Genome-wide single nucleotide polymorphism-based autozygosity mapping facilitates identification of mutations in consanguineous families with epidermolysis bullosa

Autozygosity mapping (AM) is a technique utilised for mapping homozygous autosomal recessive (AR) traits and facilitation of genetic diagnosis. We investigated the utility of AM for the molecular diagnosis of heterogeneous AR disorders, using epidermolysis bullosa (EB) as a paradigm. We applied this technique to a cohort of 46 distinct EB families using both short tandem repeat (STR) and genome-wide single nucleotide polymorphism (SNP) array-based AM to guide targeted Sanger sequencing of EB candidate genes. Initially, 39 of the 46 cases were diagnosed with homozygous mutations using this method. Independently, 26 cases, including the seven initially unresolved cases, were analysed with an EB-targeted next-generation sequencing (NGS) panel. NGS identified mutations in five additional cases, initially undiagnosed due to the presence of compound heterozygosity, deep intronic mutations or runs of homozygosity below the set threshold of 2 Mb, for a total yield of 44 of 46 cases (95.7) diagnosed genetically. © 2018 John Wiley & Sons Ltd

Development and implementation of a novel panel consisting 20 markers for the detection of genetic causes of male infertility

Azoospermia factor (AZF) genes are involved in spermatogenesis. Deletions in the region of these genes have been recognised as a major genetic cause of infertility due to defects in spermatogenesis. Klinefelter syndrome (KS) is the other main cause of male infertility. This study was performed to establish a novel method for the detection of genetic causes of infertility in males and also to investigate the prevalence, extent and position of Y chromosome microdeletions in Iranian infertile men. We developed a newly designed panel of fluorescent multiplex-PCR method to amplify 20 markers (15 sequence-tagged sites (STSs) markers which are placed in the Y chromosome AZF region, 2 short tandem repeats (STRs) and 3 segmental duplications (SDs)). This multifunctional method is for the simultaneous detection of Y chromosome microdeletions and KS. Among 149 studied infertile men, one was detected to suffer from KS and seven (4.7) were detected with the presence of one or more deleted STS loci. The main cause of infertility for the remaining patients would be nongenetic factors. This strategy is represented as a fast and accurate method to determine the frequencies of different AZF microdeletions which are suitable for use in clinical purposes. © 2017 Blackwell Verlag Gmb

Development and implementation of a novel panel consisting 20 markers for the detection of genetic causes of male infertility

Azoospermia factor (AZF) genes are involved in spermatogenesis. Deletions in the region of these genes have been recognised as a major genetic cause of infertility due to defects in spermatogenesis. Klinefelter syndrome (KS) is the other main cause of male infertility. This study was performed to establish a novel method for the detection of genetic causes of infertility in males and also to investigate the prevalence, extent and position of Y chromosome microdeletions in Iranian infertile men. We developed a newly designed panel of fluorescent multiplex-PCR method to amplify 20 markers (15 sequence-tagged sites (STSs) markers which are placed in the Y chromosome AZF region, 2 short tandem repeats (STRs) and 3 segmental duplications (SDs)). This multifunctional method is for the simultaneous detection of Y chromosome microdeletions and KS. Among 149 studied infertile men, one was detected to suffer from KS and seven (4.7) were detected with the presence of one or more deleted STS loci. The main cause of infertility for the remaining patients would be nongenetic factors. This strategy is represented as a fast and accurate method to determine the frequencies of different AZF microdeletions which are suitable for use in clinical purposes. © 2017 Blackwell Verlag Gmb

Recessive mutation in tetraspanin CD151 causes Kindler syndrome-like epidermolysis bullosa with multi-systemic manifestations including nephropathy

Epidermolysis bullosa (EB) is caused by mutations in as many as 19 distinct genes. We have developed a next-generation sequencing (NGS) panel targeting genes known to be mutated in skin fragility disorders, including tetraspanin CD151 expressed in keratinocytes at the dermal-epidermal junction. The NGS panel was applied to a cohort of 92 consanguineous families of unknown subtype of EB. In one family, a homozygous donor splice site mutation in CD151 (NM139029; c.351 + 2T > C) at the exon 5/intron 5 border was identified, and RT-PCR and whole transcriptome analysis by RNA-seq confirmed deletion of the entire exon 5 encoding 25 amino acids. Immunofluorescence of proband's skin and Western blot of skin proteins with a monoclonal antibody revealed complete absence of CD151. Transmission electron microscopy showed intracellular disruption and cell-cell dysadhesion of keratinocytes in the lower epidermis. Clinical examination of the 33-year old proband, initially diagnosed as Kindler syndrome, revealed widespread blistering, particularly on pretibial areas, poikiloderma, nail dystrophy, loss of teeth, early onset alopecia, and esophageal webbing and strictures. The patient also had history of nephropathy with proteinuria. Collectively, the results suggest that biallelic loss-of-function mutations in CD151 underlie an autosomal recessive mechano-bullous disease with systemic features. Thus, CD151 should be considered as the 20th causative, EB-associated gene. © 2017 Elsevier B.V

Recessive mutation in tetraspanin CD151 causes Kindler syndrome-like epidermolysis bullosa with multi-systemic manifestations including nephropathy

