Organ Donation from Patients with a Rare Disease is Often Safe: The Italian Guidelines

Although a disease is defined as rare when it has a prevalence of less than 1: 2000, the overall prevalence of rare diseases in the population is greater than 1%. Among potential organ donors, a similar frequency is observed. To date, guidelines have not been established, and operational decisions have been made empirically, case- by-case, based on the experience and expertise of clinicians. For this reason, the Italian Superior Health Council (CSS) has appointed a working Group to address "patients with a rare disease as potential organ donors", with the aim of devising recommendations for the management of transplant cases in which the donors have a rare disease. This group evaluated 493 diseases (10% of all rare diseases, including over 95% of patients with a rare disease) to deliver a technical report dealing with the suitability of organ donation and transplantation, with a focus on the organs most frequently used, including kidney, liver, heart, lung, and pancreas. This work has made it clear that a rare disease "per se" does not contraindicate organ donation at all. Indeed, in donors affected by a rare disease, almost 80% of the organs are suitable for transplantation, approximately 7% are unsuitable, and approximately 14% are suitable as non-standard with an acceptable risk. This article is protected by copyright. All rights reserved.

Use of DPB1 T-cell epitope algorithm among italian transplant centers: A survey on behalf of Associazione Italiana di Immunogenetica e Biologia dei Trapianti

The HLA-DPB1 locus has been demonstrated to have a significant role on patients' outcome after allogeneic HSCT, and the so-called T-cell epitope (TCE) algorithm has been incorporated in international guidelines for the selection of unrelated donors. The purpose of the present study is to measure, through a national survey conducted on behalf of the Associazione Italiana di Immunogenetica e Biologia dei Trapianti (AIBT), the extent of awareness and use of HLA-DPB1 TCE-based algorithms during the donor search. 89% of the HLA laboratories answered to a short questionnaire and the results showed a progressive increase of the laboratories typing DPB1 in patients and their potential donors during the search (from 44% to 79% during the 2010-2019 period) as well as the application of a TCE-based algorithm for the donor choice whenever possible (from 24% to 65% during the same period). The DP-permissiveness status is detailed in the official HLA typing report by 12%, 32% and 50% of laboratories in 2010, 2015 and 2019, respectively. The present data indicate an encouraging raise in the awareness of the HLA-DPB1 role in unrelated donor selection; noteworthy, mentioning the TCE-based permissiveness status in the HLA typing report of each potential unrelated donor represents a notable mean to raise awareness among transplant physicians and to support them in their task of choosing the best donor. Nonetheless, despite the compelling evidence of the predictive ability of TCE-based algorithms, further efforts are still needed to extend its application to all transplant centers in Italy.

Entropy of human leukocyte antigen and killer-cell immunoglobulin-like receptor systems in immune-mediated disorders: A pilot study on multiple sclerosis

Background

Entropy is a thermodynamic variable statistically correlated with the disorder of a system. The hypothesis that entropy can be used to identify potentially unhealthy conditions was first suggested by Schrödinger, one of the founding fathers of quantum mechanics. Shannon later defined entropy as the quantity of information stored in a system. Shannon’s entropy has the advantage of being adaptable across a variety of disciplines, including genetic studies on complex immunogenetic systems such as the human leukocyte antigen (HLA) and killer-cell immunoglobulin-like receptor (KIR) systems.

Methods

In our study, entropy associated to the HLA and KIR systems was compared between a cohort of 619 Sardinian healthy controls and a group of 270 patients affected by multiple sclerosis (MS), the latter stratified into 81 patients with primary progressive multiple sclerosis (PPMS) and 189 patients with relapsing remitting multiple sclerosis (RRMS).

Results

The entropy associated to HLA four-loci haplotypes (A, B, C, DR) and combinations of two inhibitory KIR genes was significantly higher in patients affected by RRMS than in healthy controls. No significant differences were observed for patients with PPMS. By calculating the total HLA and KIR entropy ratio in each subject, it was possible to determine the individual risk of developing MS, particularly RRMS.

Conclusions

In addition to the standard statistical methods used to evaluate immunogenetic parameters associated to immune-mediated disease, the analysis of entropy measures the global disorder status deriving from these parameters. This innovative approach may represent a useful complementary tool to the risk assessment of immune-mediated disorders. Improved risk assessment is particularly important for family members of patients with MS. However, further investigation is warranted to confirm our findings and to evaluate the validity of the entropy-based method in other types of immune-mediated disorders.

Whole Genome Expression Analyses of miRNAs and mRNAs Suggest the Involvement of miR-320a and miR-155-3p and their Targeted Genes in Lithium Response in Bipolar Disorder

Lithium is the mainstay in the maintenance of bipolar disorder (BD) and the most efficacious pharmacological treatment in suicide prevention. Nevertheless, its use is hampered by a high interindividual variability and important side effects. Genetic and epigenetic factors have been suggested to modulate lithium response, but findings so far have not allowed identifying molecular targets with predictive value. In this study we used next generation sequencing to measure genome-wide miRNA expression in lymphoblastoid cell lines from BD patients excellent responders (ER, n = 12) and non-responders (NR, n = 12) to lithium. These data were integrated with microarray genome-wide expression data to identify pairs of miRNA/mRNA inversely and significantly correlated. Significant pairs were prioritized based on strength of association and in-silico miRNA target prediction analyses to select candidates for validation with qRT-PCR. Thirty-one miRNAs were differentially expressed in ER vs. NR and inversely correlated with 418 genes differentially expressed between the two groups. A total of 331 of these correlations were also predicted by in-silico algorithms. miR-320a and miR-155-3p, as well as three of their targeted genes (CAPNS1 (Calpain Small Subunit 1) and RGS16 (Regulator of G Protein Signaling 16) for miR-320, SP4 (Sp4 Transcription Factor) for miR-155-3p) were validated. These miRNAs and mRNAs were previously implicated in psychiatric disorders (miR-320a and SP4), key processes of the central nervous system (CAPNS1, RGS16, SP4) or pathways involved in mental illnesses (miR-155-3p). Using an integrated approach, we identified miRNAs and their targeted genes potentially involved in lithium response in BD.

Wilson's disease: A new perspective review on its genetics, diagnosis and treatment

Wilson's disease (WD) is an autosomal recessive disorder which is caused by poor excretion of copper in mammalian cells. In this review, various issues such as effective characterization of ATP7B genes, scope of gene network topology in genetic analysis, pattern recognition using different computing approaches and fusion possibilities in imaging and genetic dataset are discussed vividly. We categorized this study into three major sections: (A) WD genetics, (B) diagnosis guidelines and (3) treatment possibilities. We addressed the scope of advanced mathematical modelling paradigms for understanding common genetic sequences and dominating WD imaging biomarkers. We have also discussed current state-of-the-art software models for genetic sequencing. Further, we hypothesized that involvement of machine and deep learning techniques in the context of WD genetics and image processing for precise classification of WD. These computing procedures signify changing roles of various data transformation techniques with respect to supervised and unsupervised learning models.

Nonlinear model for the carotid artery disease 10-year risk prediction by fusing conventional cardiovascular factors to carotid ultrasound image phenotypes: A Japanese diabetes cohort study

MOTIVATION

This study presents a novel nonlinear model which can predict 10-year carotid ultrasound image-based phenotypes by fusing nine traditional cardiovascular risk factors (ethnicity, gender, age, artery type, body mass index, hemoglobin A1c, hypertension, low-density lipoprotein, and smoking) with five types of carotid automated image phenotypes (three types of carotid intima-media thickness (IMT), wall variability, and total plaque area).

