Biallelic loss of LDB3 leads to a lethal pediatric dilated cardiomyopathy

Autosomal dominant variants in LDB3 (also known as ZASP), encoding the PDZ-LIM domain-binding factor, have been linked to a late onset phenotype of cardiomyopathy and myofibrillar myopathy in humans. However, despite knockout mice displaying a much more severe phenotype with premature death, bi-allelic variants in LDB3 have not yet been reported. Here we identify biallelic loss-of-function variants in five unrelated cardiomyopathy families by next-generation sequencing. In the first family, we identified compound heterozygous LOF variants in LDB3 in a fetus with bilateral talipes and mild left cardiac ventricular enlargement. Ultra-structural examination revealed highly irregular Z-disc formation, and RNA analysis demonstrated little/no expression of LDB3 protein with a functional C-terminal LIM domain in muscle tissue from the affected fetus. In a second family, a homozygous LDB3 nonsense variant was identified in a young girl with severe early-onset dilated cardiomyopathy with left ventricular non-compaction; the same homozygous nonsense variant was identified in a third unrelated female infant with dilated cardiomyopathy. We further identified homozygous LDB3 frameshift variants in two unrelated probands diagnosed with cardiomegaly and severely reduced left ventricular ejection fraction. Our findings demonstrate that recessive LDB3 variants can lead to an early-onset severe human phenotype of cardiomyopathy and myopathy, reminiscent of the knockout mouse phenotype, and supporting a loss of function mechanism.

Motivations and personality characteristics of candidate sperm and oocyte donors according to parenthood status: a national study from the french CECOS network

STUDY QUESTION

In a non-commercial national gamete donation programme, do the motivations and personality characteristics of candidate sperm and oocyte donors differ according to their parenthood status?

SUMMARY ANSWER

Moderate differences exist between non-parent and parent candidate donors in motivations for gamete donation and representations as well as in personality characteristics.

WHAT IS KNOWN ALREADY

Several studies have analysed the motivations and experiences of oocyte or sperm donors, but mainly in countries where gamete donation is a commercial transaction, and very few studies have reported results of personality traits using personality inventory tests. No study has specifically investigated the motivations and personality characteristics of candidate gamete donors according to parenthood status.

STUDY DESIGN, SIZE, DURATION

A prospective study was carried out including 1021 candidate donors from 21 centres (in university hospitals) of the national sperm and egg banking network in France between November 2016 and December 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 1021 candidate gamete donors were included in the study. During their first visit, male (n = 488) and female candidate donors (n = 533) completed a questionnaire on sociodemographic characteristics, their motivations for donation and their representations of donation, infertility and family. Secondly, a NEO Personality Inventory (NEO-PI-R) exploring the Big Five personality traits was completed online. Results were compared between parent and non-parent candidate donors.

MAIN RESULTS AND THE ROLE OF CHANCE

Altruistic values were the principal motive for donation irrespective of parenthood status. Reassurance about their fertility or preservation of sperm for future use was more often reported in non-parent than in parent candidate donors. With regard to representation of gamete donation or of the family, independently of their parenthood status, candidate donors more frequently selected social rather than biological representations. Mean personality characteristics were in the normal range. Non-parent candidate donors had higher scores on openness and depression than parents, while parent candidate donors appeared more social than non-parents.

LIMITATIONS, REASONS FOR CAUTION

The personality characteristics inventory was not completed by all candidate donors included in the study. However, family status did not differ between the two groups (NEO-PI-R completed (n = 525) or not), while the group who completed the NEO-PI-R had a higher educational level. This national study was performed in a country where gamete donation is subject to strict legislation.

WIDER IMPLICATIONS OF THE FINDINGS

In a global context where reproductive medicine is commercialized and gamete donor resources are limited, this study found that altruism and social representations of gamete donation and family are the main motivations for gamete donation in a country which prohibits financial incentive. These findings are relevant for health policy and for gamete donation information campaigns.

STUDY FUNDING/COMPETING INTEREST(S)

Grant from the Agence de la Biomédecine, France. The authors have nothing to disclose related to this study.

TRIAL REGISTRATION NUMBER

N/A.

Clinical and genetic profile of children with unexplained intellectual disability/developmental delay and epilepsy

OBJECTIVE

This study was conducted to evaluate the validity of performing whole exome sequencing in children with unexplained intellectual disability (ID), developmental delay (DD), and epilepsy.

METHODS

We enrolled 61 Iranian children with unexplained DD/ID, and epilepsy with no etiologic diagnosis. 64 % of cases were male and 36 % were female, with a mean age of 6.2 years (range, 38 days to 15 years). Approximately 79 % of patients were born to consanguineous parents or had non-related parents from a highly inbred local region. Whole-exome sequencing analysis followed by Sanger sequencing was performed in all patients.

RESULTS

Pathogenic/likely pathogenic variants were identified in 59% (36/61) of patients, consisting of 26 novel and 14 known alterations. Variants of unknown significance were observed in 6.5 % (4/61) of patients. Variants in 28 genes have not been previously reported in Iranian patients with ID. Several additional phenotypes, mostly microcephaly, were common in 57.4 % of cases. Additionally, epilepsy was refractory in 40 % of patients. Three groups of brain anomalies consisting of brain dysgenesis, brain atrophy, and leukodystrophy were identified in our cohort. Mutations in genes implicated in cellular metabolic pathways were the most common, followed by ion channel/ion transporter and transcription pathways.

DISCUSSION

High-throughput DNA sequencing of the Iranian population with a high rate of parental consanguinity is a valuable strategy for identifying genetic etiology in children with unexplained ID/DD and epilepsy. Determining the genetic basis and most commonly involved pathways may help to identify novel genes and targeted antiepileptic treatments.

