Exome sequencing reveals neurodevelopmental genes in simplex consanguineous Iranian families with syndromic autism.

BACKGROUND AND OBJECTIVE: Autosomal recessive genetic disorders pose significant health challenges in regions where consanguineous marriages are prevalent. The utilization of exome sequencing as a frequently employed methodology has enabled a clear delineation of diagnostic efficacy and mode of inheritance within multiplex consanguineous families. However, these aspects remain less elucidated within simplex families. METHODS: In this study involving 12 unrelated simplex Iranian families presenting syndromic autism, we conducted singleton exome sequencing. The identified genetic variants were validated using Sanger sequencing, and for the missense variants in FOXG1 and DMD, 3D protein structure modeling was carried out to substantiate their pathogenicity. To examine the expression patterns of the candidate genes in the fetal brain, adult brain, and muscle, RT-qPCR was employed. RESULTS: In four families, we detected an autosomal dominant gene (FOXG1), an autosomal recessive gene (CHKB), and two X-linked autism genes (IQSEC2 and DMD), indicating diverse inheritance patterns. In the remaining eight families, we were unable to identify any disease-associated genes. As a result, our variant detection rate stood at 33.3% (4/12), surpassing rates reported in similar studies of smaller cohorts. Among the four newly identified coding variants, three are de novo (heterozygous variant p.Trp546Ter in IQSEC2, heterozygous variant p.Ala188Glu in FOXG1, and hemizygous variant p.Leu211Met in DMD), while the homozygous variant p.Glu128Ter in CHKB was inherited from both healthy heterozygous parents. 3D protein structure modeling was carried out for the missense variants in FOXG1 and DMD, which predicted steric hindrance and spatial inhibition, respectively, supporting the pathogenicity of these human mutants. Additionally, the nonsense variant in CHKB is anticipated to influence its dimerization - crucial for choline kinase function - and the nonsense variant in IQSEC2 is predicted to eliminate three functional domains. Consequently, these distinct variants found in four unrelated individuals with autism are likely indicative of loss-of-function mutations. CONCLUSIONS: In our two syndromic autism families, we discovered variants in two muscular dystrophy genes, DMD and CHKB. Given that DMD and CHKB are recognized for their participation in the non-cognitive manifestations of muscular dystrophy, it indicates that some genes transcend the boundary of apparently unrelated clinical categories, thereby establishing a novel connection between ASD and muscular dystrophy. Our findings also shed light on the complex inheritance patterns observed in Iranian consanguineous simplex families and emphasize the connection between autism spectrum disorder and muscular dystrophy. This underscores a likely genetic convergence between neurodevelopmental and neuromuscular disorders.

Analysis of Cytogenetic Abnormalities in Iranian Patients with Syndromic Autism Spectrum Disorder: A Case Series.

Objective: Autism spectrum disorder (ASD) is a heterogeneous neuropsychiatric group of pervasive developmental disorders mainly diagnosed through the complex behavioral phenotype. According to strong genetic involvement, detecting the chromosome regions and the key genes linked to autism can help to elucidate its etiology. The present study aimed to investigate the value of cytogenetic analysis in syndromic autism and find an association between autism and chromosome abnormalities. Materials & Methods: Thirty-six autistic patients from 30 families were recruited, clinically diagnosed with the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5). The syndromic patients with additional clinical features (including development delay, attention deficit, hyperactivity disorder, seizure, and language and intellectual impairment) were selected due to elevating the detection rate. Cytogenetics analysis was performed using GTG banding on the patients' cultured fibroblasts. Moreover, array-comparative genomic hybridization (CGH) was also performed for patients with a de novo and novel variant. Results: Karyotype analysis in 36 syndromic autistic patients detected chromosomal abnormalities in 2 (5.6%) families, including 46,XY,dup(15)(q11.1q11.2) and 46,XX,ins(7)(q11.1q21.3)dn. In the latter, array-CGH detected 3 abnormalities on chromosome 7, including deletion and insertion on both arms: 46,XX,del(7)(q21.11q21.3),dup(7)(p11.2p14.1p12.3)dn. Conclusion: We reported a novel and de novo cytogenetic abnormality on chromosome 7 in an Iranian patient diagnosed with syndromic autism. However, the detection rate in syndromic autism was low, implying that it cannot be utilized as the only diagnostic procedure.