METHODOLOGY

Two-step process was adapted: First, five baseline carotid image-based phenotypes were automatically measured using AtheroEdge^™ (AtheroPoint^™ , CA, USA) system by two operators (novice and experienced) and an expert. Second, based on the annual progression rates of cIMT due to nine traditional cardiovascular risk factors, a novel nonlinear model was adapted for 10-year predictions of carotid phenotypes.

RESULTS

Institute review board (IRB) approved 204 Japanese patients' left/right common carotid artery (407 ultrasound scans) was collected with a mean age of 69 ± 11 years. Age and hemoglobin were reported to have a high influence on the 10-year carotid phenotypes. Mean correlation coefficient (CC) between 10-year carotid image-based phenotype and age was improved by 39.35% in males and 25.38% in females. The area under the curves for the 10-year measurements of five phenotypes IMT_ave10yr , IMT_max10yr , IMT_min10yr , IMTV_10yr , and TPA_10yr were 0.96, 0.94, 0.90, 1.0, and 1.0. Inter-operator variability between two operators showed significant CC (P < 0.0001).

CONCLUSIONS

A nonlinear model was developed and validated by fusing nine conventional CV risk factors with current carotid image-based phenotypes for predicting the 10-year carotid ultrasound image-based phenotypes which may be used risk assessment.

A Case of Classical Kaposi's Sarcoma in B-Cell Chronic Lymphocytic Leukemia (B-CLL)

We report a case of classical Kaposi's sarcoma (KS) in a patient affected by B-cell chronic lymphocytic leukemia for 2 years and who had not received any antiblastic treatment. At the ultrastructural analysis the leukemic cell showed rather immature features, and the immunologic phenotype (absence of detectable cytoplasmic Ig, and expression only of the DR, B2 and IgDλ molecules on the surface membrane) proved its intermediate level of maturity, its monoclonality and relative rarity. The patient presented a complex immunologic deficiency, revealed not only by the monoclonality of the B lymphocytes and their low degree of maturity, but also by the almost total absence of T helper lymphocytes, by the high reduction in NK activity, by the very scarce proliferative response to the polyclonal mitogens PHA, ConA and PWM, and by a complete anergy to the skin test of delayed reactivity. The search for antibodies against the viruses EBV, CMV, HTLV-I and HTLV-III in the serum was negative. At the HLA typing, the patient was DR5, as are most classical KS and/or B-CLL patients. The data are discussed in relation to documented non-casual association between B-CLL and KS. We stress that immunosuppression may play an important role in the pathogenesis of both diseases and the possibility of their being conditioned by common genetic HLA-associated factors of predisposition.

Reduced stress granule formation and cell death in fibroblasts with the A382T mutation of TARDBP gene: evidence for loss of TDP-43 nuclear function

TAR deoxyribonucleic acid-binding protein 43 (TDP-43) is a key protein in the pathogenesis of amyoptrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Recent studies suggest that mutations in the TDP-43 coding gene, TARDBP, as well as variations in TDP-43 protein expression levels may disrupt the dynamics of stress granules (SGs). However, it remains unclear whether the pathogenetic effect of the TDP-43 protein is exerted at the cytoplasmic level, through direct participation to SG composition, or at nuclear level, through control of proteins essential to SG assembly. To clarify this point, we investigated the dynamics of SG formation in primary skin fibroblast cultures from the patients with ALS together with the A382T mutation and the patients with ALS and healthy controls with wild-type TDP-43. Under stress conditions induced by sodium arsenite, we found that in human fibroblasts TDP-43 did not translocate to the SGs but instead contributed to the SG formation through a regulatory effect on the G3BP1 core protein. We found that the A382T mutation caused a significant reduction in the number of SGs per cell (P < 0.01) as well as the percentage of cells that form SGs (P < 0.00001). Following stress stimuli, a significant decrease of viability was observed for cells with the TDP-43 A382T mutation (P < 0.0005). We can therefore conclude that the A382T mutation caused a reduction in the ability of cells to respond to stress through loss of TDP-43 function in SG nucleation. The pathogenetic action revealed in our study model does not seem to be mediated by changes in the localization of the TDP-43 protein.

A genetic epidemiology study of congenital adrenal hyperplasia in Italy

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency (21OHD-CAH) is an autosomal recessive disorder affecting steroidogenesis, due to mutations in CYP21A2 (6p21.3). 21OHD-CAH neonatal screening is based on 17-hydroxyprogesterone (17OHP) serum levels, showing high type I error rate and low sensitivity to mild CAH forms. Here, we used an epidemiological approach, which estimates the allelic frequency (q) of an autosomal recessive disorder using the proportion of homozygous patients, the mutational spectrum and the inbreeding coefficient in a sample of affected individuals. We applied this approach to 2 independent Italian cohorts of patients with both clinical and molecular diagnosis of 21OHD-CAH from mainland Italy (N = 240) and Sardinia (N = 53). We inferred q estimates of 2.87% and 1.83%, corresponding to a prevalence of 1/1214 and 1/2986, respectively. CYP21A2 mutational spectra were quite discrepant between the 2 cohorts, with V281L representing 74% of all the mutations detected in Sardinia vs 37% in mainland Italy. These findings provide an updated fine-grained picture of 21OHD-CAH genetic epidemiology in Italy and suggest the need for a screening approach suitable to the detection of the largest number of clinically significant forms of CAH.

KIR and their HLA Class I ligands: Two more pieces towards completing the puzzle of chronic rejection and graft loss in kidney transplantation

BACKGROUND

Kidney transplantation is a life-saving treatment for patients with end-stage renal disease. However, despite progress in surgical techniques and patient management, immunological rejection continues to have a negative impact on graft function and overall survival. Incompatibility between donors and recipients for human leukocyte antigens (HLA) of the major histocompatibility complex (MHC) generates a series of complex cellular and humoral immune response mechanisms that are largely responsible for rejection and loss of graft function. Within this context, a growing amount of evidence shows that alloreactive natural killer (NK) cells play a critical role in the immune response mechanisms elicited by the allograft. Killer immunoglobulin-like receptors (KIRs) are prominent mediators of NK cell alloreactivity.

METHODS AND FINDINGS

A cohort of 174 first cadaveric kidney allograft recipients and their donors were selected from a total cohort of 657 transplanted patients for retrospective immunogenetic analyses. Patients with HLA Class II mismatches were excluded. HLA Class I allele frequencies were compared among patients with chronic rejection, patients with stable graft function and a group of 2388 healthy controls. Activating and inhibitory KIR gene frequencies, KIR haplotypes, KIR-HLA ligand matches/mismatches and combinations of recipient KIRs and donor HLA Class I ligands were compared among patients with and without chronic rejection and a group of 221 healthy controls. Patients transplanted from donors homozygous for HLA-C1 antigens had a significantly higher risk for chronic rejection than patients transplanted from donors homozygous or heterozygous for HLA-C2 antigens or with epitopes belonging to the HLA-Bw4 ligand group. The Kaplan-Meier curves obtained by dividing the patients into 3 groups according to the presence or absence of one or both of the combinations of recipient KIRs and donor HLA ligands (rKIR2DL1/dHLA-C2 and rKIR3DL1/dHLA-Bw4) showed a significantly higher cumulative incidence of chronic rejection in the group of patients completely lacking these functional units. These patients showed a progressively stronger decline in modification of diet in renal disease-estimated glomerular filtration rate.

