Ethnic-specific distribution of mutations in 716 patients with congenital adrenal hyperplasia owing to 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD) occurs worldwide. The most common mutations in the CYP21A2 gene in 716 unrelated patients were analyzed and the mutations were grouped by ethnicity, as defined through self-declaration corroborated by review of pedigrees extending to two or three generations. Prevalent allelic mutations and genotypes were found to vary significantly among ethnic groups, and the predominance of the prevalent mutations and genotypes in several of these populations was significant. There are ethnic-specific mutations in the CYP21A2 gene. A large deletion is prevalent in the Anglo-Saxons; a V281L (1685 G to T) mutation is prevalent in Ashkenazi Jews; an R356W (2109 G to A) mutation is prevalent in the Croatians; an IVS2 AS -13 (A/C to G) mutation is prevalent in the Iranians and Yupik-speaking Eskimos of Western Alaska; and a Q318X (1994 C to T) mutation is prevalent in East Indians. Genotype/phenotype non-correlation was seen when at least one IVS2 AS -13 (A/C to G) mutation in the CYP21A2 gene was present.

A forward genetics screen in mice identifies recessive deafness traits and reveals that pejvakin is essential for outer hair cell function

Deafness is the most common form of sensory impairment in the human population and is frequently caused by recessive mutations. To obtain animal models for recessive forms of deafness and to identify genes that control the development and function of the auditory sense organs, we performed a forward genetics screen in mice. We identified 13 mouse lines with defects in auditory function and six lines with auditory and vestibular defects. We mapped several of the affected genetic loci and identified point mutations in four genes. Interestingly, all identified genes are expressed in mechanosensory hair cells and required for their function. One mutation maps to the pejvakin gene, which encodes a new member of the gasdermin protein family. Previous studies have described two missense mutations in the human pejvakin gene that cause nonsyndromic recessive deafness (DFNB59) by affecting the function of auditory neurons. In contrast, the pejvakin allele described here introduces a premature stop codon, causes outer hair cell defects, and leads to progressive hearing loss. We also identified a novel allele of the human pejvakin gene in an Iranian pedigree that is afflicted with progressive hearing loss. Our findings suggest that the mechanisms of pathogenesis associated with pejvakin mutations are more diverse than previously appreciated. More generally, our findings demonstrate that recessive screens in mice are powerful tools for identifying genes that control the development and function of mechanosensory hair cells and cause deafness in humans, as well as generating animal models for disease.

LRP6 mutation in a family with early coronary disease and metabolic risk factors

Coronary artery disease (CAD) is the leading cause of death worldwide and is commonly caused by a constellation of risk factors called the metabolic syndrome. We characterized a family with autosomal dominant early CAD, features of the metabolic syndrome (hyperlipidemia, hypertension, and diabetes), and osteoporosis. These traits showed genetic linkage to a short segment of chromosome 12p, in which we identified a missense mutation in LRP6, which encodes a co-receptor in the Wnt signaling pathway. The mutation, which substitutes cysteine for arginine at a highly conserved residue of an epidermal growth factor-like domain, impairs Wnt signaling in vitro. These results link a single gene defect in Wnt signaling to CAD and multiple cardiovascular risk factors.

Gender dimorphism in the DAT1 -67 T-allele homozygosity and predisposition to bipolar disorder

Linkage and association studies implicate the dopamine transporter gene (DAT1) in the etiopathophysiology of bipolar disorder. We have recently reported the association between the DAT1 core promoter -67A/T polymorphism and this disorder in a sample of Iranian patients. For the first time, these data support sex dimorphism in the homozygosity for the -67 T-allele between male and female affected cases. The present study was undertaken with a larger sample size of cases (N=240) and controls (N=213) to determine whether there is consistent difference between male and female patients and homozygosity for this allele. The results confirm and strengthen our preliminary observation that homozygosity for the T-allele is a predisposing factor in male patients, but not in females (chi2=8.825, df=1, p=0.003). Moreover, Hardy-Weinberg disequilibrium was observed in the female cases studied (chi2=12.9, df=1, p=0.0003), which may reflect the underlying biology. These findings imply gender dimorphism with respect to the DAT1 -67 alleles and susceptibility to disease.