Epidermolysis bullosa (EB) is caused by mutations in as many as 19 distinct genes. We have developed a next-generation sequencing (NGS) panel targeting genes known to be mutated in skin fragility disorders, including tetraspanin CD151 expressed in keratinocytes at the dermal-epidermal junction. The NGS panel was applied to a cohort of 92 consanguineous families of unknown subtype of EB. In one family, a homozygous donor splice site mutation in CD151 (NM139029; c.351 + 2T > C) at the exon 5/intron 5 border was identified, and RT-PCR and whole transcriptome analysis by RNA-seq confirmed deletion of the entire exon 5 encoding 25 amino acids. Immunofluorescence of proband's skin and Western blot of skin proteins with a monoclonal antibody revealed complete absence of CD151. Transmission electron microscopy showed intracellular disruption and cell-cell dysadhesion of keratinocytes in the lower epidermis. Clinical examination of the 33-year old proband, initially diagnosed as Kindler syndrome, revealed widespread blistering, particularly on pretibial areas, poikiloderma, nail dystrophy, loss of teeth, early onset alopecia, and esophageal webbing and strictures. The patient also had history of nephropathy with proteinuria. Collectively, the results suggest that biallelic loss-of-function mutations in CD151 underlie an autosomal recessive mechano-bullous disease with systemic features. Thus, CD151 should be considered as the 20th causative, EB-associated gene. © 2017 Elsevier B.V

Genome-wide single nucleotide polymorphism-based autozygosity mapping facilitates identification of mutations in consanguineous families with epidermolysis bullosa

Autozygosity mapping (AM) is a technique utilised for mapping homozygous autosomal recessive (AR) traits and facilitation of genetic diagnosis. We investigated the utility of AM for the molecular diagnosis of heterogeneous AR disorders, using epidermolysis bullosa (EB) as a paradigm. We applied this technique to a cohort of 46 distinct EB families using both short tandem repeat (STR) and genome-wide single nucleotide polymorphism (SNP) array-based AM to guide targeted Sanger sequencing of EB candidate genes. Initially, 39 of the 46 cases were diagnosed with homozygous mutations using this method. Independently, 26 cases, including the seven initially unresolved cases, were analysed with an EB-targeted next-generation sequencing (NGS) panel. NGS identified mutations in five additional cases, initially undiagnosed due to the presence of compound heterozygosity, deep intronic mutations or runs of homozygosity below the set threshold of 2 Mb, for a total yield of 44 of 46 cases (95.7) diagnosed genetically. © 2018 John Wiley & Sons Ltd

Inherited Interleukin 2-Inducible T-Cell (ITK) Kinase Deficiency in Siblings With Epidermodysplasia Verruciformis and Hodgkin Lymphoma

Biallelic mutations in the ITK gene cause a T-cell primary immunodeficiency with Epstein-Barr virus (EBV)-lymphoproliferative disorders. We describe a novel association of a homozygous ITK mutation with β-human papillomavirus (HPV)-positive epidermodysplasia verruciformis. Thus, loss of function in ITK can result in broad dysregulation of T-cell responses to oncogenic viruses, including β-HPV and EBV. © The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: [email protected]

Recalcitrant Cutaneous Warts in a Family with Inherited ICOS Deficiency

Recalcitrant warts, caused by human papillomaviruses (HPVs), can be a cutaneous manifestation of inborn error of immunity. This study investigated the clinical manifestations, immunodeficiency, single-gene susceptibility, and HPV repertoire in a consanguineous family with severe sinopulmonary infections and recalcitrant warts. Clinical and immunologic evaluations, including FACS and lymphocyte transformation test, provided evidence for immunodeficiency. Combined whole-exome sequencing and genome-wide homozygosity mapping were utilized to disclose candidate sequence variants. Whole-transcriptome sequencing was used to concomitantly investigate the HPV genotypes and the consequences of detected sequence variants in the host. The proband, a male aged 41 years, was found to be homozygous for the c.6delG, p.Lys2Asnfs�17 variant in ICOS, encoding the inducible T-cell costimulator. This variant was located inside the 5 megabase of runs of homozygosity on 2q33.2. RNA sequencing confirmed the deleteriousness of the ICOS variant in three skin biopsies revealing significant downregulation of ICOS and its ligand, ICOSLG. Reads unaligned to the human genome were applied to 926 different viruses, and α-HPV57, β-HPV107, β-HPV14, and β-HPV17 were detected. Collectively, we describe a previously unrecognized inborn error of T-cell immunity to HPVs, indicating that autosomal recessive ICOS deficiency can underlie recalcitrant warts, emphasizing the immunologic underpinnings of recalcitrant warts at the nexus of human and viral genomic variation. © 2022 The Author

Whole-transcriptome sequencing�based concomitant detection of viral and human genetic determinants of cutaneous lesions

Severe viral infections of the skin can occur in patients with inborn errors of immunity (IEI). We report an all-in-one whole-transcriptome sequencing�based method by RNA-Seq on a single skin biopsy for concomitantly identifying the cutaneous virome and the underlying IEI. Skin biopsies were obtained from healthy and lesional skin from patients with cutaneous infections suspected to be of viral origin. RNA-Seq was utilized as the first-tier strategy for unbiased human genome-wide rare variant detection. Reads unaligned to the human genome were utilized for the exploration of 926 viruses in a viral genome catalog. In 9 families studied, the patients carried pathogenic variants in 6 human IEI genes, including IL2RG, WAS, CIB1, STK4, GATA2, and DOCK8. Gene expression profiling also confirmed pathogenicity of the human variants and permitted genome-wide homozygosity mapping, which assisted in identification of candidate genes in consanguineous families. This automated, online, all-in-one computational pipeline, called VirPy, enables simultaneous detection of the viral triggers and the human genetic variants underlying skin lesions in patients with suspected IEI and viral dermatosis. Copyright: © 2022, Saeidian et al