CONCLUSIONS

KIR genotyping should be performed at the time of enrolment of patients on the waiting list for organ transplantation. In our study, a significantly higher risk of chronic rejection after kidney transplantation was observed when recipient (r) and donor (d) pairs completely lacked the two functional rKIR-dHLA ligand combinations rKIR2DL1/dHLA-C2 and rKIR3DL1/dHLA-Bw4. This immunogenetic profile corresponds to low levels of NK cell inhibition. Therefore, patients with this high risk profile could benefit from immunosuppressive therapy aimed at reducing NK-cell cytotoxicity.

HLA-G expression and role in advanced-stage classical Hodgkin lymphoma

Non-classical human leucocyte antigen (HLA)-G class I molecules have an important role in tumor immune escape mechanisms. We investigated HLA-G expression in lymphonode biopsies taken from 8 controls and 20 patients with advanced-stage classical Hodgkin lymphoma (cHL), in relationship to clinical outcomes and the HLA-G 14-basepair (14-bp) deletion-insertion (del-ins) polymorphism. Lymphnode tissue sections were stained using a specific murine monoclonal HLA-G antibody. HLA-G protein expression was higher in cHL patients than controls. In the group of PET-2 positive (positron emission tomography carried out after 2 cycles of standard chemotherapy) patients with a 2-year progression-free survival rate (PFS) of 40%, we observed high HLA-G protein expression within the tumor microenvironment with low expression on Hodgkin and Reed-Sternberg (HRS) cells. Conversely, PET-2 negative patients with a PFS of 86% had higher HLA-G protein expression levels on HRS cells compared to the microenvironment. Lower expression on HRS cells was significantly associated with the HLA-G 14-bp ins/ins genotype.

These preliminary data suggest that the immunohistochemical pattern of HLA-G protein expression may represent a useful tool for a tailored therapy in patients with cHL, based on the modulation of HLA-G expression in relation to achievement of negative PET-2.

The favorable role of homozygosity for killer immunoglobulin-like receptor (KIR) A haplotype in patients with advanced-stage classic Hodgkin lymphoma

BACKGROUND

Interim positron emission tomography after 2 cycles of ABVD (iPET-2) is a good predictor of outcome in advanced-stage classic Hodgkin lymphoma. So far, there are no other prognostic biomarkers capable of identifying chemotherapy refractory patients with comparable accuracy. Despite the considerable amount of evidence suggesting that antitumor immune surveillance is downregulated in classic Hodgkin lymphoma (cHL), few data exist on the impairment of natural killer cell function and the role of their killer immunoglobulin-like receptors (KIRs).

METHODS

We investigated KIR gene frequencies, KIR haplotypes, and KIR-ligand combinations in a cohort of 135 patients with advanced-stage classic Hodgkin lymphoma and 221 healthy controls. We furthermore evaluated the correlation of KIR genes and KIR haplotypes with the achievement of negative iPET-2.

RESULTS

In the cohort of patients, the 5-year overall survival and progression-free survival were 93.6 and 79%, respectively. Homozygosity for KIR A haplotype and the HLA-C1 KIR ligand (KIR-AA/C1C1) was significantly higher in healthy controls (15.7 vs. 4.8%, p = 0.001). The KIR-AA genotype resulted to have a significant predictive power for achieving iPET-2 negativity (p = 0.039).

CONCLUSIONS

Homozygosity for KIR A haplotype offers protection against classic Hodgkin lymphoma. The association found for the KIR-AA genotype and achievement of negative iPET-2 suggests that KIR-AA could be used in clinical practice to enhance the chemosensitivity predictive power of iPET-2. Our results point to the possibility of adapting treatment strategies based on the combination of KIR biomarkers and PET scan.

The distribution of KIR-HLA functional blocks is different from north to south of Italy

The killer cell immunoglobulin-like receptor (KIR)-human leukocyte antigen (HLA) interaction represents an example of genetic epistasis, where the concomitant presence of specific genes or alleles encoding receptor-ligand units is necessary for the activity of natural killer (NK) cells. Although KIR and HLA genes segregate independently, they co-evolved under environmental pressures to maintain particular KIR-HLA functional blocks for species survival. We investigated, in 270 Italian healthy individuals, the distribution of KIR and HLA polymorphisms in three climatic areas (from cold north to warm south), to verify their possible geographical stratification. We analyzed the presence of 13 KIR genes and genotyped KIR ligands belonging to HLA class I: HLA-C, HLA-B and HLA-A. We did not observe any genetic stratification for KIR genes and HLA-C ligands in Italy. By contrast, in a north-to-south direction, we found a decreasing trend for the HLA-A3 and HLA-A11 ligands (P = 0.012) and an increasing trend for the HLA-B ligands carrying the Bw4 epitope (P = 0.0003) and the Bw4 Ile80 epitope (P = 0.0005). The HLA-A and HLA-B KIR ligands were in negative linkage disequilibrium (correlation coefficient -0.1211), possibly as a consequence of their similar function in inhibiting NK cells. The distribution of the KIR-HLA functional blocks was different along Italy, as we observed a north-to-south ascending trend for KIR3DL1, when coupled with HLA-B Bw4 ligands (P = 0.0067) and with HLA-B Bw4 Ile80 (P = 0.0027), and a descending trend for KIR3DL2 when coupled with HLA-A3 and HLA-A11 ligands (P = 0.0044). Overall, people from South Italy preferentially use the KIR3DL1-HLA-B Bw4 functional unit, while those from the North Italy equally use both the KIR3DL2-HLA-A3/A11 and the KIR3DL1-HLA-B Bw4 functional units to fight infections. Thus, only KIR3DL receptors, which exert the unique role of microbial sensors through the specific D0 domain, and their cognate HLA-A and HLA-B ligands are selectively pressured in Italy according to geographical north-to-south distribution.

Absence of activating killer immunoglobulin-like receptor genes combined with hepatitis C viral genotype is predictive of hepatocellular carcinoma

Killer immunoglobulin-like receptors and their human leukocyte antigen class I ligands have a critical role in natural killer cell response to viral pathogens and tumors. To investigate whether killer immunoglobulin-like receptor genes could influence the chronic course of hepatitis C virus infection and/or progression to hepatocellular carcinoma we retrospectively analyzed a cohort of 228 patients transplanted for hepatitis C virus-induced cirrhotic end stage liver disease, combined or not with hepatocellular carcinoma. We found that patients completely lacking activating killer immunoglobulin-like receptor genes had a high risk of developing hepatocellular carcinoma. Hepatitis C viral genotype and viral load are other risk factors that can influence the course of chronic hepatitis C virus infection. In our study, the risk conferred by hepatitis C viral genotypes was enhanced in patients lacking activating killer immunoglobulin-like receptors. These results point to an important role for activating killer immunoglobulin-like receptors in the control of hepatitis C virus infection and progression to hepatocellular carcinoma. In clinical practice, assessment of killer immunoglobulin-like receptor and hepatitis C viral genotype combinations should allow for more accurate monitoring of patients with chronic hepatitis C virus infection.

