death was 40 (34-58). Most mutations were missense (5 - 2 dominant-negative affecting the DNA binding domain: c.743G>A, p.R248Q and c.725G>A, p.C242Y), none was recurrent and the only frequent mutation observed was c.743G>A, p.R248Q. One of the missense and the 2 frameshift mutations have never been described as germinal: c.481G>A, p.A161T; c.86del, p.N29Tfs*15 and c.990del, p.Q331Rfs*14 Chompret criteria were met in 6/7 (85%) of cases and didn't identitfy a breast cancer only family, with 3 consecutive generations affected. Conclusions: Our data confirms the heterogeneity and complexity of malignancies and mutations in LSF. Breast cancer and sarcomas were the most frequent cancers and missense, non-recurrent mutations were mostly observed. In this study c.481G>A, p.A161T; c.86del, p.N29Tfs*15 and c.990del, p.Q331Rfs*14 are, for the first time, identified as germinal mutations. At this time no genotype-to-phenotype correlation could be confirmed. Chompret’s criteria had only 85% sensitivity for the identification of TP53 families. Legal entity responsible for the study: Instituto Português de Oncologia de Lisboa Francisco Gentil Funding: None Disclosure: J.P. Silva: Travel grants for oncology Congresses: Bristol Meyers-Squibb. All other authors have declared no conflicts of interest.

New genetic causes for complex hereditary spastic paraplegia

IntroductionHereditary Spastic Paraplegia (HSP) represents a complex and heterogeneous group of rare neurodegenerative disorders that share a common clinical feature of weakness and lower limb spasticity that can occur alone or in combination with a constellation of other neurological or systemic signs and symptoms. Although the core clinical feature of weakness and lower limb spasticity is virtually universal, the genetic heterogeneity is almost uncountable with more than 70 genetic forms described so far. We performed review of medical records from twenty-one patients from seventeen Brazilian families with complex phenotype of HSP. All cases have previously negative mutations in SPG11/KIAA1840 and SPG7 gene and were evaluated by whole-exome sequencing. An extensive description of systemic and neurological signs has been described. ResultsWhole-exome sequencing was unremarkable in eight patients and established a definite genetic diagnosis in thirteen patients of twelve non-related families. Mutations were found in genes previously implicated in other neurodegenerative disorders such as Amyotrophic Lateral Sclerosis, Hereditary Neuropathy, Spastic Ataxias, Neurodegeneration with Brain Iron Accumulation, Glycogen Metabolism, Congenital Lipodystrophy and aminoacyl-tRNA synthetases disorders. ConclusionsWe report thirteen new genetically-proven cases of complex HSP, expanding the clinical spectrum of presentations of HSP, providing new pathophysiological mechanisms and disclosing new potential therapeutic targets.

Prominent Optic Disc Featured in Inherited Retinopathy.

Background We investigated the relationship between prominent optic disc (POD) and inherited retinal dystrophy (IRD). Patients and Methods A cross-sectional consecutive study was performed in 10 children and 11 adults of 7 non-related families. We performed clinical phenotyping, including a detailed examination, fundus autofluorescence, and colour fundus and OCT imaging. Genetic testing was subsequently performed for all family members presenting retinal pathology. Results In 4 members of a 3-generation family, hyperfluorescent deposits on the surface of POD were related to a p.(L224M) heterozygous mutation in BEST1. In the second family, one member presented deposits located on the surface on hyperaemic OD and a compound p.(R141H);(A195V) mutation in BEST1. In the third family, POD was observed in father and child with early onset cone-rod dystrophy and a novel autosomal recessive p.(W31*) homozygous mutation in ABCA4. In the fourth family, POD with "mulberry-like" deposits and attenuated vessels were observed in a 7-year old girl, with a mutation in USH1A, and with early onset rod-cone dystrophy, associated with hearing loss. In the fifth family, blurry OD with tortuous vessels was observed in 4 consanguineous female carriers and a hemizygous boy with a p.(R200H) mutation in the X-linked retinoschisis RS1. In the sixth family, a mother and her son were both affected with POD and attenuated peripapillary vessels, and presented with a p.(Y836C) heterozygous mutation in TOPORS, thus confirming autosomal dominant RP. In the seventh family, in 3 family members with POD, compound p.(L541P;A1038 V);(G1961E) mutations in ABCA4 confirmed the diagnosis of Stargardt disease. Conclusions A variety of OD findings are found in a genetically heterogeneous group of IRDs. In the presence of POD, an inherited progressive photoreceptor disease should be ruled out.

