Identification of Proximal and Distal 22q11.2 Microduplications among Patients with Cleft Lip and/or Palate: A Novel Inherited Atypical 0.6 Mb Duplication

Misalignments of low-copy repeats (LCRs) located in chromosome 22, particularly band 22q11.2, predispose to rearrangements. A variety of phenotypic features are associated with 22q11.2 microduplication syndrome which makes it challenging for the genetic counselors to recommend appropriate genetic assessment and counseling for the patients. In this study, multiplex ligation probe dependent amplification (MLPA) analysis was performed on 378 patients with cleft lip and/or palate to characterize rearrangements in patients suspected of 22q11.2 microduplication and microdeletion syndromes. Of 378 cases, 15 were diagnosed with a microdeletion with various sizes and 3 with duplications. For the first time in this study an atypical 0.6 Mb duplication is reported. Illustration of the phenotypes associated with the microduplications increases the knowledge of phenotypes reported in the literature

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

Identification of Proximal and Distal 22q11.2 Microduplications among Patients with Cleft Lip and/or Palate: A Novel Inherited Atypical 0.6 Mb Duplication

Misalignments of low-copy repeats (LCRs) located in chromosome 22, particularly band 22q11.2, predispose to rearrangements. A variety of phenotypic features are associated with 22q11.2 microduplication syndrome which makes it challenging for the genetic counselors to recommend appropriate genetic assessment and counseling for the patients. In this study, multiplex ligation probe dependent amplification (MLPA) analysis was performed on 378 patients with cleft lip and/or palate to characterize rearrangements in patients suspected of 22q11.2 microduplication and microdeletion syndromes. Of 378 cases, 15 were diagnosed with a microdeletion with various sizes and 3 with duplications. For the first time in this study an atypical 0.6 Mb duplication is reported. Illustration of the phenotypes associated with the microduplications increases the knowledge of phenotypes reported in the literature

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

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

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

Family-based association analysis between nonsyndromic cleft lip with or without cleft palate and IRF6 polymorphism in an Iranian population.

OBJECTIVES: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is a common birth defect which is strongly associated with genetic factors. Previous studies in several populations showed a significant correlation between IRF6 rs642961 polymorphism and NSCL/P. The aim of this study is to indicate the correlation of IRF6 rs642961 polymorphism and NSCL/P in Iranian NSCL/P families. MATERIAL AND METHODS: In this study, we analyzed IRF6 rs642961 genotype in 352 individuals from 102 Iranian nuclear families affected by NSCL/P using iPlex assay on a Sequenom MassARRAY platform. Hardy-Weinberg equilibrium and Mendelian error checking were performed by Haploview 4.2. Allelic association analysis was conducted with family-based association tests implemented in FBAT program v2.03. RESULTS: The family-based association analysis revealed no significant association between IRF6 rs642961 genotypes and an increased NSCL/P risk. CONCLUSIONS: In contrast to other Asian populations, our study indicates that the IRF6 rs642961 polymorphism cannot be a risk factor for NSCL/P in an Iranian population. CLINICAL RELEVANCE: Genetic factors have an important role in NSCL/P, among which interferon regulatory factor 6 (IRF6) has been reported as a risk factor for NSCL/P in several populations; however, our data indicated no significant association between IRF6 polymorphism and NSCL/P in an Iranian population

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

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

Possible effect of SNAIL family transcriptional repressor 1 polymorphisms in non-syndromic cleft lip with or without cleft palate

OBJECTIVE: Orofacial development is a complex process subjected to failure impairing. Indeed, the cleft of the lip and/or of the palate is among the most frequent inborn malformations. The JARID2 gene has been suggested to be involved in non-syndromic cleft lip with or without cleft palate (nsCL/P) etiology. JARID2 interacts with the polycomb repressive complex 2 (PRC2) in regulating the expression patterns of developmental genes by modifying the chromatin state. MATERIALS AND METHODS: Genes coding for the PRC2 components, as well as other genes active in cell differentiation and embryonic development, were selected for a family-based association study to verify their involvement in nsCL/P. A total of 632 families from Italy and Asia participated to the study. RESULTS: Evidence of allelic association was found with polymorphisms of SNAI1; in particular, the rs16995010-G allele was undertransmitted to the nsCL/P cases [P = 0.004, odds ratio = 0.69 (95% C.I. 0.54-0.89)]. However, the adjusted significance value corrected for all the performed tests was P = 0.051. CONCLUSIONS: The findings emerging by the present study suggest for the first time an involvement of SNAI1 in the nsCL/P onset. CLINICAL RELEVANCE: Interestingly, SNAI1 is known to promote epithelial to mesenchymal transition by repressing E-cadherin expression, but it needs an intact PRC2 to act this function. Alterations of this process could contribute to the complex etiology of nsCL/P