Validation of a reverse-hybridization StripAssay for the simultaneous analysis of common α-thalassemia point mutations and deletions

BACKGROUND

alpha-Thalassemia is a worldwide disease and considered to be a major public health problem in countries within the so-called thalassemia belt. The complex genetics of alpha-thalassemias requires diagnostic methods with the capacity to screen rapidly and accurately for common causative mutations.

METHODS

We developed and validated a reverse-hybridization assay (Alpha-Globin StripAssay) for the rapid and simultaneous detection of 21 alpha-globin mutations: two single gene deletions (-alpha(3.7); -alpha(4.2)), five double gene deletions [--(MED); --(SEA); --(THAI); --(FIL); -(alpha)(20.5)], alpha alpha alpha(anti-3.7) gene triplication, two point mutations in the alpha1 gene (cd 14 G>A; Hb Adana) and 11 point mutations in the alpha2 gene (initiation cd T>C; cd 19 -G; IVS1 -5nt; cd 59 G>A; Hb Quong Sze; Hb Constant Spring; Hb Icaria; Hb Pakse; Hb Koya Dora; polyA-1; polyA-2).

RESULTS

Reliable genotyping of recombinant mutant clones and reference DNA samples was achieved by means of two corresponding test strips presenting parallel arrays of allele-specific oligonucleotides. The entire procedure from blood sampling to the identification of mutations required less than 6 h, and hybridization/detection was manual or automated. The diagnostic potential of this Alpha-Globin StripAssay was carefully evaluated on 272 pre-typed samples in a multicenter validation study. In 96.14% of the cases, StripAssay typing was completely concordant with the reference methods.

CONCLUSIONS

The Alpha-Globin StripAssay proved to be a fast, easy-to-perform and reliable screening method to identify >90% of alpha-globin mutations in endemic areas worldwide.

Homozygosity mapping in consanguineous families reveals extreme heterogeneity of non-syndromic autosomal recessive mental retardation and identifies 8 novel gene loci

Autosomal recessive gene defects are arguably the most important, but least studied genetic causes of severe cognitive dysfunction. Homozygosity mapping in 78 consanguineous Iranian families with nonsyndromic autosomal recessive mental retardation (NS-ARMR) has enabled us to determine the chromosomal localization of at least 8 novel gene loci for this condition. Our data suggest that in the Iranian population NS-ARMR is very heterogeneous, and they argue against the existence of frequent gene defects that account for more than a few percent of the cases.

Sensorineural deafness and male infertility: a contiguous gene deletion syndrome

BACKGROUND

Syndromic hearing loss that results from contiguous gene deletions is uncommon. Deafness-infertility syndrome (DIS) is caused by large contiguous gene deletions at 15q15.3.

METHODS

Three families with a novel syndrome characterised by deafness and infertility are described. These three families do not share a common ancestor and do not share identical deletions. Linkage was established by completing a genome-wide scan and candidate genes in the linked region were screened by direct sequencing.

RESULTS

The deleted region is about 100 kb long and involves four genes (KIAA0377, CKMT1B, STRC and CATSPER2), each of which has a telomeric duplicate. This genomic architecture underlies the mechanism by which these deletions occur. CATSPER2 and STRC are expressed in the sperm and inner ear, respectively, consistent with the phenotype in persons homozygous for this deletion. A deletion of this region has been reported in one other family segregating male infertility and sensorineural deafness, although congenital dyserythropoietic anaemia type I (CDAI) was also present, presumably due to a second deletion in another genomic region.

CONCLUSION

We have identified three families segregating an autosomal recessive contiguous gene deletion syndrome characterised by deafness and sperm dysmotility. This new syndrome is caused by the deletion of contiguous genes at 15q15.3.

