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Ahmad S, Ali MZ, Muzammal M, Khan AU, Ikram M, Muurinen M, Hussain S, Loid P, Khan MA, Mäkitie O. Identification of GLI1 and KIAA0825 Variants in Two Families with Postaxial Polydactyly. Genes (Basel) 2023; 14:genes14040869. [PMID: 37107627 PMCID: PMC10137575 DOI: 10.3390/genes14040869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/29/2023] Open
Abstract
Polydactyly is a rare autosomal dominant or recessive appendicular patterning defect of the hands and feet, phenotypically characterized by the duplication of digits. Postaxial polydactyly (PAP) is the most common form and includes two main types: PAP type A (PAPA) and PAP type B (PAPB). Type A involves a well-established extra digit articulated with the fifth or sixth metacarpal, while type B presents a rudimentary or poorly developed superfluous digit. Pathogenic variants in several genes have been identified in isolated and syndromic forms of polydactyly. The current study presents two Pakistani families with autosomal recessive PAPA with intra- and inter-familial phenotype variability. Whole-exome sequencing and Sanger analysis revealed a novel missense variant in KIAA0825 (c.3572C>T: p.Pro1191Leu) in family A and a known nonsense variant in GLI1 (c.337C>T: p.Arg113*) in family B. In silico studies of mutant KIAA0825 and GLI1 proteins revealed considerable structural and interactional modifications that suggest an abnormal function of the proteins leading to the disease phenotype. The present study broadens the mutational spectrum of KIAA0825 and demonstrates the second case of a previously identified GLI1 variant with variable phenotypes. These findings facilitate genetic counseling in Pakistani families with a polydactyly-related phenotype.
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Affiliation(s)
- Safeer Ahmad
- Gomal Center of Biochemistry and Biotechnology, Gomal University, Dera Ismail Khan 29050, Pakistan
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Muhammad Zeeshan Ali
- Gomal Center of Biochemistry and Biotechnology, Gomal University, Dera Ismail Khan 29050, Pakistan
| | - Muhammad Muzammal
- Gomal Center of Biochemistry and Biotechnology, Gomal University, Dera Ismail Khan 29050, Pakistan
| | - Amjad Ullah Khan
- Gomal Center of Biochemistry and Biotechnology, Gomal University, Dera Ismail Khan 29050, Pakistan
| | - Muhammad Ikram
- Gomal Center of Biochemistry and Biotechnology, Gomal University, Dera Ismail Khan 29050, Pakistan
| | - Mari Muurinen
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
- Children's Hospital, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
- Folkhälsan Research Center, Folkhälsan Institute of Genetics, 00290 Helsinki, Finland
| | - Shabir Hussain
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Petra Loid
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
- Children's Hospital, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
- Folkhälsan Research Center, Folkhälsan Institute of Genetics, 00290 Helsinki, Finland
| | - Muzammil Ahmad Khan
- Gomal Center of Biochemistry and Biotechnology, Gomal University, Dera Ismail Khan 29050, Pakistan
| | - Outi Mäkitie
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
- Children's Hospital, University of Helsinki and Helsinki University Hospital, 00290 Helsinki, Finland
- Folkhälsan Research Center, Folkhälsan Institute of Genetics, 00290 Helsinki, Finland
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Yao Y, Deng S, Zhu F. Prenatal Detection of Novel Compound Heterozygous Splice Site Variants of the KIAA0825 Gene in a Fetus with Postaxial Polydactyly Type A. Genes (Basel) 2022; 13:genes13071230. [PMID: 35886013 PMCID: PMC9316509 DOI: 10.3390/genes13071230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/03/2022] [Accepted: 07/07/2022] [Indexed: 01/25/2023] Open
Abstract
Postaxial polydactyly (PAP) is a common abnormality characterized by extra digits on hands and/or feet. To date, sequence variants in seven genes have been identified in non-syndromic PAP. In the present study, a fetus manifesting non-syndromic postaxial polydactyly type A (PAPA) was found by fetal ultrasonography. To better evaluate fetal prognosis, SNP array analysis and trio whole-exome sequencing (trio-WES) were performed to identify the underlying etiology. Although SNP array analysis revealed no abnormality, trio-WES identified compound heterozygous splice site variants in KIAA0825, c.-1-2A>T and c.2247-2A>G in intron 2 and intron 12, respectively. These two splice site variants were absent in control databases and were predicted to influence splicing by in silico analysis. To confirm the potential pathogenicity of the variants, in vitro splicing assays using minigene and RNA from peripheral leukocytes of the heterozygous parents were conducted. Minigene and RT-PCR assays demonstrated that the c.-1-2A>T variant led to the loss of the initiation codon, and the c.2247-2A>G variant mainly resulted in exon 13 skipping. Prenatal WES and subsequent functional studies are important approaches for defining the genetic etiology of fetuses with PAPA and are also essential for accurate genetic counseling and decision making. Taken together, this study expands the spectrum of KIAA0825 variations in PAPA patients and increases the knowledge of the molecular consequences of KIAA0825 splice site variants.
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Affiliation(s)
- Yanyi Yao
- Medical Genetic Center, Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430070, China;
| | - Shan Deng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China;
| | - Feng Zhu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China;
- Correspondence: ; Tel.: +86-027-8572-6012
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