Homozygosity for killer immunoglobin-like receptor haplotype A predicts complete molecular response to treatment with tyrosine kinase inhibitors in chronic myeloid leukemia patients

Several recent reports suggest a possible role for killer immunoglobulin-like receptors (KIR) in the onset of chronic myeloid leukemia (CML) and response to therapy with tyrosine kinase inhibitors (TKIs). To explore this hypothesis, we studied KIRs and their human leukocyte antigen class I ligands in 59 consecutive patients with chronic-phase CML (mean age, 53 years; range, 23-81 years) and a group of 121 healthy control participants belonging to the same ethnic group as the patients. The 2-year cumulative incidence of complete molecular response, obtained after a median of 27 months (range, 4-52 months), was 51.2%. An increased frequency of the activating receptor KIR2DS1 (pm = 0.05) and a reduced frequency of the KIR-ligand combination KIR2DS2/2DL2 absent/C1 present (pm = 0.001) were significantly associated with CML. Moreover, KIR repertoires in patients appeared to influence response to TKI therapy. Homozygosity for KIR haplotype A (pm = 0.01), a decreased frequency of the inhibitory KIR gene KIR2DL2 (pm = 0.02), and low numbers of inhibitory KIR genes (pm = 0.05) were all significantly associated with achievement of complete molecular remission. These data suggest that a decrease in properly stimulated and activated NK cells might contribute to the occurrence of CML and indicate homozygosity for KIR haplotype A as a promising immunogenetic marker of complete molecular response that could help clinicians decide whether to withdraw treatment in patients with CML.

A unique MSH2 exon 8 deletion accounts for a major portion of all mismatch repair gene mutations in Lynch syndrome families of Sardinian origin

Lynch syndrome is an autosomal-dominant hereditary condition predisposing to the development of specific cancers, because of germline mutations in the DNA-mismatch repair (MMR) genes. Large genomic deletions represent a significant fraction of germline mutations, particularly among the MSH2 gene, in which they account for 20% of the mutational spectrum. In this study we analyzed 13 Italian families carrying MSH2 exon 8 deletions, 10 of which of ascertained Sardinian origin. The overrepresentation of Sardinians was unexpected, as families from Sardinia account for a small quota of MMR genes mutation tests performed in our laboratory. The hypothesis that such a result is owing to founder effects in Sardinia was tested by breakpoint junctions sequencing and haplotype analyses. Overall, five different exon eight deletions were identified, two of which recurrent in families, all apparently unrelated, of Sardinian origin (one in eight families, one in two families). The c.1277-1180_1386+2226del3516insCATTCTCTTTGAAAA deletion shares the same haplotype between all families and appears so far restricted to the population of South-West Sardinia, showing the typical features of a founder effect. The three non-Sardinian families showed three different breakpoint junctions and haplotypes, suggesting independent mutational events. This work has useful implications in genetic testing for Lynch syndrome. We developed a quick test for each of the identified deletions: this can be particularly useful in families of Sardinian origin, in which MSH2 exon 8 deletions may represent 50% of the overall mutational spectrum of the four MMR genes causing Lynch syndrome.

The 312N variant of the luteinizing hormone/choriogonadotropin receptor gene (LHCGR) confers up to 2·7-fold increased risk of polycystic ovary syndrome in a Sardinian population

OBJECTIVE

Polycystic ovary syndrome (PCOS) is a frequent condition, affecting about 15% of women of reproductive age. Because of its familial occurrence, a multifactorial model of susceptibility, including both genetic and environmental factors, has been proposed. However, the identification of genetic factors has been elusive.

DESIGN

Case-control study aimed at evaluating possible associations between functionally relevant variants of the luteinizing hormone/choriogonadotrophin receptor gene (LHCGR) and PCOS phenotype.

PATIENTS

A total of 198 PCOS and 187 non-PCOS women, aged 14-35 years, of Sardinian origin, were referred to the outpatient clinic of the Department of Obstetrics and Gynaecology of the University of Cagliari (Sardinia). PCOS diagnosis was based on the Rotterdam criteria.

MEASUREMENTS

We determined the genotype of ins18LQ, S291N and S312N variants at the LHCGR locus. Genotype was related to the presence or absence of PCOS and to several clinical and biochemical characteristics.

RESULTS

The presence of at least one 312N allele was strongly associated with PCOS risk (OR, 2·04; 95% CI, 1·32-3·14; χ(2) , 10·47; P = 0·001). 312N homozygosity was associated with a further risk increase (OR, 2·73; 95% CI, 1·25-5·95; χ(2) , 6·65; P = 0·01). The number of ins18LQ alleles was associated with LH serum levels in controls (χ(2) , 8·04, P = 0·017).

CONCLUSIONS

For the first time, we have identified a genetic variant that is strongly associated with PCOS in an isolated population. These results, if confirmed in other cohorts, may provide the opportunity to test the S312N genotype at the LHCGR locus in fertile women to assess the risk of PCOS. The avoidance of triggering factors like weight increase may improve the reproductive outcome of potentially at-risk subjects.

Genetics of Behçet's disease in Sardinia: two distinct extended HLA haplotypes harbour the B*51 allele in the normal population and in patients

OBJECTIVES

To define the contribution of HLA genes and extended HLA haplotypes to the susceptibility to Behçet's disease (BD) in Sardinia.

METHODS

Forty-five unrelated Sardinian patients with BD, diagnosed according to the ISG criteria, 45 HLA-B*51 positive and 185 unselected healthy controls were enrolled in the study. DNA samples were typed for HLA class I and class II alleles and genotyped for microsatellites (MICA-TM) and single-nucleotide polymorphisms (rs1264457 HLA-E; rs2281820 motilin; rs1799724 at -857, rs361525 at -238 TNF-alpha) spanning the HLA region.

RESULTS

HLA-B*5101 was confirmed as conferring susceptibility to BD (pc=0.0042; OR=4.4; 95% CI=2.0 to 9.6). It is noteworthy that in Sardinia this allele was found more frequently within a haplotype (HLA-A2; -Cw2; -B*5101; -DRB1*11; -DQA1*05; - DQB1*03) that reached its highest frequency in patients with BD. Linkage disequilibrium analysis showed the existence of an additional B*51 haplotype (HLA-A2; -Cw2; -B*5101; -DRB1*04; -DQA1*03; -DQB1*03) not associated with susceptibility to the disease.

CONCLUSIONS

In Sardinia, the BD-associated HLA-B*5101 allele is inherited as part of two distinctive haplotypes differently distributed in patients and controls. These findings can be interpreted as suggestive of the presence of additional genes within the MHC region conferring susceptibility to BD. The hypothesis that an environmental pressure could have contributed to the preservation of the BD-associated HLA haplotype in Sardinia is also discussed.

Susceptibility to ankylosing spondylitis but not disease outcome is influenced by the level of HLA-B27 expression, which shows moderate variability over time

OBJECTIVE

Previous reports have highlighted the relevance of HLA-B27 expression in the pathogenesis of ankylosing spondylitis (AS). The aim of the current study was to estimate the level of HLA-B27 expression on the cell surface of ex vivo monocytes and lymphocytes by a quantitative method and to correlate this with AS disease susceptibility, disease clinical indexes, and the occurrence of acute anterior uveitis (AAU).