Clinical/genetic characteristics of patients with congenital muscular dystrophy caused by mutations in the LMNA gene

To study clinical/genetic characteristics of congenital muscular dystrophy caused by mutations in the LMNA gene in 5 patients from the Russian population. DNA samples of 42 probands, aged from 2 months to 9 years, with characteristic signs of congenital muscular dystrophy from nonrelated families were studied. The diagnosis was based on the results of genealogical analysis, neurological examination, serum creatine phosphokinase activity, results of electroneuromyography. In the Russian population, the frequency of congenital muscular dystrophy caused by mutations in the LMNA gene is not less than 12% of all cases of this group of diseases. The results indicate the presence of major mutation c.94_96delAAC in the LMNA gene. Specific phenotypic features of this form of congenital muscular dystrophy with symptoms of progressive flaccid paralysis with predominant lesions of axial muscles and plantar flexor muscles of the foot are described.

MUTATION SPECTRUM OF THE GENE KCNQ1 IN RUSSIAN PATIENTS WITH LONG QT SYNDROME

The primary long QT syndrome (LQTS) is hereditary disorder of cardiac rhythm. More than 15 genetic types of the disease known. Most prevalent is the type of the disorder related to potassium channel KvLQT1. Aim. Analysis of mutation spectrum in the gene KCNQ1, coding α-subunit of potassium channel IKs, collected with specimens of 143 families with LQTS. Material and methods. Clinical part of the study and LQTS diagnostics included a standard range of personal and family histore, ECG, 24-hour Holter monitoring, EchoCG, long-time passive orthostatic test (tilt-test) if indicated. DNA-diagnostics of mutations in the gene KCNQ1 was performed with the method of direct authomatic sequencing by Sanger. Results. LQTS, type 1, was verified in 53 families (37%). There were 39 mutations revealed in the gene KCNQ1. Most mutations were found once per family, only 4 mutations repeated in 3 or more non-related families. Most prevalent mutation c.477+1G>A in heterozygous kind presents with milder course of the disease. Second by prevalence mutation replacement p.A341V points on serious prognosis of the disease and might be regarded as genetic factor of SCD. Relative predominance of mutations was found for exones 2, 5, 6, 7, 8 of gene KCNQ1. About 20% of mutations appeared de novo. Two non-related mutations were found in 5 families (3,5%) probands. In all cases the carriers of two mutations the disease had worse course, than in one mutation carriage. Conclusion. The data on genetic nature of the disease and clinical signs of various mutations in LQTS can be applied for planning of dynamic follow-up and tactics of antiarrhythmic therapy.

Dysferlinopathy in Switzerland: clinical phenotypes and potential founder effects

BackgroundDysferlin is reduced in patients with limb girdle muscular dystrophy type 2B, Miyoshi myopathy, distal anterior compartment myopathy, and in certain Ethnic clusters.MethodsWe evaluated clinical and genetic patient data from three different Swiss Neuromuscular Centers.ResultsThirteen patients from 6 non-related families were included. Age of onset was 18.8 ± 4.3 years. In all patients, diallelic disease-causing mutations were identified in the DYSF gene. Nine patients from 3 non-related families from Central Switzerland carried the identical homozygous mutation, c.3031 + 2T>C. A possible founder effect was confirmed by haplotype analysis. Three patients from two different families carried the heterozygous mutation, c.1064_1065delAA. Two novel mutations were identified (c.2869C>T (p.Gln957Stop), c.5928G>A (p.Trp1976Stop)).ConclusionsOur study confirms the phenotypic heterogeneity associated with DYSF mutations. Two mutations (c.3031 + 2T>C, c.1064_1065delAA) appear common in Switzerland. Haplotype analysis performed on one case (c. 3031 + 2T>C) suggested a possible founder effect.