Autozygosity-driven genetic diagnosis in consanguineous families from Italy and the Greater Middle East

Autozygosity-driven exome analysis has been shown effective for identification of genes underlying recessive diseases especially in countries of the so-called Greater Middle East (GME), where high consanguinity unravels the phenotypic effects of recessive alleles and large family sizes facilitate homozygosity mapping. In Italy, as in most European countries, consanguinity is estimated low. Nonetheless, consanguineous Italian families are not uncommon in publications of genetic findings and are often key to new associations of genes with rare diseases. We collected 52 patients from 47 consanguineous families with suspected recessive diseases, 29 originated in GME countries and 18 of Italian descent. We performed autozygosity-driven exome analysis by detecting long runs of homozygosity (ROHs > 1.5 Mb) and by prioritizing candidate clinical variants within. We identified a pathogenic synonymous variant that had been previously missed in NARS2 and we increased an initial high diagnostic rate (47%) to 55% by matchmaking our candidate genes and including in the analysis shorter ROHs that may also happen to be autozygous. GME and Italian families contributed to diagnostic yield comparably. We found no significant difference either in the extension of the autozygous genome, or in the distribution of candidate clinical variants between GME and Italian families, while we showed that the average autozygous genome was larger and the mean number of candidate clinical variants was significantly higher (p = 0.003) in mutation-positive than in mutation-negative individuals, suggesting that these features influence the likelihood that the disease is autozygosity-related. We highlight the utility of autozygosity-driven genomic analysis also in countries and/or communities, where consanguinity is not widespread cultural tradition.

Non-syndromic cleft palate: Association analysis on three gene polymorphisms of the folate pathway in Asian and Italian populations

Periconceptional folic acid supplementation can reduce the risk of inborn malformations, including orofacial clefts. Polymorphisms of MTHFR, TCN2, and CBS folate-related genes seem to modulate the risk of cleft lip with or without cleft palate (CL/P) in some populations. CL/P and cleft palate only (CPO) are different malformations that share several features and possibly etiological causes. In the present investigation, we conducted a family-based, candidate gene association study of non-syndromic CPO. Three single nucleotide polymorphisms, namely, rs1801133 of MTHFR, rs1801198 of TCN2, and rs4920037 of CBS, were investigated in a sample that included 129 Italian and 65 Asian families. No evidence of association between the three genotyped polymorphisms and CPO was found in the Italian and Asian cases, indeed the transmission disequilibrium test did not detect any asymmetry of transmission of alleles. This investigation, although with some limitation, further supports that CL/P and CPO diverge in their genetic background.

Final results for the neutron -asymmetry parameter A0 from the UCNA experiment

The UCNA experiment was designed to measure the neutron β-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A0.

The neutron electric dipole moment experiment at the Spallation Neutron Source

Novel experimental techniques are required to make the next big leap in neutron electric dipole moment experimental sensitivity, both in terms of statistics and systematic error control. The nEDM experiment at the Spallation Neutron Source (nEDM@SNS) will implement the scheme of Golub & Lamoreaux [Phys. Rep., 237, 1 (1994)]. The unique properties of combining polarized ultracold neutrons, polarized 3He, and superfluid 4He will be exploited to provide a sensitivity to ∼ 10−28 e · cm. Our cryogenic apparatus will deploy two small (3 L) measurement cells with a high density of ultracold neutrons produced and spin analyzed in situ. The electric field strength, precession time, magnetic shielding, and detected UCN number will all be enhanced compared to previous room temperature Ramsey measurements. Our 3He co-magnetometer offers unique control of systematic effects, in particular the Bloch-Siegert induced false EDM. Furthermore, there will be two distinct measurement modes: free precession and dressed spin. This will provide an important self-check of our results. Following five years of “critical component demonstration,” our collaboration transitioned to a “large scale integration” phase in 2018. An overview of our measurement techniques, experimental design, and brief updates are described in these proceedings.

ROCK1 is associated with non-syndromic cleft palate

BACKGROUND

Craniofacial morphogenesis is the result of an intricate multistep network of tightly controlled spatial and temporal signalling that involves several molecules and transcription factors organized into highly coordinated pathways. Any alteration in even one step of this delicate process can lead to congenital malformations such as cleft palate. One of the first steps in embryonal orofacial development is the migration of cells from the neural crests to the branchial arches. Next, the cells have to proliferate, differentiate, move and connect to each other in order to correctly form the palate. Cell contraction, promoted by the interaction of non-muscle myosin II and actin A, is a crucial step in morphogenesis and is regulated by ROCK1 protein.

METHODS

A family-based association study was carried out in order to verify whether or not genetic variants of ROCK1 were associated with non-syndromic cleft palate (nsCP). Two cohorts from Italy and Iran, a total of 189 nsCP cases and their parents were enrolled.

RESULTS

The rs35996865-G allele was under-transmitted in cases of nsCP [P = .006, odds ratio (OR) = 0.63 (95% CI 0.45-0.88)].

CONCLUSION

This investigation reveals for the first time data supporting a role for ROCK1 in nsCP aetiology.

Investigation continuous noise exposure and occupational performance of the workers in the pharmaceutical industry: A Case Study in an Ampoule and Vial Production Industry

Introduction: Exposure to noise is considered as one of the most important health problems in various industries, especially pharmaceutical industry, which can ultimately lead to significant negative effects on labor force and occupational performance. The aim of this study was to investigate the relationship between continuous noise exposure and occupational performance of the workers in the pharmaceutical industry and ampoule production line in Iran. Method: This cross-sectional study was conducted through a descriptive-analytical method in 2015. The subjects were 100 workers exposed to noise in an ampoule and vial manufacturing factory in Iran. The sound measurement was carried out in accordance with ISO 9612: 2009. The Hersey and Goldsmith questionnaire (ACHIEVE model) was used to investigate the workers’ occupational performance, and the seven dimensions of the questionnaire as well as the final score of occupational performance was determined for each individual. Results: The results showed that there was a low inverse relationship between noise exposure and occupational performance of the total workers in all the halls which was statistically significant (P-value = 0/01, r2 = 0/256). It was also found that there was an inverse relationship between exposure to noise and the seven dimensions, but the relationship was statistically significant only for the dimensions of ability, clarity, and evaluation (P-value <0.05). Conclusion: The present study showed that the workers in the pharmaceutical industry and ampoule production line were often exposed to higher-than-permitted sound level, and such exposures had negative effects on their occupational performance.