METHOD

We recruited 32 B27-positive patients with AS and 32 B27-positive healthy normal controls (NCs) for evaluation at different time points. The expression of HLA-B27 molecules was quantified by flow cytometry on ex vivo peripheral blood mononuclear cells (PBMCs). Patients were also evaluated by scores on the Bath AS disease activity (BASDAI), functional (BASFI), and metrology (BASMI) indexes.

RESULTS

The expression of HLA-B27 molecules was significantly higher in patients with AS than in B27-matched controls in the case of both monocytes [219K (IQR 174K-308K) vs. 137K (IQR 96K-170K), p < 0.0001] and lymphocytes [82K (IQR 58K-118K) vs. 54K (IQR 44K-61K), p < 0.0001]; AS only vs. AS with AAU: p = 0.744 in monocytes and p = 0.701 in lymphocytes. Comparisons with metrology and functional indexes were also not significant (BASMI: r = 0.05, p = 0.77; BASFI: r = -0.09, p = 0.67). The overexpression of HLA-B27 molecules was stable after 1 week of follow-up. At 3 years follow-up, the variability was moderate and did not correlate with variations in disease activity (BASDAI: r = -0.01, p = 0.92 ns).

CONCLUSIONS

The level of HLA-B27 expression in PBMCs correlates with the susceptibility to AS but not with the disease outcome, nor with the occurrence of extra-articular manifestations such as AAU.

Interactions between killer immunoglobulin-like receptors and their human leucocyte antigen Class I ligands influence the outcome of unrelated haematopoietic stem cell transplantation for thalassaemia: a novel predictive algorithm

In a study conducted on 114 patients undergoing unrelated donor haematopoietic stem cell transplantation (HSCT) for thalassaemia, we observed that the lack of activating killer immunoglobulin-like receptors (KIRs) on donor natural killer (NK) cells significantly increased the risk of graft-versus-host disease (GvHD) [hazard risk (HR) 4.2, 95% confidence interval (CI) 1.7-10.1, P = 0.002] and transplantation-related mortality (HR 4.7, 95% CI 1.6-14.2, P = 0.01). The risk of GvHD furthermore increased when recipients heterozygous for HLA-C KIR ligand groups (C1/C2) were transplanted from donors completely lacking activating KIRs (HR 6.1, 95% CI 1.9-19.2, P = 0.002). We also found that the risk of rejection was highest when the recipient was homozygous for the C2 HLA-KIR ligand group and the donor carried two or more activating KIRs (HR 6.8, 95% CI 1.9-24.4, P = 0.005). By interpolating the number of donor activating KIRs with recipient HLA-C KIR ligands, we created an algorithm capable of stratifying patients according to the immunogenetic risk of complications following unrelated HSCT. In clinical practice, this predictive tool could serve as an important supplement to clinical judgement and decision-making.

Association between different morphological types and abnormal karyotypes in early pregnancy loss

OBJECTIVES

To identify the abnormal transvaginal ultrasound (TVS) findings typical of aneuploidic pregnancies that end with early pregnancy loss (EPL).

METHODS

This was a prospective clinical trial over a 2½-year period from January 2004 to June 2006 at the University Hospital of Cagliari, Italy. One hundred and fifty-six singleton pregnancies with EPL were evaluated by TVS, both before and at the moment of EPL diagnosis. Fetal karyotyping was performed on products of conception using microsatellite analysis to exclude maternal contamination in 46,XX cases. The proportions of abnormal karyotypes were compared among different groups of EPLs characterized by different morphological features.

RESULTS

Six morphological types were identified in EPLs, one normal and five abnormal (small gestational sac, small embryo/fetus, early symmetrical arrested growth, enlarged yolk sac and empty sac). The highest rate of chromosomal abnormalities was observed in the early symmetrical arrested growth group (100%), followed by small embryo/fetus (94.1%), enlarged yolk sac (93.3%) and empty sac (72.2%) groups. The majority of cases of trisomy 22 (92.3%) were in the enlarged yolk sac group and the majority of cases with a 45,X karyotype were in the small embryo/fetus group (77.8%).

CONCLUSIONS

There is an association in EPLs between some abnormal karyotypes and some morphological types. The demonstration by TVS of abnormalities in the development of early pregnancy structures could be helpful for predicting aneuploidy in EPLs.

The conundrum of HLA-DRB1*14:01/*14:54 and HLA-DRB3*02:01/*02:02 mismatches in unrelated hematopoietic SCT

Uncertainty still exists on the role of polymorphisms outside the HLA-DRB1 binding site or inside the HLA-DRB3 binding groove in unrelated hematopoietic SCT (HSCT). The ideal model to solve the conundrum consists of the transplants mismatched for HLA-DRB1*14:01/*14:54 and/or for HLA-DRB3*02:01/*02:02. A task force was set up in Italy to recruit transplanted pairs defined as HLA-DRB1*14:01 before 2006, the year crucial for the proper definition of the HLA-DRB1*14:54 allele in molecular biology. Out of 2723 unrelated pairs, 189 transplanted in Italy from 1995 to 2006 were HLA-DRB1*14:01 positive; 103/189 pairs with good historical DNA were retyped for HLA-DRB1*14 and HLA-DRB3 at-high resolution level; 31/103 pairs had HLA-DRB1*14 and/or HLA-DRB3 mismatched; 99/103, having complete clinical data, underwent statistical analysis for OS, TRM, disease-free survival and acute and chronic GvHD. No significant involvement of HLA-DRB1*14:01/*14:54 or HLA-DRB3*02:01/*02:02 mismatches was found, either alone or combined. Our findings suggest that disparities at exon 3 of the HLA-DRB1 gene seem unlikely to influence the outcome after HSCT. The same may be envisaged for HLA-DRB3(*)02:01 and (*)02:02 alleles which, although differing in the Ag binding site, seem unable to modulate an appreciable immune response in an HSCT setting.

HLA-E gene polymorphism associates with ankylosing spondylitis in Sardinia

INTRODUCTION

Ankylosing spondylitis (AS) is a severe, chronic inflammatory disease strongly associated with HLA-B27. The presence of additional HLA risk factors has been suggested by several studies. The aim of the current study is to assess the occurrence of an additional HLA susceptibility locus in the region between HLA-E and HLA-C in the Sardinian population.

METHODS

200 random controls, 120 patients with AS and 175 HLA-B27 positive controls were genotyped for six single nucleotide polymorphisms (SNPs) spanning the HLA region between HLA-E and HLA-C loci previously shown to harbour an additional susceptibility locus for AS. Allele, genotype and haplotype frequencies were compared.

RESULTS

The data confirm our previous finding of a significant increase in patients with AS of allele A at SNP rs1264457 encoding for an Arg at the functional HLA-E polymorphism (Arg128/Gly128). This was due to a remarkable increase in the frequency of genotype A/A in patients vs HLA-B27-matched controls (51% vs 29%; P for trend: 5 x 10-5). Genotype distribution of three other SNPs mapping in genes (GNL1, PRR3 and ABCF-1) close to HLA-E and showing high LD with it, was also significantly skewed. Accordingly, haplotype distribution was also remarkably different. The frequency of the haplotype AAGA, is 42% in random controls, increases to 53% in the HLA-B27-positive controls, and reaches 68% in patients with AS (P values: 2 x 10-11 vs random and 3 x 10-4 vs HLA-B27 controls).