C677T methylentetrahydrofulate reductase and angiotensin converting enzyme gene polymorphisms in patients with Alzheimer's disease in Iranian population

In recent years numerous data suggest that vascular risk factors may be play a role in Alzheimer's disease (AD). To determine the association of AD with methylentetrahydrofulate reductase (MTHFR) and angiotensin converting enzyme (ACE) as two main vascular risk factors, we examined MTHFR C677T and ACE insertion/deletion (I/D) gene polymorphism in 117 late-onset AD cases and 125 controls. We found no difference in ACE I/D genotype distribution between AD cases and control (P > 0.05) but there was a significant association between AD and the common MTHFR polymorphism C677T. The T allele conferred an increased risk of AD compared to carrying a C allele (P = 0.001, OR = 1.97, 95% CI: 1.3-2.09). Our result suggests a significant increase in risk of AD in cases with the MTHFR T allele, atleast in the Iranian population.

Attention-deficit/hyperactivity disorder (ADHD) association with the DAT1 core promoter −67 T allele

Association between attention deficit hyperactivity disorder (ADHD) and the 10-repeat allele of a polymorphism (a 40 bp variable number of tandem repeats) in the dopamine transporter gene (DAT1) has been reported by several groups. In this study, we examined whether either allele of the DAT1 core promoter -67 functional polymorphism is associated with ADHD in a case/control study. The allele and genotype frequencies of the polymorphism were studied in 110 patients and 120 controls, which were matched on the basis of sex, age and ethnicity. The genotype frequencies in the patients group were as follows: AA 19.2%; AT 65.2%; TT 15.4% vs. the genotype frequencies in the control group: AA 47.5%; AT 43.3%; TT 9.2% [chi2=20.73, df=2, P<or=0.0001]. The T allele of the -67A/T polymorphism revealed an approximately 1.56-fold excess in the patients group comparing with the controls [chi2=14.50, df=1 (P<or=0.001). For the first time, these findings provide tentative evidence of the contribution of the DAT1 gene core promoter polymorphism to the etiopathophysiology of ADHD at least in the Iranian population that we have studied. Further work is warranted to confirm this finding and to assess its generalization to other ethnic groups.

The cypriot and Iranian National Mutation Frequency Databases

The National Mutation Frequency Databases are continuously updated mutation depositories, which contain extensive information over the described genetic heterogeneity of an ethnic group or population. Here, we report the construction of the Cypriot (http://www.goldenhelix.org/cypriot) and Iranian National Mutation Frequency Databases (http://www.goldenhelix.org/iranian), both derived from an academic effort to provide high quality and up-to-date information on the underlying genetic heterogeneity of inherited disorders in the Cypriot and Iranian populations, respectively. Both databases have been built and maintained online using ETHNOS platform, a specialized software, which provides the means for national mutation database construction and curation. Each database contains brief summaries of the various genetic disorders studied for each population, and an easy-to-use query interface provides, both to specialist as well as to non-specialist users (i.e. patients and their families), instant access to the list and frequencies of the different mutations responsible for the inherited disorders in these populations. Furthermore, numerous links to the respective Online Mendelian Inheritance in Man (OMIM) entries and, when available, to the locus-specific databases fruitfully integrate the databases content into a single Web site. Both databases can serve as valuable online tools for molecular genetic testing of inherited disorders in these populations and could potentially motivate further investigations of yet unknown genetic diseases in the Cypriot and Iranian populations.