Search for neutron dark decay: n → χ + e+e−

In January, 2018, Fornal and Grinstein proposed that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in two different types of experiments. One of the possible final states discussed includes a single χ along with an e+e− pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ∼ 4π acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). We use the timing information of coincidence events to select candidate dark sector particle decays by applying a timing calibration and selecting events within a physically-forbidden timing region for conventional n → p + e- + ν̅e decays. The summed kinetic energy (Ee+e−) from such events is reconstructed and used to set limits, as a function of the χ mass, on the branching fraction for this decay channel.

Decline in peripheral blood NKG2D+CD3+CD56+ NKT cells in metastatic colorectal cancer patients

OBJECTIVE

Colorectal cancer (CRC) is one of the main causes of cancer deaths in the world. This cancer can be divided into non-metastatic and metastatic CRC stages. CD3+CD56+ NKT cell subsets are a minor T cell subset in peripheral blood and conduct the killing of tumor cells in direct manner. Little is obvious about levels and surface markers of these cells such as NKG2D in different cancers, especially in CRC.

METHODS

We included 15 non-metastatic (low-grade), 11 non-metastatic (high-grade), 10 metastatic colorectal cancer patients and 18 healthy controls. The percentages of CD3+CD56+ NKT cells and NKG2D+CD56+ NKT cells from samples were analyzed by flow cytometry in peripheral blood mononuclear cells (PBMCs) of samples.

RESULTS

We found that there was a significantly lower number of NKG2D+CD3+CD56+ cells in peripheral blood of patients with metastatic colorectal cancer compared with normal controls (77.53 ± 5.79 % vs 90.74 ± 9.84 %; p<0.01).

CONCLUSION

The fact that frequency of NKG2D+CD56+ NKT cells was significantly lower in patients with metastatic colorectal cancer compared to healthy controls strengthens the hypothesis that NKT cells can play a substantial role in the protection against human colorectal cancer, and this opens up avenues for novel studies about elucidating the other aspects of tumor surveillance in CRC progression and immunotherapy (Tab. 2, Fig. 2, Ref. 46).

Consanguineous marriages in the genetic counseling centers of Isfahan and the ethical issues of clinical consultations

Consanguineous marriage, which is common in many regions in the world, has absorbed much attention as a causative factor in raising the incidence of genetic diseases. The adverse effects may be attributed to the expression of the genes received from common ancestors and mortality and morbidity of the offspring. Iran has a high rate of consanguineous marriages. In recent years genetic counseling has come to be considered in health care services. This cross-sectional study was conducted in order to determine the prevalence and types of consanguineous marriages in the genetic clinics in Isfahan. We aimed to define the different types of marriages, specific categories of genetic disorders associated with consanguineous marriages, and mode of inheritance in the family tree. We also narratively reviewed the ethical aspects of the issue. The data were collected using a simple questionnaire. A total number of 1535 couples from urban and rural areas formed the study population. The marriages were classified according to the degree of the relationship between couples, including: double cousin, first cousin, first cousin once removed, second cousin and beyond second cousin. The SPSS software version 16 was used for data analysis. Data obtained through genetic counseling offered during a 5-year period revealed that 74.3% had consanguineous relationships, 62.3% were first cousins, 1% were double cousins and 7.8% were second cousins. In addition, 76% of the couples had at least one genetic disease in their family tree. Related ethical issues were also considered in this study, including autonomy and informed decision making, benefit and harm assessment, confidentiality, ethics in research, justice in access to counseling services, financial problems ethics, and the intellectual property of scientific success.

Prevalence of 22q11.2 microdeletion syndrome in Iranian patients with cleft palate

Background:

22q11.2 microdeletion syndrome is the most common multiple genetic disorder associated with learning disabilities, developmental delays, immune deficiency, hypocalcemia, and cleft palate. Finding some valid criteria for screening of 22q11.2 deletion syndromes in infants would be very helpful in early diagnosis and treatment.

Materials and Methods:

Since 69% of individuals with 22q11.2 deletion have a palatal abnormality, we studied the prevalence of 22q11.2 deletion syndrome in 378 Iranian patients during a 5-year period, including 291 patients affected with cleft palate only without cleft lip (CPO) and 87 patients affected with velopharyngeal incompetence (VPI) and/or submucous cleft palate (SMCP). DNA copy number was analyzed with multiplex ligation-dependent probe amplification (MLPA) technique.

Results:

In our study, 15/378 (3.97%) patients with palatal anomalies showed 22q11.2 deletion. Interestingly, this prevalence between syndromic patients was 15/104 (14.42%).

Conclusion:

It seems that SMCP or VPI, in addition to one or more another features of 22q11.2 deletions, especially developmental delay, may be good criteria for molecular investigation of 22q11.2 region.

Association between mismatch repair gene MSH3 codons 1036 and 222 polymorphisms and sporadic prostate cancer in the Iranian population

The mismatch repair system (MMR) is a post-replicative DNA repair mechanism whose defects can lead to cancer. The MSH3 protein is an essential component of the system. We postulated that MSH3 gene polymorphisms might therefore be associated with prostate cancer (PC). We studied MSH3 codon 222 and MSH3 codon 1036 polymorphisms in a group of Iranian sporadic PC patients. A total of 60 controls and 18 patients were assessed using the polymerase chain reaction and single strand conformational polymorphism. For comparing the genotype frequencies of patients and controls the chi-square test was applied. The obtained result indicated that there was significantly association between G/A genotype of MSH3 codon 222 and G/G genotype of MSH3 codon 1036 with an increased PC risk (P=0.012 and P=0.02 respectively). Our results demonstrated that MSH3 codon 222 and MSH3 codon 1036 polymorphisms may be risk factors for sporadic prostate cancer in the Iranian population.