P21-Associated ncRNA DNA Damage-Activated Expression in Bladder Cancer.

Úvod: Dlouhé nekódující ribonukleové kyseliny (long non-coding ribonucleic acids - lncRNA) jsou v poslední době vzhledem ke své úloze v procesu karcinogeneze předmětem zkoumání vědců zabývajících se nádory. Tyto transkripty regulují kritické kroky v normálních buněčných procesech, takže dysregulace jejich exprese se účastní patogeneze karcinomů. Z důvodu své blízkosti k lokusu CDKN1A má ncRNA spojená s P21 aktivovaná poškozením DNA (P21-associated ncRNA DNA damage activated - PANDA) v tomto ohledu zvláštní pozici. Podílí se na regulaci reakce na poškození DNA, stárnutí buněk a proliferace. Materiály a metody: V této studii jsme metodou kvantitativní polymerázové řetězové reakce hodnotili expresi této lncRNA ve tkáních karcinomu močového měchýře, sousedních nerakovinných tkání (adjacent non-cancerous tissues - ANCT) a v normálních vzorcích močového měchýře. Výsledky: Nebyl detekován žádný významný rozdíl v expresi PANDA, a to ani mezi nádorovými tkáněmi a ANCT (poměr exprese = 1,75; p = 0,11) nebo mezi nádorovými tkáněmi a normálními tkáněmi (poměr exprese = 2,72; p = 0,57). Úroveň exprese této lncRNA nebyla spojena s žádnými demografickými ani klinickými údaji o pacientech, jako je grade nádoru nebo recidiva, ani s rizikovými faktory souvisejícími s rakovinou, mezi něž patří např. kouření cigaret nebo závislost na opiu. Závěr: Tato studie tedy naznačuje, že PANDA není zapojena do patogeneze karcinomu močového měchýře. Hodnocení exprese jiných lncRNA by mohlo pomoci při identifikaci biomarkerů pro tyto karcinomy.

Sensitive Monogenic Noninvasive Prenatal Diagnosis by Targeted Haplotyping.

During pregnancy, cell-free DNA (cfDNA) in maternal blood encompasses a small percentage of cell-free fetal DNA (cffDNA), an easily accessible source for determination of fetal disease status in risk families through non-invasive procedures. In case of monogenic heritable disease, background maternal cfDNA prohibits direct observation of the maternally inherited allele. Non-invasive prenatal diagnostics (NIPD) of monogenic diseases therefore relies on parental haplotyping and statistical assessment of inherited alleles from cffDNA, techniques currently unavailable for routine clinical practice. Here, we present monogenic NIPD (MG-NIPD), which requires a blood sample from both parents, for targeted locus amplification (TLA)-based phasing of heterozygous variants selectively at a gene of interest. Capture probes-based targeted sequencing of cfDNA from the pregnant mother and a tailored statistical analysis enables predicting fetal gene inheritance. MG-NIPD was validated for 18 pregnancies, focusing on CFTR, CYP21A2, and HBB. In all cases we could predict the inherited alleles with >98% confidence, even at relatively early stages (8 weeks) of pregnancy. This prediction and the accuracy of parental haplotyping was confirmed by sequencing of fetal material obtained by parallel invasive procedures. MG-NIPD is a robust method that requires standard instrumentation and can be implemented in any clinic to provide families carrying a severe monogenic disease with a prenatal diagnostic test based on a simple blood draw.

FGFR2, FGF8, FGF10 and BMP7 as candidate genes for hypospadias.