Association of AKT1 haplotype with the risk of schizophrenia in Iranian population

AKT-glycogen synthase kinase 3beta (GSK3beta) signaling is a target of lithium and has been implicated in the pathogenesis of mood disorders and schizophrenia. AKT1 protein level is decreased in the peripheral lymphocytes and brains of schizophrenic patients. The SNP2/3/4 TCG haplotype of AKT1 was associated with schizophrenia in patients with Northern European origin. In the present study, we genotyped five single nucleotide polymorphisms (SNP1-5) of AKT1 gene according to the original study in Iranians comprising of 321 schizophrenic patients and 383 controls, all residing in Mashhad city, Northeastern Iran. Haplotype analysis showed that the frequency of a five-SNP haplotype (AGCAG) was significantly higher in schizophrenic patients (0.068) than that of controls (0.034) (P = 0.03 after Bonferroni correction, OR = 2.04, CI = 1.2-3.4). In stratified analysis by schizophrenia subtypes, the frequency of the same haplotype was significantly higher in disorganized subtype (n = 78, frequency of haplotype=0.081) when compared with normal controls (P = 0.04 after Bonferroni correction, OR = 2.59, CI = 1.3-5.2). Our findings did not confirm the association of AKT1 SNP2/3/4 TCG haplotype with the risk of schizophrenia as reported in the original study but showed the evidence of association with a different haplotype, AKT1 five-SNP AGCAG haplotype, with the risk of schizophrenia in Iranian population.

The Coxsackievirus and Adenovirus Receptor: a new adhesion protein in cochlear development

The Coxsackievirus and Adenovirus Receptor (CAR) is an essential regulator of cell growth and adhesion during development. The gene for CAR, CXADR, is located within the genomic locus for Usher syndrome type 1E (USH1E). Based on this and a physical interaction with harmonin, the protein responsible for USH1C, we hypothesized that CAR may be involved in cochlear development and that mutations in CXADR may be responsible for USH1E. The expression of CAR in the cochlea was determined by PCR and immunofluorescence microscopy. We found that CAR expression is highly regulated during development. In neonatal mice, CAR is localized to the junctions of most cochlear cell types but is restricted to the supporting and strial cells in adult cochlea. A screen of two populations consisting of non-syndromic deaf and Usher 1 patients for mutations in CXADR revealed one haploid mutation (P356S). Cell surface expression, viral receptor activity, and localization of the mutant form of CAR were indistinguishable from wild-type CAR. Although we were unable to confirm a role for CAR in autosomal recessive, non-syndromic deafness, or Usher syndrome type 1, based on its regulation, localization, and molecular interactions, CAR remains an attractive candidate for genetic deafness.

Fourteen-Year Experience of Prenatal Diagnosis of Thalassemia in Iran

For 14 years, Iranian scientists have worked to develop a national thalassemia prevention program. Although historically abortion was considered unacceptable in Iran, intensive consultations led to the clerical approval of induced abortion in cases with beta-thalassemia major in 1997, and a nationwide prevention program with screening, counseling and prenatal diagnosis (PND) networks has been developed. This paper reports the experience from one of the two national PND reference laboratories. As one of the oldest reference laboratories, we performed a total of 906 PND in 360 couples at risk for thalassemia from 1990 to 2003. Direct and indirect mutation detection methods were applied for all cases. In total, 22 mutations were tested routinely, and an additional 30 rare mutations were identified. 208 fetuses were found to be normal, 215 fetuses had beta-thalassemia major, and 435 fetuses were carriers of the trait. In 40 cases, we only defined one allele. In 8 cases, we were unable to provide any diagnosis, corresponding to 0.9%. Our data support the functionality of the Iranian beta-thalassemia prevention program. The success of this system in Iran, a multiethnic and Islamic-based country, would mean that it might be applied as an adaptive system for neighboring and other Islamic countries.

A point mutation at the calreticulin gene core promoter conserved sequence in a case of schizophrenia

Exposure to atypical antipsychotic drugs such as valproate increases the expression of chaperones that assist in the folding of proteins in the endoplasmic reticulum (ER) including calreticulin, GRP78/BiP, GRP94, and PD1. This neuroprotective role may be involved in the pathophysiology of neuropsychiatric disorders such as schizophrenia and bipolar disorder. The 5'-flanking region of the human calreticulin gene was screened in 100 cases of schizophrenia by PCR/SSCA between -485 and +1 basepair (bp) relative to the transcription start site. A G > C point mutation was detected at -48 in a case of paranoid schizophrenia, which was not detected in 280 unrelated control subjects (560 chromosomes). This is the first report of mutation in relation with the calreticulin gene. The -48G > C mutation creates a CpG site at the core promoter region of the gene. The role of this mutation remains to be clarified in the pathophysiology of the disease.