Reciprocal 22q11.2 Deletion and Duplication in Siblings with Karyotypically Normal Parents

The 22q11.2 locus is known to harbor a high risk for structural variation caused by non-allelic homologous recombination, resulting in deletions and duplications. Here, we describe the first family with one sibling carrying the 22q11 deletion and the other carrying the reciprocal duplication. FISH and SNP array analysis of the parents show a maternal origin for both deletion and duplication, without indications of balanced deletions/duplications or mosaicism. We hypothesize that germline mosaicism in the mother underlies the deletion and duplication, which would implicate a high recurrence risk for her offspring.

[Significant association between nonsyndromic cleft lip with or without cleft palate and IRF6rs2235371 polymorphism in Iranian familiar population]

According to previous studies the IRF6rs2235371 polymorphism is a risk factor for NSCL/P in different populations. However our recent study revealed no correlation between IRF6rs642961 and NSCL/P in our population. In the present study we have investigated the relationship between IRF6rs2235371 and NSCL/P in same group to determine whether IRF6rs2235371 is a risk factor in our population as well. We analyzed the IRF6rs2235371 genotype in a subset of the Iranian population using the Polymerase Chain Reaction technique. The PCR products were digested with DpnII. Chi-square test was applied to analyze the obtained result. The patients were supplied by the Cleft Lip and Palate Clinic of the Isfahan University of Medical Science. A clinician ascertained the non-syndromic status of all patients and that no clefting drugs, ethanol or smoking were abused during pregnancy. The control group was selected from unaffected subjects with no history of NSCL/P in their families. 107 patients from 107 Iranian unrelated families and 100 controls were screened. There was a significant association between the IRF6rs2235371 genotype sand an increased NSCL/P risk. Our data indicates that the IRF6rs2235371 variation can increase the risk of NSCL/P in the Iranian population. This result is in contrast with the results of our recent study on the correlation between the IRF6rs642961 polymorphism and NSCL/P in the same group.

Surface osteosarcoma: Clinical features and therapeutic implications

INTRODUCTION

Surface osteosarcoma are rare variant of osteosarcoma that include parosteal osteosarcoma, periosteal osteosarcoma and high grade surface osteosarcoma. These lesions have different clinical presentation and biological behavior compared to conventional osteosarcoma, and hence need to be managed differently.

GOAL

The aim of this study is to analyze the clinico-pathological features and outcome of a series of surface osteosarcoma in an attempt to define the adequate treatment of this rare entity.

PATIENT AND METHOD

It is a retrospective and bicentric study of 18 surface osteosarcoma that were seen at the KASSAB's Institute and SAHLOUL Hospital from 2006 to 2013. The authors reviewed the clinical and radiologic features, histologic sections, treatments, and outcomes in this group of patients.

RESULTS

Seven patients were male (38.9%) and 11 were female (61.1%) with mean age of 25 years (range from 16 to 55 years). Eleven lesions were in the femur and 7 in the tibia. We identified 11 parosteal osteosarcoma (six of them were dedifferentiated), 3 periosteal osteosarcoma and 4 high grade surface osteosarcoma. Six patients had neoadjuvant chemotherapy and all lesions had surgical resection. Margins were wide in 15 cases and intra lesional in 3 cases. Histological response to chemotherapy was poor in all cases. The mean follow up was 34.5 months. Six patients (33.3%) presented local recurrence and 8 patients (44.4%) presented lung metastases. Six patients (33.3%) died from the disease after a mean follow up of 12 months (6-30 months); all of them had high grade lesions.

CONCLUSION

Histological grade of malignancy is the main point to assess in surface osteosarcoma since it determines treatment and prognosis. Low grade lesions should be treated by wide resection, while high grade lesions need more aggressive surgical approach associated to post operative chemotherapy.

Non-syndromic cleft lip with or without cleft palate in Asian populations: Association analysis on three gene polymorphisms of the folate pathway

OBJECTIVE

Orofacial clefts (OFCs) are one of the most common birth defects in humans. They are the subject of a number of investigations aimed at elucidating the bases of their complex mode of inheritance involving both genetic and environmental factors. Genes belonging to the folate pathway have been among the most studied. The aim of the investigation was to replicate previous studies reporting evidence of association between polymorphisms of folate related genes and the occurrence of non-syndromic cleft lip with or without cleft palate (NSCL/P), using three independent samples of different ancestry: from Tibet, Bangladesh and Iran, respectively.

DESIGN

Specifically, the polymorphisms rs1801133 of MTHFR, rs1801198 of TCN2, and rs4920037 of CBS, were tested.

RESULTS

A decreased risk of NSCL/P was observed in patients presenting the C677T variant at MTHFR gene (relative risk for heterozygotes=0.53; 95% confidence interval [C.I.]=0.32-0.87). The investigated polymorphisms mapping at TCN2 and CBS genes did not provide any evidence of association.

CONCLUSION

Overall, these results indicate that NSCL/P risk factors differ among populations and confirm the importance of testing putative susceptibility variants in different genetic backgrounds.