CONCLUSIONS

There is a strong association between the presence of a haplotype in genes mapping between HLA-E and HLA-C and AS due to an increase of homozygous markers in patients. The strongest association however, is with the HLA-E functional polymorphism rs1264457. Since HLA-E is the ligand for the NKG2A receptor, these data point to the natural killer (NK) activity as possible player in the pathogenesis of AS.

Identification of a new HLA DRB1 allele (HLA-DRB1*1167) in a potential hematopoietic stem cell donor from Iraqi Kurdistan

High-resolution polymerase chain reaction sequence-specific primer typing and sequence-based typing of the human leukocyte antigen (HLA) gene DRB1 in a potential hematopoietic stem cell donor of Kurdish ethnicity revealed a new allelic variant of HLA-DRB1*11. The sequence was named DRB1*1167, and comparison with previously described DRB1 alleles demonstrated a mixed pattern shared with some DRB1*08 alleles.

Association of MICA alleles with psoriatic arthritis and its clinical forms. A multicenter Italian study

OBJECTIVE

Analysis of the association between psoriatic arthritis (PsA) clinical forms and MICA gene transmembrane polymorphisms.

METHODS

Patients were classified as having peripheral asymmetric oligoarthritis (AO), peripheral symmetric poly-arthritis (PA) and spondylitis (SP), or disease combinations (PA/SP, OA/SP). Two hundred and twenty-six patients with PsA were typed for MICA exon 5 microsatellite (TM) by heteroduplex analysis and compared with 225 normal controls.

RESULTS

MICA-TM microsatellite typing revealed that, among the different clinical forms of PsA, only the combined PA/SP subset shows a significant positive association with MICA-A9 and a lower frequency of MICA-A4, A5 genotype in PsA patients with a decrease, only in the PA/SP cohort, of all MICA-A5 combinations except MICA-A5, -A9.

CONCLUSION

These results suggest a role for genes within the HLA region in the pathogenesis of PsA, and reinforce the idea that the different forms of PsA may have heterogeneous genetic basis.

HLA-G gene polymorphism in human placentas: possible association of G*0106 allele with preeclampsia and miscarriage

Definite causes for several pathologies of pregnancy remain unknown. In light of several recent studies, however, diminished or aberrant HLA-G expression may be associated with certain complication of pregnancy and be linked to HLA-G polymorphism. We analyzed DNA from 60 normal placentas (controls), 140 placentas from miscarriage, 36 placentas from preeclampsia, 76 placentas from fetal hypotrophy, and 34 placentas with hypoxia for variations in coding regions (allelic groups G*0101 to G*0107) and the 14-bp deletion/insertion into the 3'-untranslated region. No statistically significant differences were observed in the distribution of allelic group between pathological placentas and controls with the exception of G*0106 allele frequency in preeclamptic compared with control placentas (21.2% and 6.6%, respectively). A greater frequency of this allele also was observed in the two subgroups of miscarriage and hypoxia compared with that in controls. In addition, presence of the 14-bp sequence was prominent in preeclampsia compared with controls (60.8% vs. 35%, respectively), and homozygotes with deletion were not detected in the pathology. The results suggest that the G*0106 allele, which is coupled with the presence of the 14-bp sequence, contributes and/or is a relevant marker in some specific complications of pregnancy, especially preeclampsia.

The human leucocyte antigen-G 14-basepair polymorphism correlates with graft-versus-host disease in unrelated bone marrow transplantation for thalassaemia

The presence of the 14-bp insertion polymorphism of the human leucocyte antigen (HLA)-G gene (HLA-G) promotes immune tolerance through increased synthesis of HLA-G molecules. We investigated this polymorphism in a large cohort of 53 thalassaemia patients transplanted from an unrelated donor. Sixteen patients (30.2%) homozygous for the 14-bp deletion had a higher risk of developing acute graft-versus-host disease (aGvHD) than patients homozygous for the 14-bp insertion (-14-bp/-14-bp vs +14-bp/+14-bp: Relative Risk = 15.0; 95% confidence interval 1.59-141.24; P = 0.008). Therefore, the 14-bp polymorphism could be an important predictive factor for aGvHD following bone marrow transplantation.

RET proto-oncogene in Sardinia: V804M is the most frequent mutation and may be associated with FMTC/MEN-2A phenotype

OBJECTIVE

Genetic screening of RET proto-oncogene is a powerful tool for the early identification of familial cases of medullary thyroid carcinoma (MTC), comprising isolated familial thyroid medullary carcinoma (FMTC) and multiple endocrine neoplasia syndromes 2A (MEN-2A) and 2B (MEN-2B). We report the results obtained by RET mutation analysis of subjects living in Sardinia, an Italian island whose inhabitants display a peculiar genetic background due to geographic isolation and low immigration rate for several centuries.

DESIGN

Retrospective study reporting data on 67 patients referred during the last 5 years for RET analysis because affected by MTC or first degree relatives of MTC patients.

MAIN OUTCOME

Only three mutations were identified affecting codons 620 (exon 10), 634 (exon 11), and 804 (exon 14); surprisingly, the most prevalent mutation found was V804M (overall prevalence: 59%). This finding is quite different from previous studies carried out in other Caucasian and non-Caucasian populations, in which the frequency of the V804M mutation is consistently reported less than 5%. The phenotype associated to V804M mutation was mostly FMTC (16/17 cases = 94.1%), but in one case (5.9%) primary hyperparathyroidism was found, suggesting a MEN-2A.

CONCLUSIONS

These results underline the importance of the genetic background in the distribution of RET mutations and should be taken into consideration when performing genetic evaluation of MTC patients.

Distribution of killer cell immunoglobulin-like receptors genes in the Italian Caucasian population

Background

Killer cell immunoglobulin-like receptors (KIRs) are a family of inhibitory and activatory receptors that are expressed by most natural killer (NK) cells. The KIR gene family is polymorphic: genomic diversity is achieved through differences in gene content and allelic polymorphism. The number of KIR loci has been reported to vary among individuals, resulting in different KIR haplotypes. In this study we report the genotypic structure of KIRs in 217 unrelated healthy Italian individuals from 22 immunogenetics laboratories, located in the northern, central and southern regions of Italy.

Methods

Two hundred and seventeen DNA samples were studied by a low resolution PCR-SSP kit designed to identify all KIR genes.

Results

All 17 KIR genes were observed in the population with different frequencies than other Caucasian and non-Caucasian populations; framework genes KIR3DL3, KIR3DP1, KIR2DL4 and KIR3DL2 were present in all individuals. Sixty-five different profiles were found in this Italian population study. Haplotype A remains the most prevalent and genotype 1, with a frequency of 28.5%, is the most commonly observed in the Italian population.

Conclusion

The Italian Caucasian population shows polymorphism of the KIR gene family like other Caucasian and non-Caucasian populations. Although 64 genotypes have been observed, genotype 1 remains the most frequent as already observed in other populations. Such knowledge of the KIR gene distribution in populations is very useful in the study of associations with diseases and in selection of donors for haploidentical bone marrow transplantation.

HLA-dependent hypersensitivity to nevirapine in Sardinian HIV patients

BACKGROUND

Hypersensitivity reaction to nevirapine, which in some cases can be fatal, shows a higher prevalence in Sardinia in comparison with other Italian regions.

OBJECTIVE

This study demonstrates that hypersensitive reaction to nevirapine in Sardinian HIV-infected patients is associated with the HLA Cw8-B14 haplotype. These two HLA class I antigens are in strong linkage disequilibrium in the Sardinian population.