Determining the cause of patchwork HBA1 and HBA2 genes: recurrent gene conversion or crossing over fixation events

BACKGROUND AND OBJECTIVES

Recombinations are common between the two homologous alpha-globin genes. We report on the identification and characterization of two patchwork alpha-globin genes.

DESIGN AND METHODS

Multiplex polymerase chain reaction assays were performed to rule out the presence of alpha-globin gene deletions and triplications. The HBA1 (alpha1-globin) and HBA2 (alpha2-globin) genes were individually amplified and sequenced.

RESULTS

Two variants of the HBA1 and HBA2 genes were identified. One variant allele, alpha121, consists primarily of the HBA1 gene sequence except for a small segment of IVSII in which an octanucleotide segment has been replaced by an HBA2 -specific nucleotide. Conversely, the alpha212 variant consists primarily of the HBA2 gene sequence except for a segment of IVSII in which HBA2 -specific nucleotides at two sites have been replaced by HBA1-specific sequences. Both variant alleles are found in individuals of different ethnicity, geographical origin, and haplotype backgrounds. The simplest model for the origins of these patchwork alleles is a single crossover between a normal allele and an existing recombinant allele such as the -alpha(3.7) single gene deletion or the alphaalphaalpha(anti3.7) triplicated allele, but we cannot exclude a reciprocal double crossover or a non-reciprocal gene conversion between misaligned HBA1 and HBA2 genes.

INTERPRETATION AND CONCLUSIONS

The a-globin patchwork alleles have arisen independently on several occasions, most likely through a single crossover between a normal and a recombinant allele. Further studies are necessary to evaluate the possible effect of these changes on alpha-globin gene expression.

SNP array-based homozygosity mapping reveals MCPH1 deletion in family with autosomal recessive mental retardation and mild microcephaly

Very little is known about the molecular basis of autosomal recessive MR (ARMR) because in developed countries, small family sizes preclude mapping and identification of the relevant gene defects. We therefore chose to investigate genetic causes of ARMR in large consanguineous Iranian families. This study reports on a family with six mentally retarded members. Array-based homozygosity mapping and high-resolution microarray-based comparative genomic hybridization (array CGH) revealed a deletion of approximately 150-200 kb, encompassing the promoter and the first six exons of the MCPH1 gene, one out of four genes that have been previously implicated in ARMR with microcephaly. Reexamination of affected individuals revealed a high proportion of prematurely condensed chromosomes, which is a hallmark of this condition, but in spite of the severity of the mutation, all patients showed only borderline to mild microcephaly. Therefore the phenotypic spectrum of MCPH1 mutations may be wider than previously assumed, with ARMR being the only consistent clinical finding.

Mutation of COL11A2 causes autosomal recessive non-syndromic hearing loss at the DFNB53 locus

BACKGROUND

Allele variants of COL11A2, encoding collagen type XI alpha2, cause autosomal dominant non-syndromic hearing loss (ARNSHL) at the DFNA13 locus (MIM 601868) and various syndromes that include a deafness phenotype.

OBJECTIVE

To describe a genome-wide scan carried out on a consanguineous Iranian family segregating ARNSHL.

RESULTS

Genotyping data identified a novel locus for ARNSHL on chromosome 6p21.3, which was designated DFNB53. Homozygosity for the P621T mutation of COL11A2 was present in all deaf persons in this family; this same variation was absent in 269 Iranian controls. Sequence comparison of collagen type XI alpha1 and alpha2 peptides across species shows that the replaced proline is an evolutionarily conserved amino acid.