Detection of intragenic SMN1 mutations in spinal muscular atrophy patients with a single copy of SMN1

Proximal spinal muscular atrophy is an autosomal recessive disorder characterized by symmetrical muscle weakness due to degeneration of alpha motor neurons in the spinal cord. Homozygous deletions in the SMN1 have been reported in more than 90% of spinal muscular atrophy cases. Compound heterozygous patients account for approximately 4% of spinal muscular atrophy cases. In this study, we performed a quantitative test in 20 of 87 spinal muscular atrophy patients who did not have homozygous deletion of SMN1. Mutation screening of SMN1 gene was performed in 4 patients who have only 1 copy of SMN1 to identify intragenic mutations. In addition to a previously described missense mutation in exon 4 (p.A188S/ c.562G>T), we identified 2 novel mutations including a single nucleotide insertion in exon 7 (c.861_862insT/p.R288X) and a deletion of nucleotide G in exon 3 (c.286delG/p.D96Tfs*53). Our results suggested that about 4% of spinal muscular atrophy patients have subtle mutations and might be considered in laboratory examination.

Genotype-phenotype correlation of survival motor neuron and neuronal apoptosis inhibitory protein genes in spinal muscular atrophy patients from Iran

BACKGROUND

Proximal spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by symmetrical proximal muscle weakness and atrophy. According to the severity of the disease and the age of onset, SMA can be divided into three groups. The survival motor neuron (SMN) gene that is located on 5q13 is identified as the disease determining gene. Another gene in this region is neuronal apoptosis inhibitory protein (NAIP), and its functional role in the pathogenesis of SMA has not been fully elucidated. Here, we investigated the correlation between deletions in SMN and NAIP genes with clinical features of SMA patients.

MATERIALS AND METHODS

In the current study, 71 unrelated Iranian patients were investigated for the detection of deletions in SMN1 and NAIP genes. Polymerase chain reaction (PCR) was used to detect the deletions of exon 4 and 5 of the NAIP gene. Deletions in exon 7 and 8 of SMN1 gene were detected by RFLP-PCR with DraI and DdeI, respectively.

RESULTS

Our results showed that 51 patients have homozygous deletions in SMN1 and/or NAIP genes. Among these 51 patients, deletion in NAIP gene were found in 35 patients (65.7% of type I, 22.5% type II and 11.42% type III).

CONCLUSION

Defect in SMN1 gene plays a major role in manifesting of the disease and NAIP (4 and 5) gene acts as a modifying factor in severity of symptoms. Correlation between NAIP gene defect and severity of the disease is confirmed. However, the exact role of NAIP gene in SMA has yet to be fully clarified.

Evaluation of multiplex ligation-dependent probe amplification analysis versus multiplex polymerase chain reaction assays in the detection of dystrophin gene rearrangements in an Iranian population subset

BACKGROUND

The Duchenne muscular dystrophy (DMD) gene is located in the short arm of the X chromosome (Xp21). It spans 2.4 Mb of the human genomic DNA and is composed of 79 exons. Mutations in the Dystrophin gene result in DMD and Becker muscular dystrophy. In this study, the efficiency of multiplex ligation-dependent probe amplification (MLPA) over multiplex polymerase chain reaction (PCR) assays in an Iranian population was investigated.

MATERIALS AND METHODS

Multiplex PCR assays and MLPA analysis were carried out in 74 patients affected with DMD.

RESULTS

Multiplex PCR detected deletions in 51% of the patients with DMD. MLPA analysis could determine all the deletions detected by the multiplex PCR. Additionally, MLPA was able to identify one more deletion and duplication in patients without detectable mutations by multiplex PCR. Moreover, MLPA precisely determined the exact size of the deletions.

CONCLUSION

Although MLPA analysis is more sensitive for detection of deletions and duplications in the dystrophin gene, multiplex PCR might be used for the initial analysis of the boys affected with DMD in the Iranian population as it was able to detect 95% of the rearrangements in patients with DMD.

Cutis laxa type II with mutation in the pyrroline-5-carboxylate reductase 1 gene

A 14-year-old Iranian boy with congenital cutis laxa and several other typical autosomal recessive type II features was examined. Mutation analysis of the pyrroline-5-carboxylate reductase 1 gene revealed a single-base deletion (c.345delC) in exon 4 leading to frame shift and premature termination of translation.

A novel mutation in the aprataxin (APTX) gene in an Iranian individual suffering early-onset ataxia with oculomotor apraxia type 1(AOA1) disease

BACKGROUND

Ataxia with oculomotor apraxia type 1 (AOA1) shows early onset with autosomal recessive inheritance and is caused by a mutation in the aprataxin (APTX) gene encoding for the APTX protein.

METHODS

In this study, a 7-year-old girl born of a first-cousin consanguineous marriage was described with early-onset progressive ataxia and AOA, with increased cholesterol concentration and decreased albumin concentration in serum. PCR and direct DNA sequencing was performed after DNA extraction.

RESULTS

Sequencing analysis revealed a novel homozygous deletion in c.643 and A>T single nucleotide polymorphism in c.641 in exon 6 of the APTX gene [ENST00000379825].

CONCLUSION

It seems that this region of exon 6 is probably a hot spot; however, no deletions have been reported in exon 6 yet.

An insight into genetics of non-syndromic cleft palate

Our proband is a 29-year-old man, who is affected with soft cleft palate and hypernasality. A study of about six generations of this family pedigree shows that cleft palate has repeatedly occurred in males, with probably a X-linked recessive pattern of inheritance. Interestingly, the sister of the proband is affected with hypernasality and she has an affected son. This is the first report of X-linked inheritance pattern of cleft palate in Iran.

Mutation analysis of CACNA1A gene in Iranian migrainous and review literatures

BACKGROUND

There are contrary results about the role of CACNA1A gene in the causation of common migraine in different populations. However, migraine may be genetically heterogeneous and more studies in different families and populations are required for a definite conclusion. The aim of this study was to surveyed leukocyte genomic DNA mutation of CACNA1A in Iranian migraine patients with [MA] and without aura [MO] who has family history of migraine and we performed a narrative review of all studies that evaluated CACNA1A gene, non-hemiplegic migraine [MA and MO] and FHM [familial hemiplegic migraine].