Protein phosphatase 2A regulatory subunits affecting plant innate immunity, energy metabolism, and flowering time – joint functions among B'η subfamily members

Protein phosphatase 2A (PP2A) is a heterotrimeric complex comprising a catalytic, scaffolding, and regulatory subunit. The regulatory subunits are essential for substrate specificity and localization of the complex and are classified into B/B55, B', and B” non-related families in higher plants. In Arabidopsis thaliana, the close paralogs B'η, B'θ, B'γ, and B'ζ were further classified into a subfamily of B' called B'η. Here we present results that consolidate the evidence for a role of the B'η subfamily in regulation of innate immunity, energy metabolism and flowering time. Proliferation of the virulent Pseudomonas syringae in B'θ knockout mutant decreased in comparison with wild type plants. Additionally, B'θ knockout plants were delayed in flowering, and this phenotype was supported by high expression of FLC (FLOWERING LOCUS C). B'ζ knockout seedlings showed growth retardation on sucrose-free medium, indicating a role for B'ζ in energy metabolism. This work provides insight into functions of the B'η subfamily members, highlighting their regulation of shared physiological traits while localizing to distinct cellular compartments.

Epidemiological, clinical, and molecular characterization of Cuban families with spinocerebellar ataxia type 3/Machado-Joseph disease.

BackgroundSpinocerebellar Ataxia Type 3/Machado-Joseph Disease (SCA3/MJD) is a hereditary neurodegenerative disorder resulting from the expansion of CAG repeats in the ATXN3 gene. It is the most common autosomal dominant ataxia in the world, but its frequency prevalence in Cuba remains uncertain. We undertook a national study in order to characterize the ATXN3 gene and to determine the prevalence of SCA3/MJD in Cuba.ResultsTwenty-two individuals belonging to 8 non-related families were identified as carriers of an expanded ATXN3 allele. The affected families come from the central and western region of the country. Ataxia of gait was the initial symptom in all of the cases. The normal alleles ranged between 14 and 33 CAG repeats while the expanded ones ranged from 63 to 77 repeats. The mean age at onset was 40 ± 9 years and significantly correlated with the number of CAG repeats in the expanded alleles.ConclusionsThis disorder was identified as the second most common form of spinocerebellar ataxia (SCA) in Cuba based on molecular testing, and showing a different geographical distribution from that of SCA2. This research constitutes the first clinical and molecular characterization of Cuban SCA3 families, opening the way for the implementation of predictive diagnosis for at risk family members.

Frequency of COL4A3/COL4A4 mutations amongst families segregating glomerular microscopic hematuria and evidence for activation of the unfolded protein response. Focal and segmental glomerulosclerosis is a frequent development during ageing.

Familial glomerular hematuria(s) comprise a genetically heterogeneous group of conditions which include Alport Syndrome (AS) and thin basement membrane nephropathy (TBMN). Here we investigated 57 Greek-Cypriot families presenting glomerular microscopic hematuria (GMH), with or without proteinuria or chronic kidney function decline, but excluded classical AS. We specifically searched the COL4A3/A4 genes and identified 8 heterozygous mutations in 16 families (28,1%). Eight non-related families featured the founder mutation COL4A3-p.(G1334E). Renal biopsies from 8 patients showed TBMN and focal segmental glomerulosclerosis (FSGS). Ten patients (11.5%) reached end-stage kidney disease (ESKD) at ages ranging from 37-69-yo (mean 50,1-yo). Next generation sequencing of the patients who progressed to ESKD failed to reveal a second mutation in any of the COL4A3/A4/A5 genes, supporting that true heterozygosity for COL4A3/A4 mutations predisposes to CRF/ESKD. Although this could be viewed as a milder and late-onset form of autosomal dominant AS, we had no evidence of ultrastructural features or extrarenal manifestations that would justify this diagnosis. Functional studies in cultured podocytes transfected with wild type or mutant COL4A3 chains showed retention of mutant collagens and differential activation of the unfolded protein response (UPR) cascade. This signifies the potential role of the UPR cascade in modulating the final phenotype in patients with collagen IV nephropathies.