CONCLUSIONS

The P621T mutation of COL11A2 affects the Y position of the canonical -Gly-X-Y- repeat in collagens. It lies near the amino-terminus of the triple helical region and causes ARNSHL. This finding suggests that mutation type and location are critical determinants in defining the phenotype of COL11A2 associated diseases.

Association analysis of the dopamine transporter (DAT1)-67A/T polymorphism in bipolar disorder

An imbalance in the dopaminergic system in humans has been hypothesized to contribute to the pathogenesis of a number of psychiatric illnesses, including bipolar disorder, schizophrenia, and attention deficit hyperactivity disorder. We performed a case/control study on the DAT1 (HUGO approved symbol SL6A3) gene core promoter polymorphism -67A/T to analyze the possible association of either allele of this polymorphism with bipolar disorder. The allele and genotype frequencies of the polymorphism were studied in 136 patients and 163 controls, which were matched on the basis of sex, age, and ethnicity. The genotype frequencies in the patients group were as follows: AA 30.9%; AT 55.1%; TT 14% versus the genotype frequencies in the control group: AA 49%; AT 41.8%; TT 9.2% [chi2 = 10.3, df = 2, OR = 2.15 (95% CI 1.34-3.47, P < or = 0.006]. The T-allele of the -67A/T polymorphism revealed a approximately 1.4-fold excess in the patients group comparing with the controls (P < or = 0.003). For the first time, these findings provide tentative evidence of the contribution of the DAT1 gene core promoter polymorphism to the etiopathophysiology of bipolar disorder at least in the Iranian population that we have studied. Interestingly, no allelic or genotype association was observed in the female patients (P < or = 0.6 and P < or = 0.7, respectively). Replication studies of independent samples and family-based association studies are necessary to further evaluate the significance of our findings.

Association between the DRD2 A1 allele and opium addiction in the Iranian population

Dysfunction of the central dopaminergic neurotransmission has been suggested to play an important role in the etiology of certain neuropsychiatric disorders such as drug abuse. It has been shown that the dopamine D2 receptor (DRD2) gene dysfunction is associated with multi-drug addiction. Addiction to opium is the most common form of drug abuse in Iran. We studied the allelic association between DRD2 Taq I A polymorphism in 100 opium-dependent Iranian patients and 130 unrelated controls. A 310 bp (base pair) region surrounding Taq I site at the DRD2 locus was amplified by polymerase chain reaction (PCR) and the PCR product was incubated with Taq I restriction enzyme. The A1 allele remained intact while the A2 allele was cut. Significant association was observed between A1 allele and addiction in the patients group (P < 0.0001). Moreover, the frequency of A1A1 genotype was significantly higher in opium users than controls (P < 0.0001). Our result indicates that DRD2 might be involved in the pathophysiology of opium addiction.

Prognostic value of chromosome 1 and 8 copy number in invasive ductal breast carcinoma among Iranian women: an interphase FISH analysis

Breast cancer is amongst the leading causes of death in women worldwide and the most common cancer amongst Iranian women. Unfortunately, the current clinical and histological criteria can only help 60 percent of women with breast cancer in diagnosis and long-term treatment. Therefore, genetic markers both at single gene and chromosomal level can play an important role in improving the diagnosis and prognosis of breast cancer patients. The aim of this retrospective study was to investigate the role of chromosome 1 and 8 copy number assessed by interphase fluorescence in situ hybridization (FISH), as prognostic parameters in 50 Iranian women, aged 35 to 64 years, with sporadic invasive ductal breast carcinoma. Chromosome 1 and 8 copy numbers were evaluated in relation to established clinicopathological parameters, the immunohistochemical markers ER, PR, P53 and cathepsin D, DNA index by flow cytometry, age and survival status of the patients. FISH using centromeric probes for chromosomes 1 and 8 was applied to interphase cell suspensions prepared from archived, Carnoyfixed tumor cells and selected paraffin-embedded tumor sections. Aneusomy for chromosomes 1 and 8 was present in all 50 patients to different levels. The total abnormality rate for chromosome 1 was 33.92 percent (4.24 percent monosomy and 29.68 percent polysomy), whereas for chromosome 8 this rate was 28.30 percent (6.48 percent monosomy and 21.82 percent polysomy). Statistically significant association (p<0.05) was demonstrated between monosomy 1 and patients' age below 50 years, and between monosomy 1 and poor survival, respectively. Disomy 8 was significantly associated with P53 expression. A borderline significant correlation was demonstrated between polysomy 8 and diploid DNA content, as well as between disomy 1 and disease-free status of the patients. Chromosome 1 and 8 copy numbers may be considered as useful prognostic markers in invasive ductal carcinoma of the breast.