MATERIALS AND METHODS

The 30 patients with family history of migraine were selected for mutations analysis for CACNA1A gene by PCR method. For review, we searched MEDLINE-PUBMED, ISI, Scopus and Cochrane databases up to December 2012.

RESULTS

Mutation analysis of the 4 exons of the CACNA1A gene in these patients revealed no mutations in this gene. Direct sequencing revealed a polymorphism previously reported G to A transition in the exon 16 [nt2369, G→A] in 9 patients. In review, the correlation of FHM loci [CACNA1A gene] with MA and MO has been showed in different population and only small population from Caucasians presented this correlation.

CONCLUSION

CACNA1A is most likely not a major susceptibility gene for common migraine in Iranian maigrainous. It's essential to study more on larger series and covering all 47 exons of the CACNA1A gene to confirm this hypothesis.

Investigation of TBX1 gene deletion in Iranian children with 22q11.2 deletion syndrome: correlation with conotruncal heart defects

BACKGROUND

DiGeorge syndrome (DGS) is the result of a microdeletion in chromosome 22q11.2 in over 90% of cases. DGS is the second most frequent syndrome after Down syndrome and has an incidence of 1/4000 births. Unequal crossover between low-copy repeats, on the proximal part of the long arm of chromosome 22, usually results in a 3 Mb deletion in one of the chromosome 22 and a reciprocal and similarly sized duplication on the other one. Several studies have indicated that TBX1 (T-box 1) haploinsufficiency is responsible for many of the phenotypic traits of 22q11.2 deletion syndrome. Conotruncal heart defects (CTDs) are present in 75-85% of patients with 22q11.2 deletion syndrome in Western countries.

METHODS

Among 78 patients fulfilling the criteria for DGS diagnosed by the fluorescence in situ hybridisation test, 24 had 22q11.2 deletion. Screening for TBX1 gene deletion was performed by multiplex ligation-dependent probe amplification (MLPA).

RESULTS

Our results revealed that of 24 patients with TBX1 gene deletion, 12 had CTDs while 12 did not show any heart defects.

CONCLUSIONS

Our findings indicate that other genes or gene interactions may play a role in penetrance or the severity of heart disease among patients with DGS.

A case report of 22q11 deletion syndrome confirmed by array-CGH method

Velo-cardio-facial syndrome (VCFS) is caused by a submicroscopic deletion on the long arm of chromosome 22 and affects approximately 1 in 4000 persons, making it the second most prevalent genetic syndrome after Down syndrome and the most common genetic syndrome associated with cleft palate. Most of the 22q11.2 deletion cases are new occurrences or sporadic; however, in about 10 % of families, the deletion is inherited and other family members are affected or at risk for passing this deletion to their children. This report describes a 1.5 years-old male child with clinical signs of velo-cardio-facial syndrome (VCFS) presented with heart defect, soft cleft palate, developmental delay, acrocephaly, seizure, MRI abnormalities and descriptive facial feature, such as hypertelorism. Array-CGH test was done to confirm the diagnosis; the result revealed a 2.6 Mbp deletion in 22q11.2 chromosome that containing TBX1 and COMT genes. Our data suggest that haploinsufficiency of TBX1 gene is probably a major contributor to some of the syndrome characteristic signs, such as heart defect. Because of developmental delay and dysmorphic facial feature were observed in the index's mother and relatives, inherited autosomal dominant form of VCF is probable, and MLPA (multiplex ligation-dependent probe amplification) test should be performed for parents to estimate the recurrent risk in next pregnancy.

Lower oesophageal sphincter pressure and timed barium oesophagogram: two objective parameters in the non-invasive assessment of primary achalasia

BACKGROUND

The non-invasive assessment of primary achalasia is not precise.

AIM

To compare investigations before and 1 month after balloon dilation in achalasia.

METHODS

Fifty-two patients with primary achalasia were enrolled. Subjective and objective variables of oesophageal functions were analysed before and 1 month after balloon dilation.

RESULTS

The mean predilation symptom score, lower oesophageal sphincter pressure, height and volume of barium at 5 min were 7.7 +/- 2.6, 62.0 +/- 25.1 mmHg, 9.2 +/- 6.1 cm and 53.2 +/- 49.8 mL respectively; the mean postdilation values were 3.0 +/- 3.0, 34.1 +/- 12.5 mmHg, 7.9 +/- 5.1 cm and 28.0 +/- 30.1 mL respectively. The before dilation volume of barium at 5 min correlates significantly with lower oesophageal sphincter pressure (P < 0.01). The mean symptom scores, lower oesophageal sphincter pressure and volume of barium at 5 min dropped significantly after intervention (P < 0.01), but the reduction in barium height at 5 min was not significant. The percentage changes in volume at 5 min significantly predicted the percentage changes in lower oesophageal sphincter pressure (P < 0.01).

CONCLUSIONS

The volume of barium retention at 5 min can predict the lower oesophageal sphincter pressure before and after balloon dilation in primary achalasia. This could be used as a non-invasive objective tool for initial and post-dilation assessment.

Absence of linkage and linkage disequilibrium to chromosome 15q11-q13 markers in 139 multiplex families with autism

Chromosomal region 15q11-q13 has been implicated to harbor a susceptibility gene or genes underlying autism. Evidence has been derived from the existence of cytogenetic anomalies in this region associated with autism, and the report of linkage in a modest collection of multiplex families. Most recently, linkage disequilibrium with the marker GABRB3-155CA2 in the candidate locus GABRB3, located in this region, has been reported. We searched for linkage using eight microsatellite markers located in this region of chromosome 15 in 147 affected sib-pairs from 139 multiplex autism families. We also tested for linkage disequilibrium in the same set of families with the same markers. We found no evidence for excess allele sharing (linkage) for the markers in this region. Also, we found no evidence of linkage disequilibrium, including for the locus GABRB3-155CA2. Thus, it appears that the role of this region of chromosome 15 is minor, at best, in the majority of individuals with autism.

