Mohammad-Reza Ghasemi

Bardet–Biedl syndrome (BBS, OMIM 209900) is a rare autosomal recessive disorder characterized by a broad spectrum of clinical features including renal anomalies, learning disabilities, postaxial polydactyly, retinal dystrophy, obesity, and hypogonadism. BBS is a heterogeneous syndrome, both genetically and clinically. To date, genetic variants in more than 28 genes have been associated with this syndrome and its subtypes. Most previous studies on BBS have failed to show clear genotype–phenotype correlations. In order to investigate the spectrum of genetic variation among Iranian BBS patients, 9 subjects from 9 different families with clinically diagnosed BBS were included in this study. Following informed consent, we applied exome sequencing (ES) to the proband and their parents. We next performed Sanger sequencing to validate the identified variants. ES successfully detected four known variants: two in the BBS9 gene, c.2014C > T (p.Gln672Ter) and c.1789 + 1 G > A, one variant in the BBS10 gene (c.728_731del; p.Lys243Ilefs*15), and one variant in the MKKS gene (c.515_516del; p.Glu172Alafs*19). ES also detected two new variants in the BBS7 gene, c.880G > C (p.Gly294Arg) and c.719G > A (p.Gly240Asp), one new variant in the CEP290 gene, c.5159C > G (p.Thr1720Arg), and one new variant, in the TTC8 gene, c.462_465del (p.Ser155Glufs*20). In addition, ES identified one novel homozygous deletion of exon 16 in the BBS9 gene. Among the clinical manifestations observed, obesity and polydactyly were the most common findings. Our findings further support the high heterogeneity of BBS: by discovering known, new, and novel pathogenic variants. We expand the mutational spectrum of BBS-related genes and contribute to the understanding of this multisystem disease.

Background: X‐linked intellectual disability (XLID) is a genetically heterogeneous disorder that results in cognitive impairment and developmental delays. Mutations in the KDM5C gene have been identified as a causative factor in XLID. This study aimed to identify novel variants associated with XLID and to investigate the clinical and genetic characteristics of XLID patients with mutations in the KDM5C gene. This study also conducted a narrative review of the literature to identify key clinical and genetic characteristics of XLID caused by mutations in the KDM5C gene.Study Design: Whole‐exome sequencing was performed on the proband's DNA, and Sanger sequencing was used to confirm and analyze the identified variant in a 20‐month‐old male patient with motor and speech delays. Moreover, a comprehensive literature review was conducted to gather previously reported cases, providing insights into the molecular findings and clinical characteristics of this disorder.Results: The study identified a novel variant, c.2704C>T:p.Gln902X, located in exon 19 of the KDM5C gene (NM_004187.5) using Whole exome sequencing (WES), highlighting the utility of this approach in identifying rare genetic disorders. The analysis also revealed the variable clinical features associated with KDM5C‐related disorders and identified missense variants as the most prevalent among the reported variants.Conclusions: This study provides insights into the clinical and genetic characteristics of XLID associated with KDM5C gene mutations, highlighting the higher manifestation of seizures in males and also addressing the heterogeneity of phenotypes in females.It also identifies a novel pathogenic variant and emphasizes the importance of considering gender‐specific factors and further research to understand the underlying molecular mechanisms.CLINVAR Accession Number: SCV004034082

Hereditary sensory and autonomic neuropathy type 9 (HSAN9) is a rare genetic disorder caused by genetic alterations in the TECPR2 locus and is characterized by developmental and intellectual disability, respiratory dysfunction, gastroesophageal reflux disease (GERD), and sensory and autonomic dysfunction, which are shared among the HSAN family. Whole-exome sequencing (WES) was performed on samples from both probands, and the relevant genetic variants were confirmed in their families using Sanger sequencing. Additionally, a comprehensive literature review was conducted on previously reported cases of HSAN9, and the clinical and genetic data were assessed to provide insight into the genetic and clinical characteristics of the disease. We identified two new cases of HSAN9 with a shared novel variant of TECPR2 (NM_014844.5), c.1568del: p.Ser523PhefsTer12, classified as pathogenic according to ACMG guidelines. The probands showed characteristics of GERD, respiratory dysfunction, gait abnormalities, and developmental and speech delay, and both cases were deceased as a result of severe respiratory infection. The results of the literature review included 34 cases from 9 studies, revealing a wide range of genetic and clinical characteristics. Our study identified two new cases of HSAN9 with a novel variant in TECPR2, confirmed by WES. The clinical characteristics of the patients as well as the conduction of a comprehensive literature review are crucial in the early diagnosis and management of the disease and establishment of genotype-phenotype correlations.