Hereditary Angioedema in Greece: The First Results of the Greek Hereditary Angioedema Registry

Background: No published data presently exist concerning hereditary angioedema (HAE) in Greece. The aim of this study was to present the results from patients recorded by the Greek Hereditary Angioedema Registry over the last 3 years (July 2010 to June 2013). Methods: A systematic recording of HAE cases was undertaken following a physician awareness campaign and confirmation of diagnosis. A questionnaire was also used for the assessment of key parameters of the patients' disease-specific quality of life. Results: One hundred and sixteen patients from 41 non-related families were recorded. There were 33 (80.5%) families with type I HAE, 7 (17%) with type II HAE and 1 (2.5%) with non-C1 inhibitor (C1-INH), non-FXII HAE. Two further non-C1-INH, non-FXII HAE sporadic cases were recorded. An investigation of non-symptomatic family members revealed another 6 asymptomatic individuals with C1-INH deficiency. The average delay in diagnosis was 16.5 years and the incidence of death in the families of patients was 1 for every 2 families. The use of newer therapeutic agents seems to fall significantly short of the existing needs. HAE was found to affect the quality of life slightly in 14%, greatly in 63% and significantly in 23% of the patients. Conclusion: Until recently, there has been a significant degree of underdiagnosis of HAE in Greece. Very low compliance with the provisions of the applicable international guidelines and consensus positions, with adverse consequences on the patients' quality of life, was also observed. The centralized model we used to uncover the patients could be effective in other countries presenting with comparable disease characteristics. © 2014 S. Karger AG, Basel

In a Field of Party Walls

When Deng Xiaoping initiated market reforms in 1978, reopening the country and inviting the newest phase of foreign investment in Chinese cities, the structure and scale of these cities changed dramatically. Today, the governing process rewards the official who can most rapidly transform his or her city into guoji dadushi , a “great international city.”1 With an unprecedented release of capital,2 China has built more—more skyscrapers and high-rises, more housing and malls, more rail systems and highways—than any other country in a thirty-year period.3 In Shanghai, the traditional lilong (alleyway or lane) housing compounds are being replaced by new gated communities of luxury housing towers surrounded by landscaped parks or paved parking (Figure 1). Widened streets, elevated highways, and spiraling approach ramps to suspension bridges impose a new, vehicular, logic on the city (Figure 2). On its expanding edges, rows upon rows of repetitive housing blocks are organized by an economic logic of mass reproduction and the strict daylight standards that govern the spacing of buildings to ensure that sunlight penetrates residential spaces. Along what were once tow roads running beside canals, new shopping malls have organized their indoor public spaces according to the logic of retailing rather than that of public streets. Figure 1 Aerial view of Shanghai, 2004 (author’s photo) Figure 2 Aerial view of Puxi from Pudong, 2012. The sense of the Huangpu River in the city is now understood only from the heights of new skyscrapers (author’s photo) Developers, to ensure that each project announces itself as an icon, intentionally dissociate it from its surrounding context. Each building is a discrete object whose separation from other buildings is more important than the relation between them. Spaces between buildings are undefined and cars dominate public space. Urbanism is fragmented as identity is transferred from the city to its …

Understanding the relative contributions of direct environmental effects and passive genotype–environment correlations in the association between familial risk factors and child disruptive behavior disorders