A genomic screen of autism: evidence for a multilocus etiology

We have conducted a genome screen of autism, by linkage analysis in an initial set of 90 multiplex sibships, with parents, containing 97 independent affected sib pairs (ASPs), with follow-up in 49 additional multiplex sibships, containing 50 ASPs. In total, 519 markers were genotyped, including 362 for the initial screen, and an additional 157 were genotyped in the follow-up. As a control, we also included in the analysis unaffected sibs, which provided 51 discordant sib pairs (DSPs) for the initial screen and 29 for the follow-up. In the initial phase of the work, we observed increased identity by descent (IBD) in the ASPs (sharing of 51.6%) compared with the DSPs (sharing of 50.8%). The excess sharing in the ASPs could not be attributed to the effect of a small number of loci but, rather, was due to the modest increase in the entire distribution of IBD. These results are most compatible with a model specifying a large number of loci (perhaps >/=15) and are less compatible with models specifying </=10 loci. The largest LOD score obtained in the initial scan was for a marker on chromosome 1p; this region also showed positive sharing in the replication family set, giving a maximum multipoint LOD score of 2.15 for both sets combined. Thus, there may exist a gene of moderate effect in this region. We had only modestly positive or negative linkage evidence in candidate regions identified in other studies. Our results suggest that positional cloning of susceptibility loci by linkage analysis may be a formidable task and that other approaches may be necessary.

Exclusion of linkage to the HLA region in ninety multiplex sibships with autism

Several studies have suggested a role for the histocompatibility complex of loci (HLA) in the genetic susceptibility to autism. We have tested this hypothesis by linkage analysis using genetic marker loci in the HLA region on chromosome 6p in multiplex families with autism. We have examined sharing of alleles identical by descent in 97 affected sib pairs from 90 families. Results demonstrate no deviation from the null expectation of 50% sharing of alleles in this region; in fact, for most marker loci, the observed sharing was less than 50%. Thus, it is unlikely that loci in this region contribute to the genetic etiology of autism to any significant extent in our families.

Comparative studies of the CAG repeats in the spinocerebellar ataxia type 1 (SCA1) gene

The CAG repeat tract at the autosomal dominant spinocerebellar ataxia type 1 (SCA1) locus was analyzed in SCA1 families and French-Acadian, African-American, Caucasian, Greenland Inuit, and Thai populations. The normal alleles had 9-37 repeats, whereas disease alleles contained 44-64 repeats. The CAG repeat tract contained one or two CAT interruptions in 44 of 47 normal human chromosomes and in all five chimpanzees examined. In contrast, no CAT interruptions were found in Old World monkeys or expanded human alleles. The number and positions of CAT interruptions may be important in stabilizing CAG repeat tracts in normal chromosomes. At least five codons occupy the region corresponding to the polyglutamine tract at the SCA1 locus in mice, rats, and other rodents. They comprise three or four CCN (coding for proline) in addition to one or two CAG repeats.

Analysis of CAG repeat of the Machado-Joseph gene in human, chimpanzee and monkey populations: a variant nucleotide is associated with the number of CAG repeats

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder associated with an unstable and expanded CAG repeat. We analyzed this locus from various sources including MJD families, Acadian, African American, Caucasian, Greenland Inuit and Thai populations. The range of the CAG repeat size was 14-40 in the normal alleles while the MJD alleles contained 73-78 repeats in our studies. We found 25 different alleles on normal chromosomes with a heterozygosity of 0.86 in combined populations. The most common alleles were 23 (22.9%) and 14 (25.5%) repeats. We also examined 16 chimpanzees and various Old World monkeys: a pigtail macaque, a mangabey and 12 rhesus macaques. The DNA sequences surrounding the CAG repeat did not vary among species. The range of the number of the CAG repeats is 13-14 in macaques, 16 in mangabey and 14-20 in chimpanzees. Variant CAA or AAG triplets in the CAG repeat tracts were found in all 268 human, 28 monkey and 32 chimpanzee chromosomes. As reported in a previous study [Kawaguchi et al. (1994) Nature Genet. 8, 221-228] the common variant positions were the third (CAA), fourth (AAG) and sixth (CAA) positions. However, we found three human chromosomes containing CAG at the sixth position and the mangabey had AAG at the ninth position. In addition, we found CAG at the fourth position and AAG at the sixth position in all macaque chromosomes. The nucleotide following the CAG repeat tract was usually G in all species studied. However, we sometimes found C at this position in human and chimpanzee chromosomes. Interestingly, this variant C was found in all expanded chromosomes and in 54.5% of chromosomes with 27-40 CAG repeats but it was not found in any chromosomes with less than 20 CAG repeats. We hypothesize that the variant C may be associated with CAG repeat instability.

A locus for axonal motor-sensory neuropathy with deafness and mental retardation maps to Xq24-q26

DNA markers on the X chromosome were used to map the locus for an unusual form of X-linked recessive hereditary motor and sensory neuropathy with associated deafness and mental retardation in a three-generation family that was originally reported by Cowchock et al. (Am, J. Hum. Genet. 35: 85A, 1993; Am. J. Med. Genet. 20: 307-315, 1985). This family included seven affected males, three obligate carrier females, and four unaffected males. The patients were severely affected within the first few years of life with distal weakness, muscle atrophy, sensory loss, areflexia, pes cavus, and hammer toes. Five of the seven affected males showed associated deafness, and three of these five individuals also presented with mental retardation or social developmental delay. Motor nerve conduction velocities in affected males were normal to mildly delayed, and sensory conduction was markedly abnormal. Heterozygous females were asymptomatic. Close linkage to the Xg blood group locus (Xp22) and the PGK locus (Xq13) was previously excluded in this family, while weak linkage of the disease gene to DXYS1 (XQ21.3) was suggested. Our current linkage studies and haplotype analysis of 19 microsatellite markers on the long arm of the X chromosome demonstrate that DXS425 (Xq24) and HPRT (Xq26.1) are flanking markers and that the disease gene is closely linked to the markers DXS1122, DXS994, DXS737, DXS1206, and DXS1047.