METHODS

Forty-nine Sardinian HIV-positive patients treated with nevirapine were studied. Thirteen (26%), developed a hypersensitive reaction thus requiring the drug to be discontinued. HLA class I and II molecular typing was performed in both nevirapine-hypersensitive and nevirapine-tolerant patients. To avoid biased representation of the allele frequencies in the two groups of treated patients, molecular typing was also performed in 82 HIV-positive patients who had not been treated with nevirapine.

RESULTS

Considerable overlap was observed for the clinical, immunological and demographic characteristics of the 13 hypersensitive patients and 36 tolerant patients. Clinical parameters included viral load, status of HIV infection, CD4 and CD8 cell counts, hepatitis C virus/hepatitis B virus co-infections. Forty-six percent (6/13) of the nevirapine-hypersensitive subjects had the HLA-Cw8 and HLA-B14(65) antigens compared with 5% (2/36) of the nevirapine-tolerant group (P = 0.004; Pc = 0.05).

CONCLUSION

In agreement with other recent reports, the utility of HLA typing in HIV patients to identify genetic factors that may confer susceptibility to drug-induced hypersensitive reaction was confirmed. A careful choice of antiretroviral therapy in susceptible individuals should significantly reduce the risk of severe hypersensitive reaction.

Association of HLA-DRB3*0202 and serum IgG antibodies to Chlamydia pneumoniae with essential hypertension in a highly homogeneous population from Majorca (Balearic Islands, Spain)

Separate studies investigating the relationship of essential hypertension (EH) with the HLA system and with Chlamydia pneumoniae (C. pneumoniae) infection have given conflicting results. Our aim was to clarify these relationships and determine whether the HLA system and C. pneumoniae infection interact with respect to the risk for EH. An association study (110 essential hypertensives and 107 controls) was conducted in a highly homogeneous population in the Balearic Island of Majorca (Spain). Molecular typing of HLA-B and HLA-DRB and quantification of serum levels of IgG antibodies to C. pneumoniae (sIgGa-Cp) were determined. Student's t-test, chi(2)-statistics, logistic regression analysis, and general linear model ANOVA were used for statistical analysis. The results showed that EH was related with HLA-DRB3*0202 in the whole study population, and with levels of sIgGa-Cp>63.5 BU/ml in the group of individuals with sIgGa-Cp>30 BU/ml (OR (95% CI) adjusted for obesity, familial history of EH and diabetes=2.06 (1.07-3.97), P=0.03, and =4.60 (1.06-19.90), P=0.04, respectively). The association between EH and sIgGa-Cp was observed in the DRB3*0202(+) individuals, but not in the DRB3*0202(-) subgroup (OR (95% CI)=11.14 (1.92-64.54), P=0.004, and =0.98 (0.22-4.43), P=0.64, respectively (P of the Mantel-Haenszel test for homogeneity of OR=0.06)). In our population, EH was positively associated with HLA-DRB3*0202 and with high levels of sIgGa-Cp. Moreover, a significant interaction of DRB3*0202 on the effect of sIgGa-Cp was observed, as the association of EH with these antibodies depended on the presence of DRB*0202.

Graft rejection after unrelated donor hematopoietic stem cell transplantation for thalassemia is associated with nonpermissive HLA-DPB1 disparity in host-versus-graft direction

The success of allogeneic hematopoietic stem cell transplantation (HSCT) from matched unrelated donors (UDs) for beta-thalassemia may be hampered by the occurrence of graft rejection. Here, we show that the rate of this complication can be reduced by selecting 5-loci HLA-matched donors without nonpermissive mismatches at HLA-DPB1, defined according to an algorithm previously described and based on principles of central T-cell tolerance. Seventy-two consecutive patients and their UDs, prospectively selected for matching at the allelic level for HLA-A, -B, -C, -DRB, and -DQB1 loci, were enrolled in the analysis. These pairs were either DPB1 matched/permissively mismatched (n = 45, control group) or had at least one nonpermissive DPB1 mismatch in the host-versus-graft (HvG; n = 17) or in the graft-versus-host (GvH; n = 10) direction. In multivariate analysis, the risk of rejection was significantly increased in the group with HvG disparity (RR = 7.42; 95% CI = 1.29-42.68; P = .02) as compared to the control group. A lower, statistically significant, probability of thalassemia-free survival was found in patients belonging to the HvG group as compared to controls (RR = 5.15; 95% CI = 1.58-16.82; P = .01). These data suggest that in patients with thalassemia, the incidence of graft failure after HSCT may be reduced by appropriate selection of UDs, with such selection taking into account the functional rules of immunogenetics.

Classic Kaposi's sarcoma in Sardinia: HLA positive and negative associations

BACKGROUND

The incidence of classic Kaposi's sarcoma (CKS) in northern Sardinia is one of the highest in the world.

METHODS

Sixty-two patients with CKS were typed for class I and class II antigens. All patients had been born and were living in northern Sardinia.

RESULTS

In the Sardinian patients, we observed a positive CKS association with Cw7, DRB1*1104, DRB1*1302, DQA1*0302, and DQB1*0604, and a negative CKS association with A30, B58, Cw5, DRB1*1601, and DQB1*0502.

CONCLUSIONS

The strong positive CKS association with DRB1*1104 and DQB1*0604 and negative association with B58 are particularly significant and further support the notion of a genetic predisposition to CKS.

Systemic lupus erythematosus in Europe at the change of the millennium: lessons from the "Euro-Lupus Project"

The "Euro-Lupus Cohort" is composed by 1000 patients with systemic lupus erythematosus (SLE) that have been followed prospectively since 1991. These patients have been gathered by a European consortium--the "Euro-Lupus Project Group". This consortium was originated as part of the network promoted by the "European Working Party on SLE", a working group created in 1990 in order to promote research in Europe on the different problems related to this disease. The "Euro-Lupus Cohort" provides an updated information on the SLE morbidity and mortality characteristics in the present decade as well as defines several clinical and immunological prognostic factors.

Identification of a new allele, HLA-DRB1*1366*

High-resolution polymerase chain reaction sequence-specific primer typing of the human leucocyte antigen (HLA)-DRB1 gene of an Italian patient candidate for bone marrow transplantation revealed a new allelic variant of HLA-DRB1*13. The sequence was named DRB1*1366, and comparison with previously described DRB1 alleles demonstrated the two closely related sequences were HLA-DRB1*1330 and HLA-DRB1*130302.

HPRTSardinia: a new point mutation causing HPRT deficiency without Lesch-Nyhan disease

Hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency always causing hyperuricemia presents various degrees of neurological manifestations, the most severe which is Lesch-Nyhan syndrome. The HPRT gene is situated in the region Xq26-q27.2 and consists of 9 exons. At least 300 different mutations at different sites in the HPRT coding region from exon 1 to exon 9 have been identified. A new mutation in the HPRT gene has been determined in one patient with complete deficiency of erythrocyte activity, with hyperuricemia and gout but without Lesch-Nyhan disease. Analysis of cultured fibroblasts revealed minimal residual HPRT activity mainly when guanine was the substrate. Genomic DNA sequencing demonstrated patient's mother heterozygosity for the mutation and no mutation in her brother. The mutation consists in a C-->T transversion at cDNA base 463 (C463T) in exon 6, resulting in proline to serine substitution at codon 155 (P155S). This mutation had not been reported previously and has been designated HPRT(Sardinia). The mutation identified in this patient allows some expression of functional enzyme in nucleated cells such as fibroblasts, indicating that such cell type may add further information to conventional blood analysis. A multicentre survey gathering patients with variant neurological forms could contribute to understand the pathophysiology of the neurobehavioral symptoms of HPRT deficiency.