Hypospadias is a common malformation, which results from failure of urethral tube closure, and whose molecular mechanisms are still largely unknown. The normal genital development is orchestrated by the urethral plate epithelium (UPE), at the genital tubercle (GT), which has polarizing activity, controlling a network of epithelial-mesenchymal interactions, which, when disturbed, may lead to hypospadias. Homeobox proteins (HOXs), fibroblast growth factors (FGFs) and bone morphogenic proteins (BMPs) are essential in this process. Hypospadias in the Hoxa13 -/- mice occurs as a result of the combined loss of Fgf8 and Bmp7 expression in the UPE. In both Fgf10 and Fgfr2 deficient mutant hypospadic male mice, cell proliferation is arrested prematurely and the maturation of the urethral epithelium is disrupted. Fgf8, Fgf10, and their receptor Fgfr2 are downstream targets of androgens (AR) during external genital development, an important fact given the pivotal role of AR in male sex differentiation. Therefore, we examined FGFR2, FGF10, FGF8, and BMP7 as candidate genes for hypospadias. DNA from 60 boys with familial, isolated, hypospadias was screened for mutations in FGFR2, FGF10, FGF8, and BMP7 genes, using DHPLC and DNA sequence analysis. The sequence variations c.590C>G and c.582-62G>A in FGF8, and, c.550+27C>T, c.727+180T>G, c.830T>C (p.Me186Thr), and c.2454C>T in FGFR2 were found uniquely in patients with hypospadias, as compared with 96 controls. No genetic variant in the other genes was detected. These results indicate that mutations are rare in FGF8 and FGFR2 in hypospadias, but gene variants may influence the risk.

Association of adenomatous polyposis coli (APC) gene polymorphisms with autism spectrum disorder (ASD).

We serendipitously identified a single nucleotide polymorphism (SNP), 8636C>A (rs1804197) in the 3'-untranslated region of the adenomatous polyposis coli (APC) gene to be associated with autism spectrum disorder (ASD). In order to gain further evidence for the association between the APC locus and ASD, we genotyped four additional adjacent common SNPs (rs2229992, rs42427, rs459552, and rs465899) in the coding regions within the APC gene in a set of Swedish ASDs and controls. One common haplotype TGAG was found to be associated with ASD after haplotype analysis using both Haploview v3.1.1 (P = 0.006) and COCAPHASE v2.403 (P = 0.030). This result is the first to suggest that the genomic locus at APC is associated with ASD, and that the APC gene itself is a good predisposing candidate to be evaluated in future studies due to its important role in neuronal development and function.

Cytokine single nucleotide polymorphisms in Iran.

Overall expression and secretion of cytokines are dependent on genetic nucleotide variations within or adjacent to regulatory regions of cytokine genes. This study allows the comparison of the prevalence of particular genetic markers. In 40 Iranian healthy subjects, cytokine single nucleotide polymorphisms (SNPs) were used to determine allelic and genotypic frequencies for the following cytokine genes: interleukin-1alpha (IL-1alpha) (T/C -889), IL-1beta (C/T -511, T/C +3962), IL-12 ( C/A-1188), interferon-gamma (IFN-gamma) (A/T UTR 5644), transforming growth factor-beta (TGF-beta) (C/T codon 10, G/C codon 25), tumor necrosis factor alpha (TNF-alpha) (G/A -308, G/A -238), IL-2 (T/G -330, G/T +166), IL-4 (T/G -1089, T/C -590, T/C -33), IL-6 (G/C -174, G/A nt565), IL-10 (G/A -1082, C/T -819, C/A -592), IL-1R (C/T pst11970), IL-1RA (T/C mspa 111100), IL-4RA (G/A +1902). All typing was performed using the PCR-SSP assay. Iranian and Italian, English, German, and Greek populations had similar cytokine profiles, but in some cases, the Iranian allele and genotype frequencies were significantly different from those of other Asian and African American populations for the majority of polymorphisms.