The deafness locus (dn) maps to mouse chromosome 19

The deafness mouse has profound sensorineural hearing loss with degeneration of hair cells soon after birth. The mode of inheritance is recessive, and there are no associated phenotypic anomalies. Thus, this mouse provides a model for recessive, non-syndromic, prelingual deafness. We have mapped the gene causing deafness in the mouse to Chromosome (Chr) 19 by analysis of 230 intersubspecific backcross progeny. No recombinants were found with the microsatellite marker D19Mit14. The loci for two guanine nucleotide-binding proteins are tightly linked to this marker, and they are being investigated as possible candidate genes. The identification of the defective gene in the mouse will help to explain the mechanism that causes hair cell degeneration and is likely to identify a homologous gene for deafness in humans.

Mapping of the gene for hormone sensitive lipase (LIPE) to chromosome 19q13.1-->q13.2

Free fatty acids are the major source of fuel for mammals, and hormone sensitive lipase (LIPE) plays a critical role in lipid metabolism by mobilizing free fatty acids from stored triglycerides. We have identified and sequenced a partial cDNA for LIPE. Cosmids were identified by hybridization and mapped to 19q13.1-->q13.2 by FISH. Direct sequence analysis of a 1 kb segment of cosmid 26710 identifies a dinucleotide repeat in an intron upstream of exon 8 of human LIPE. This marker was heterozygous 82% of the time with 12 alleles (166-190 bp) detected in 122 chromosomes. The most likely order for this gene is: qter-[D19S178/LIPE]-(3 cM)-D19S47-(1 cM)-D19S190-RYR1-cen.

A gene for Crouzon craniofacial dysostosis maps to the long arm of chromosome 10

Crouzon craniofacial dysostosis (CFD) is an autosomal dominant craniofacial disorder characterized by premature craniosynostosis, shallow orbits and hypoplastic maxilla. To map the gene responsible, we have used a mapping strategy of testing for linkage to known developmental genes. Analysis of a large kindred established linkage between CFD and three loci (D10S190, D10S209 and D10S216) that span a 13 cM region on chromosome 10q. A maximum pairwise lod score of 4.42 (theta = 0) at D10S190 was obtained and the addition of a second kindred produced a combined pairwise lod score of 5.32 (theta = 0) at the same locus. The developmental gene, PAX2, located within this region, is an attractive candidate gene.

Tightly linked flanking microsatellite markers for the Usher syndrome type I locus on the short arm of chromosome 11

Usher syndrome type I is an autosomal recessive disease characterized by profound congenital hearing impairment and vestibular dysfunction followed by the onset of progressive pigmentary retinopathy in childhood or early adolescence. A locus (USH1C) for one form of this disease was previously assigned to the short arm of chromosome 11 through linkage studies in the Acadian population of southwestern Louisiana. Linkage analyses of a set of microsatellite markers in 27 Acadian families provide evidence that USH1C lies between D11S861 and D11S928. Three markers (D11S419, D11S921, and D11S899) that lie between the flanking markers show no recombination with USH1C, and all 54 chromosomes with the abnormal allele at the disease locus have identical alleles for D11S419 and D11S921. This haplotype was found on only 10 of 50 chromosomes with the normal allele at the disease locus, suggesting a strong founder effect. Of the 54 chromosomes with the abnormal allele, 12 had a divergent allele at D11S899. These results suggest that USH1C is in the 2-3-cM interval between D11S861 and D11S899.

Linkage mapping of the human thromboxane A2 receptor (TBXA2R) to chromosome 19p13.3 using transcribed 3' untranslated DNA sequence polymorphisms

The actions of thromboxane A2 as a prostaglandin mediator are dependent on its recently cloned and sequenced receptor. The identification and characterization of DNA polymorphisms in the thromboxane A2 receptor (TBXA2R) will advance the study of this gene as a candidate in a number of medical disorders. We amplified a 573-nucleotide fragment of the transcribed 3' untranslated region of the TBXA2R gene using the polymerase chain reaction (PCR) and the published cDNA sequence. This region was found to contain two sequence polymorphisms within an Alu. These DNA polymorphisms were demonstrated using an efficient method of direct solid-phase sequence analysis. Three of the four expected alleles were observed in the CEPH families. TBXA2R was localized to chromosome 19 by PCR amplification in a series of monochoromosomal human/rodent somatic cell hybrids. Linkage mapping places TBXA2R closest to the anonymous marker D19S120, with a maximal LOD = 19.55, at a theta = 0.05 in the CEPH panel of DNAs. Multipoint linkage analysis places TBXA2R between the markers D19S120 and PMS207 on the telomeric end of chromosome 19p13.3.

Evidence for genetic heterogeneity in malignant hyperthermia susceptibility

Malignant hyperthermia susceptibility (MHS) is a clinically heterogeneous pharmacogenetic disorder characterized by accelerated metabolism, hyperthermia, and frequently muscle rigidity. MHS is elicited by all commonly used potent inhalation anesthetics and depolarizing neuromuscular blockers and remains an important cause of death due to anesthesia. Recent linkage studies suggest a single genetic locus for this disorder on chromosome 19q13.1. The results of our linkage analyses exclude several loci on 19q13.1 as a site for the gene(s) that produces the MHS phenotype in three unrelated families and clearly establish genetic heterogeneity in this disorder. These results are consistent with the hypothesis that the genetic defect that alters thermoregulation may vary in MHS and that clinical variability in the expression of MHS may be explained by genetic heterogeneity.