GJB2 mutations: Passage through Iran

Hereditary hearing loss (HHL) is a very common disorder. When inherited in an autosomal recessive manner, it typically presents as an isolated finding. Interestingly and unexpectedly, in spite of extreme heterogeneity, mutations in one gene, GJB2, are the most common cause of congenital severe-to-profound deafness in many different populations. In this study, we assessed the contributions made by GJB2 mutations and chromosome 13 g.1777179_2085947del (the deletion more commonly known as del (GJB6-D13S1830) that includes a portion of GJB6 and is hereafter called Delta(GJB6-D13S1830)) to the autosomal recessive non-syndromic deafness (ARNSD) genetic load in Iran. Probands from 664 different nuclear families were investigated. GJB2-related deafness was found in 111 families (16.7%). The carrier frequency of the 35delG mutation showed a geographic variation that is supported by studies in neighboring countries. Delta(GJB6-D13S1830) was not found. Our prevalence data for GJB2-related deafness reveal a geographic pattern that mirrors the south-to-north European gradient and supports a founder effect in southeastern Europe.

Association of the dopamine transporter gene (DAT1) core promoter polymorphism -67T variant with schizophrenia

Dysfunction of the central dopaminergic neurotransmission has been suggested to play an important role in the etiology of schizophrenia. The dopamine transporter (DAT1) mediates the active reuptake of dopamine from the synapses and thereby plays a key role in the regulation of the dopaminergic neurotransmission. In this study, we sought to determine the possible association of the DAT1 gene core promoter polymorphism -67A/T with schizophrenia in a case/control study. The allele and genotype frequencies of the polymorphism were studied in 100 patients and 100 controls, which were matched on the basis of sex, age, and ethnicity. The genotype frequencies in the patients group were as follows: AA 29%; AT 59%; TT 12% versus the genotype frequencies in the control group: AA 57%; AT 38%; TT 5% [chi2 = 16.54, df = 2, OR = 2.25 (95% CI 1.46-3.45, P < or = 0.0003]. For the first time, these findings provide tentative evidence for the contribution of the DAT1 gene core promoter polymorphism to the etiopathophysiology of schizophrenia at least in the Iranian male population that we studied. Replication studies of independent samples and family-based association studies are necessary to further evaluate the significance of our findings.

A novel homozygous missense mutation in the GNE gene of a patient with quadriceps-sparing hereditary inclusion body myopathy associated with muscle inflammation

An adult-onset hereditary inclusion body myopathy with sparing of the quadriceps muscle was originally described in Iranian Jews and assigned to a locus on chromosome 9p12-p13. Recently, mutations of the UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE) gene were reported to cause hereditary inclusion body myopathy and one type of distal myopathy in a world-wide distribution. Importantly, the lack of muscle inflammation was used to distinguish hereditary inclusion body myopathy from the sporadic form of inclusion body myopathy. We report a case of a quadriceps-sparing myopathy in a non-Jewish, Iranian patient with a high degree of muscle inflammation. A novel homozygous G-to-A mutation (128933G-->A) in exon 7 changing a valine to isoleucine (V367I) in the epimerase domain of the GNE gene was found. We conclude that muscle inflammation is not sufficient to exclude the diagnosis of hereditary inclusion body myopathy.