Glycogen storage diseases (GSDs) are a group of rare inherited metabolic disorders characterized by clinical, locus, and allele heterogeneity. This study aims to investigate the phenotype and genotype spectrum of GSDs in a cohort of 14 families from Iran using whole-exome sequencing (WES) and variant analysis. WES was performed on 14 patients clinically suspected of GSDs. Variant analysis was performed to identify genetic variants associated with GSDs. A total of 13 variants were identified, including six novel variants, and seven previously reported pathogenic variants in genes such as AGL, G6PC, GAA, PYGL, PYGM, GBE1, SLC37A4, and PHKA2. Most types of GSDs observed in the cohort were associated with hepatomegaly, which was the most common clinical presentation. This study provides valuable insights into the phenotype and genotype spectrum of GSDs in a cohort of Iranian patients. The identification of novel variants adds to the growing body of knowledge regarding the genetic landscape of GSDs and has implications for genetic counseling and future therapeutic interventions. The diverse nature of GSDs underscores the need for comprehensive genetic testing methods to improve diagnostic accuracy. Continued research in this field will enhance our understanding of GSDs, ultimately leading to improved management and outcomes for individuals affected by these rare metabolic disorders.

Background The ultra-rare autosomal recessive genetic disorder, You-Hoover-Fong Syndrome (YHFS), is caused by defects in the TELO2 gene and is characterized by intellectual disability, developmental delay, and ocular impairments. This study aims to contribute to a better understanding of YHFS by reviewing previous cases and introducing a novel variant in a new case. Methods Whole exome sequencing (WES) was conducted on the proband to identify genetic variants, and Sanger sequencing was used to confirm variants within the family. This article presents a comprehensive collection of reported cases of YHFS, incorporating both molecular and clinical data, through an extensive literature search and analysis of English-language studies published until June 2023. Results Using WES, a novel homozygous missense variant, c.1799A > G (p. Tyr600Cys), was identified in the TELO2 gene in a 4-year-old Iranian male patient. Novel clinical features, including choanal atresia and clubfoot, were also identified. A comprehensive literature review identified 27 patients with YHFS, with 20 variants in the TELO2 gene. Missense pathogenic variants were the most common type of pathogenic variant, and the most common features were microcephaly and intellectual impairment. Conclusion This study presents the first case of pathogenic variants in TELO2 gene in Iran, expands the genotypic and phenotypic spectrum of YHFS and contributes to the growing body of literature pertaining to YHFS. Furthermore, our findings highlight the importance of genetic testing for non-consanguineous carrier screening, as compound heterozygosity may be a significant factor in the development of YHFS. Further research is needed to clarify the molecular mechanisms underlying YHFS pathogenesis. Graphical Abstract

Background: Cornelia de Lange Syndrome (CdLS) is a rare genetic disorder characterized by a range of physical, cognitive, and behavioral abnormalities. This study aimed to perform a comprehensive review of the literature on CdLS and investigate two cases of CdLS with distinct phenotypes that underwent WES to aid in their diagnosis. Methods: We conducted a comprehensive review of the literature on CdLS along with performing whole-exome sequencing on two CdLS patients with distinct phenotypes, followed by Sanger sequencing validation and in-silico analysis. Results: The first case exhibited a classic CdLS phenotype, but the initial WES analysis of blood-derived DNA failed to identify any mutations in CdLS-related genes. However, a subsequent WES analysis of skin-derived DNA revealed a novel heterozygous mutation in the NIPBL gene (NM_133433.4:c.6534_6535del, p.Met2178Ilefs*8). The second case was presented with a non-classic CdLS phenotype, and WES analysis of blood-derived DNA identified a heterozygous missense variant in the SMC1A gene (NM_006306.4:c.2320G>A, p.Asp774Asn). Conclusions: The study shows the importance of considering mosaicism in classic CdLS cases and the value of WES for identifying genetic defects. These findings contribute to our understanding of CdLS genetics and underscore the need for comprehensive genetic testing to enhance the diagnosis and management of CdLS patients.

This review article presents an in-depth analysis of the current state of research on receptor tyrosine kinase regulatory non-coding RNAs (RTK-RNAs) in solid tumors. RTK-RNAs belong to a class of non-coding RNAs (nc-RNAs) responsible for regulating the expression and activity of receptor tyrosine kinases (RTKs), which play a critical role in cancer development and progression. The article explores the molecular mechanisms through which RTK-RNAs modulate RTK signaling pathways and highlights recent advancements in the field. This include the identification of potential new RTK-RNAs and development of therapeutic strategies targeting RTK-RNAs. While the review discusses promising results from a variety of studies, encompassing in vitro, in vivo, and clinical investigations, it is important to acknowledge the challenges and limitations associated with targeting RTK-RNAs for therapeutic applications. Further studies involving various cancer cell lines, animal models, and ultimately, patients are necessary to validate the efficacy of targeting RTK-RNAs. The specificity of ncRNAs in targeting cellular pathways grants them tremendous potential, but careful consideration is required to minimize off-target effects, the article additionally discusses the potential clinical applications of RTK-RNAs as biomarkers for cancer diagnosis, prognosis, and treatment. In essence, by providing a comprehensive overview of the current understanding of RTK-RNAs in solid tumors, this review emphasizes their potential as therapeutic targets for cancer while acknowledging the associated challenges and limitations.