Previous work reports an association between familial risk factors stemming from parental characteristics and offspring disruptive behavior disorders (DBDs). This association may reflect (a) the direct effects of familial environment and (b) a passive gene-environment correlation (r(GE)), wherein the parents provide both the genes and the environment. The current study examined the contributions of direct environmental influences and passive r(GE) by comparing the effects of familial risk factors on child DBDs in genetically related (biological) and non-related (adoptive) families. Participants were 402 adoptive and 204 biological families. Familial environment was defined as maternal and paternal maladaptive parenting and antisociality, marital conflict and divorce; offspring DBDs included attention deficit hyperactivity disorder (ADHD), conduct disorder (CD) and oppositional defiant disorder (ODD). Mixed-level regressions estimated the main effects of familial environment, adoption status and the familial environment by adoption status interaction term, which tested for the presence of passive r(GE). There was a main effect of maternal and paternal maladaptive parenting and marital discord on child DBDs, indicating a direct environmental effect. There was no direct environmental effect of maternal or paternal antisociality, but maternal and paternal antisociality had stronger associations with child DBDs in biological families than adoptive families, indicating the presence of a passive r(GE). Many familial risk factors affected children equally across genetically related and non-related families, providing evidence for direct environmental effects. The relationship of parental antisociality and offspring DBDs was best explained by a passive r(GE), where a general vulnerability toward externalizing psychopathology is passed down by the parents to the children.

1H-MR spectroscopy of adult-onset autosomal dominant leukodystrophy with autonomic symptoms

Adult-onset ADLD with autonomic symptoms is a rare disease with a clinical course somewhat similar to chronic progressive MS but with different imaging findings consisting of extensive white matter changes in the cerebrum and cerebellar peduncles. Patients usually present in the fourth to sixth decade with autonomic symptoms, manifesting later symptoms from the pyramidal tracts and ataxia. Here, we present magnetic resonance spectroscopy (MRS) findings in this disease. Fourteen subjects, from two non-related families, with genetic linkage to the disease were studied with magnetic resonance imaging and single-voxel MRS. Clinically, they ranged from asymptomatic to wheelchair-using. Their results were compared to those of age- and sex-matched healthy controls. One MRS was excluded due to suboptimal quality. The remaining 13 subjects manifested characteristic evidence of pathology on MRI, 11 of them exhibited extensive changes. The metabolite concentrations of total Cr, total Cho, and total NAA measured in millimolars, using internal water as a reference, were significantly lower in these 11 subjects compared to controls, and we found linear correlations between all these metabolite levels. When total Cr was used as a reference, we found no difference between subjects and controls. No lactate was detected. The decreased metabolite concentrations measured using internal water as a reference are most likely due to increased water content in the tissues, diluting all metabolites to a similar degree. This is also in agreement with the high signal intensity exhibited in the white matter on T2-weighted MR images and with the reported histopathological findings of vacuolated myelin.

Endocrine Profile and Phenotype-(Epi)Genotype Correlation in Spanish Patients with Pseudohypoparathyroidism

Recent advances in genetics and epigenetics have revealed an overlap between molecular and clinical features of pseudohypoparathyroidism (PHP) subtypes, broadening the previous spectrum of PHP genotype-phenotype correlations and indicating limitations of the current classification of the disease. The aim of the study was to screen patients with clinical diagnoses of PHP type I or pseudo-PHP for underlying molecular defects and explore possible correlations between molecular findings and clinical features. We investigated the GNAS locus at the molecular level in 72 affected patients (46 women and 26 men) from 56 nonrelated families. Clinical data were obtained for 63 of these patients (38 women and 25 men). The molecular analysis showed that 35 patients carried structural mutations, 32 had loss of methylation, and 2 had a 2q37 deletion but did not reveal any (epi)mutation for 3 patients. Comparing these results and the clinical data, we observed that a younger age at diagnosis was associated with structural defects at the GNAS gene and epigenetic defects with a diagnosis later in life (9.19 ± 1.64 vs 24.57 ± 2.28 years, P < .0001). This first global review of PHP in Spain highlights the importance of a detailed clinical and genetic study of each patient and the integrated analysis of the findings from the two approaches. It may also help geneticists and clinicians to raise the suspicion of PHP earlier, reach more accurate diagnoses, and provide patients with PHP and their families with useful genetic information and counseling, thereby improving outcomes and quality of life.