SOD1 mutations in amyotrophic lateral sclerosis

Amyotrophic Lateral Sclerosis (ALS), the most common form among motoneuron diseases, is characterized by a progressive neurodegenerative process involving motor neurons in the motor cortex, brain stem and spinal cord. Sporadic (SALS) accounts for the majority of patients but in about 10% of ALS cases the disease is inherited (FALS), usually as an autosomal dominant trait. In the present study we show the results of a referred based multicenter study on the distribution of SOD1 gene mutations in the largest cohort of Italian ALS patients described so far. Two hundred and sixty-four patients (39 FALS and 225 SALS) of Italian origin were studied. In 7 out of 39 FALS patients we found the following SOD1 gene mutations: i) a new G12R missense mutation in exon 1, found in a patient with a slowly progressive disease course; ii) the G41S mutation, in four unrelated patients with rapidly progressive course complicated with cognitive decline in two of them; iii) the L114F mutation, in a patient with a slowly progressive phenotype; iv) the D90A mutation, in a heterozygous patient with atypical phenotype. In addition, in one SALS patient a previously reported synonymous variant S59S was identified. In 17 (3 FALS and 14 SALS) out of 264 patients (6.4 %) the polymorphism A-->C at position 34 of intron 3 (IVS3: + 34 A-->C) was found, and in one FALS patient a novel variant IVS3 + 62 T-->C was identified. The frequency of SOD1 gene mutations (17.9 %) in FALS cases was comparable with that found in other surveys with a similar sample size of ALS cases. No SOD1 gene mutations have been identified in SALS cases. Within FALS cases, The most frequent mutation was the G41S identified in four FALS.

Mapping of the major psoriasis-susceptibility locus (PSORS1) in a 70-Kb interval around the corneodesmosin gene (CDSN)

Numerous putative susceptibility loci have been described for psoriasis. Among the loci confirmed in the literature, PSORS1 (the major histocompatibility complex at 6p21.3) has the strongest effect. Recent studies have highlighted a 200-kb candidate region. However, this region has not been well delimited, mainly because of the strong linkage equilibrium among the associated alleles. To finely map PSORS1, we set up a study using 17 polymorphic markers in a 525-kb interval around the human leucocyte antigen C locus (HLA-C). The results uncovered five loci with alleles strongly associated with psoriasis (Sidak-corrected P [P(c)] values from 1.8 x 10(-7) to .003), all structured in a psoriasis-susceptibility haplotype (PSH). Subsequent analysis of extended haplotypes showed that the PSH was not only present on the traditional psoriasis-susceptibility extended haplotypes (HLA-Cw6-B57, HLA-Cw6-B37, and HLA-Cw6-B13) but also on a haplotype of Sardinian origin (HLA-Cw7-B58) found to be associated with psoriasis (Pc=.0009) because of an ancestral recombination with one of the susceptibility haplotypes carrying the HLA-Cw6 allele. Comparisons of the regions identical by descent among associated and nonassociated haplotypes highlighted a minimum region of 70 kb not recombinant with PSORS1, around the corneodesmosin (CDSN) gene.

A new germline RET mutation apparently devoid of transforming activity serendipitously discovered in a patient with atrophic autoimmune thyroiditis and primary ovarian failure

Gain-of-function RET mutations are responsible for multiple endocrine neoplasia syndromes (MEN) 2A and 2B and familial medullary thyroid carcinoma (FMTC), whereas loss-of-function mutations are found in Hirschsprung disease. We report a new RET point mutation [R694Q (CGG-->CAG)], serendipitously found in a 23-yr-old woman with hypothyroidism due to atrophic Hashimoto's thyroiditis and primary ovarian failure, without altered calcitonin secretion. Familial history and clinical and biochemical evaluation of first-degree relatives were negative for FMTC, MEN 2A and 2B, and Hirschsprung disease. Genetic analysis showed that the mutation was inherited from the mother, who was submitted 2 yr before to thyroidectomy for goitrous Hashimoto's thyroiditis. Histological revision and immunohistochemical studies documented normal C cell number and morphology. We cloned the mutation in an expression vector encoding a full-length RET protein. The construct was transiently expressed in 293T cells in parallel with a wild-type RET and a C634R MEN 2A-associated RET mutant. Proteins were harvested from transfected cells, and tyrosine phosphorylation levels were assayed. The mutation did not exert significant potentiating effects on RET kinase. A focus assay was also performed on NIH3T3 fibroblasts; the mutant did not exert significant transforming activity. In conclusion, a new RET mutation was found in two subjects without any evidence of MEN and FMTC. In keeping with clinical data, transfection studies confirmed lack of activating activity. This serendipitous discovery, apparently devoid of oncogenic potential, underscores the problems that may be encountered in genomic studies on RET.

A psoriasis vulgaris protective gene maps close to the HLA-C locus on the EH18.2-extended haplotype

We determined the molecular haplotypes of the HLA-A, HLA-C and HLA-B loci and the MHC class I-B-related (MIB) microsatellite in 179 unrelated psoriatic patients (72 familial cases) and in 120 controls. The HLA-A*3002-Cw*0501-B*1801-MIB1 haplotype showed a strong negative association with psoriasis vulgaris (PV) and in particular with familial PV, revealing the presence of a PV-protective gene. Analysis of association and linkage disequilibrium of the single alleles and the various two-three-four-locus segments of this haplotype indicated the presence of a protective gene telomeric to the HLA-C locus. This finding was confirmed in 13 informative multiplex PV families, in which at least one parent carried the EH18.2 haplotype. In two families, an affected sibling presented HLA-A/C recombination on the EH18.2 haplotype. A study of 12 polymorphic microsatellites in all members of the informative families, 145 PV patients, 120 controls and 32 EH18.2 homozygous healthy individuals demonstrated that the protection conferred by the EH18.2 haplotype lies within a 170 kb interval between the C143 and C244 loci, most probably in a 60 kb segment between the C132 and C244 loci.

A novel germline mutation of MEN 1 gene in a patient with acromegaly and multiple endocrine tumors

Germline mutations of the MEN 1 gene are responsible for multiple endocrine neoplasia type 1 (MEN 1), a dominantly inherited cancer syndrome characterized by tumors of the parathyroids, gastro-intestinal endocrine tissue, anterior pituitary and other endocrine tissues. We report on a 55-yr old woman, presenting with active acromegaly (due to GH-secreting microadenoma), associated to bilateral adrenal adenomatosis and Hürthle-cell thyroid neoplasia. No evidence of hyperparathyroidism or gastrin-secreting tumor was found. Peripheral blood genomic DNA was extracted, amplified by PCR, purified and analyzed by direct sequencing. The analysis revealed a heterozygous mutation in exon 4 of the MEN 1 gene: a G to A missense mutation at codon 229 (CGC-->CAC), which changes arginine to histidine. This mutation causes loss of the Hhal restriction site and can thus be employed for a rapid familiar screening. This case represents a newly recognized germline mutation of the MEN 1 gene.