Identification of Two Novel Mutations in TRPS1 Gene in Families With Tricho-Rhino-Phalangeal Type I Syndrome

BackgroundAutosomal dominant tricho-rhino-phalangeal syndrome I (TRPS I) is due to mutations in the TRPS1 gene. Tricho-rhino-phalangeal syndrome I is characterized by peculiar face and skeletal anomalies. Cone-shaped epiphyses are the...

SERPING1 mutations in 59 families with hereditary angioedema

Hereditary angioedema due to C1 Inhibitor (C1Inh) deficiency (HAE types I and II) is a rare, life-threatening disease causing spontaneous edema of the submucosal layers.A cohort of 127 individuals with symptoms of recurrent familial angioedema from 59 non-related families was studied. All the patients included fulfilled the diagnostic and biochemical criteria of HAE, including low C1Inh function and/or concentration. Genetic studies were carried out by PCR and sequencing of the C1NH locus followed, in the negative cases, by MLPA, long-range PCR and restriction enzyme analysis of genomic DNA to detect potential large rearrangements. Mutations located in consensus splicing sequences or nearby positions were studied by RT-PCR.The study identified 52 different mutations (25 missense, 15 frameshift, 7 splicing defects and 5 large deletions) responsible for the disease in 56 HAE families. In the remaining three families no molecular alteration could be detected. Twenty-seven of the mutations in this cohort are novel and 10 are confirmed de novo cases. The pathologic effect of the 5 splicing defects first reported here was assessed at the RNA and protein levels. Large deletions affecting exons 4 and 7, ranging from approximately 1500 to 2500bp, were partially characterized by their altered restriction patterns upon long-range amplification.These results highlight the heterogeneity of mutations in the C1NH gene causing C1Inh deficiency and HAE. An approach to the molecular effects associated to each of the mutations reported here was made when possible based on the available data of pathological variants of serpins.

Protein phosphatase 2A regulatory subunits are starting to reveal their functions in plant metabolism and development

Canonical protein phosphatase 2A (PP2A) consists of a catalytic subunit (C), a scaffolding subunit (A), and a regulatory subunit (B). The B subunits are believed to confer substrate specificity and cellular localization to the PP2A complex, and are generally divided into three non-related families in plants, i.e., B55, B’ and B’’. The two Arabidopsis B55 subunits (α and β) interact with nitrate reductase (NR) in the bimolecular fluorescence complementation assay in planta, and are necessary for rapid activation of NR. Interestingly, knockout of all four B55 alleles is probably lethal, because a homozygous double knockout (pp2a-b55αβ) could not be found. The B55 subunits, therefore, appear to have essential functions that cannot be replaced by other regulatory B subunits. A double mutant (pp2a-b’αβ) of two close B’ homologs show severely impaired fertility, pointing to the essential role also of B’ subunits in plant development.

A multidisciplinary approach for the diagnosis of hypocalcified amelogenesis imperfecta in two Chilean families

Objective. The purpose of this study was to conduct a multidisciplinary analysis of a specific type of tooth enamel disturbance (amelogenesis imperfecta) affecting two Chilean families to obtain a precise diagnosis and to investigate possible underlying mutations. Materials and methods. Two non-related families affected with amelogenesis imperfecta were evaluated with clinical, radiographic and histopathological methods. Furthermore, pedigrees of both families were constructed and the presence of eight mutations in the enamelin gene (ENAM) and three mutations in the enamelysin gene (MMP-20) were investigated by PCR and direct sequencing. Results. In the two affected patients, the dental malformation presented as soft and easily disintegrated enamel and exposed dark dentin. Neither of the affected individuals presented with a dental and skeletal open bite. Histologically, a high level of an organic matrix with prismatic organization was found. Genetic analysis indicated that the condition is autosomal recessive in one family and either autosomal recessive or due to a new mutation in the other family. Molecular mutational analysis revealed that none of the eight mutations previously described in the ENAM gene or the three mutations in the MMP-20 gene were present in the probands. Conclusion. A multidisciplinary analysis allowed for a diagnosis of hypocalcified amelogenesis imperfecta, Witkop type III, which was unrelated to previously described mutations in the ENAM or MMP-20 genes.