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Chouery E, Tahan E, Karam R, Pharoun J, Mehawej C, Megarbane A. BHLHA9 homozygous duplication in a consanguineous family: A challenge for genetic counseling. Am J Med Genet A 2023; 191:923-929. [PMID: 36565049 DOI: 10.1002/ajmg.a.63094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 12/01/2022] [Accepted: 12/10/2022] [Indexed: 12/25/2022]
Abstract
Split-hand/foot malformation (SHFM) with long-bone deficiency (SHFLD) is a rare condition characterized by SHFM associated with long-bone malformation usually involving the tibia. It includes three different types; SHFLD1 (MIM % 119,100), SHFLD2 (MIM % 610,685) and SHFLD3 (MIM # 612576). The latter was shown to be the most commonly reported with a duplication in the 17p13.1p13.3 locus that was narrowed down to the BHLHA9 gene. Here, we report a consanguineous Lebanese family with three members presenting with limb abnormalities including tibial hemimelia. One of these patients presented with additional bowing fibula and another with bilateral split hand. CGH array analysis followed by RQ-PCR allowed us to detect the first homozygous duplication on the short arm of chromosome 17p13.3 including the BHLHA9 gene and involved in SHFLD3. Interestingly, one patient with the homozygous duplicated region, carrying thus four BHLHA9 copies presented with long bone deficiency but no SHFM. The incomplete penetrance and the variable expressivity of the disease in this family as well as the presence of the BHLHA9 homozygous duplication rendered genetic counseling extremely challenging and preimplantation genetic diagnosis almost impossible.
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Affiliation(s)
- Eliane Chouery
- Department of Human Genetics, Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon
| | - Elio Tahan
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon
| | - Rim Karam
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon
| | - Jana Pharoun
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon
| | - Cybel Mehawej
- Department of Human Genetics, Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon
| | - Andre Megarbane
- Department of Human Genetics, Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon.,Institut Jérôme Lejeune, Paris, France
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Bukowska-Olech E, Sowińska-Seidler A, Wierzba J, Jamsheer A. SHFLD3 phenotypes caused by 17p13.3 triplication/ duplication encompassing Fingerin (BHLHA9) invariably. Orphanet J Rare Dis 2022; 17:325. [PMID: 36028842 PMCID: PMC9419377 DOI: 10.1186/s13023-022-02480-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 08/13/2022] [Indexed: 11/21/2022] Open
Abstract
Background Split-hand/ foot malformation with long bone deficiency 3 (SHFLD3) is an extremely rare condition associated with duplications located on 17p13.3, which invariably encompasses the BHLHA9 gene. The disease inherits with variable expressivity and significant incomplete penetrance as high as 50%. Results We have detected 17p13.3 locus one-allele triplication in a male proband from family 1 (F1.1), and duplication in a male proband from family 2 (F2.1) applying array comparative genomic hybridization (array CGH). The rearrangements mapped to the following chromosomal regions–arr[GRCh38] 17p13.3(960254–1291856)×4 in F1.1 and arr[GRCh38] 17p13.3(1227482–1302716)×3 in F2.1. The targeted quantitative PCR revealed that the 17p13.3 locus was also duplicated in the second affected member from family 2 (F2.2; brother of F2.1). In the next step, we performed segregation studies using quantitative PCR and revealed that F1.1 inherited the triplication from his healthy father—F1.2, whereas the locus was unremarkable in the mother of F2.1 & F2.2 and the healthy son of F2.1. However, the duplication was present in a healthy daughter of F2.2, an asymptomatic carrier. The breakpoint analysis allowed to define the exact size and span of the duplicated region in Family 2, i.e., 78,948 bp chr17:1225063–1304010 (HG38). Interestingly, all symptomatic carriers from both families presented with variable SHFLD3 phenotype. The involvement of secondary modifying locus could not be excluded, however, the Sanger sequencing screening of BHLHA9 entire coding sequence was unremarkable for both families. Conclusions We have shed light on the one-allele CNV triplication occurrence that should be considered when a higher probe (over duplication range) signal is noted. Second, all SHFLD3 patients were accurately described regarding infrequent limb phenotypes, which were highly variable even when familial. Of note, all symptomatic individuals were males. SHFLD3 still remains a mysterious ultra-rare disease and our findings do not answer crucial questions regarding the disease low penetrance, variable expression and heterogeneity. However, we have presented some clinical and molecular aspects that may be helpful in daily diagnostic routine, both dysmorphological and molecular assessment, of patients affected with SHFLD3. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02480-w.
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Affiliation(s)
| | - Anna Sowińska-Seidler
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Jolanta Wierzba
- Department of Pediatrics and Internal Medicine Nursing, Department of Rare Disorders, Medical University of Gdansk, Gdansk, Poland
| | - Aleksander Jamsheer
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland. .,Centers for Medical Genetics GENESIS, Poznan, Poland.
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The molecular genetics of human appendicular skeleton. Mol Genet Genomics 2022; 297:1195-1214. [PMID: 35907958 DOI: 10.1007/s00438-022-01930-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 07/09/2022] [Indexed: 10/16/2022]
Abstract
Disorders that result from de-arrangement of growth, development and/or differentiation of the appendages (limbs and digit) are collectively called as inherited abnormalities of human appendicular skeleton. The bones of appendicular skeleton have central role in locomotion and movement. The different types of appendicular skeletal abnormalities are well described in the report of "Nosology and Classification of Genetic skeletal disorders: 2019 Revision". In the current article, we intend to present the embryology, developmental pathways, disorders and the molecular genetics of the appendicular skeletal malformations. We mainly focused on the polydactyly, syndactyly, brachydactyly, split-hand-foot malformation and clubfoot disorders. To our knowledge, only nine genes of polydactyly, five genes of split-hand-foot malformation, nine genes for syndactyly, eight genes for brachydactyly and only single gene for clubfoot have been identified to be involved in disease pathophysiology. The current molecular genetic data will help life sciences researchers working on the rare skeletal disorders. Moreover, the aim of present systematic review is to gather the published knowledge on molecular genetics of appendicular skeleton, which would help in genetic counseling and molecular diagnosis.
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Tolezano GC, da Costa SS, Scliar MDO, Fernandes WLM, Otto PA, Bertola DR, Rosenberg C, Vianna-Morgante AM, Krepischi ACV. Investigating Genetic Factors Contributing to Variable Expressivity of Class I 17p13.3 Microduplication. INTERNATIONAL JOURNAL OF MOLECULAR AND CELLULAR MEDICINE 2021; 9:296-306. [PMID: 33688487 PMCID: PMC7936075 DOI: 10.22088/ijmcm.bums.9.4.296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/02/2021] [Indexed: 11/13/2022]
Abstract
17p13.3 microduplications are rare copy number variations (CNVs) associated with variable phenotypes, including facial dysmorphism, developmental delay, intellectual disability, and autism. Typically, when a recognized pathogenic CNV is identified, other genetic factors are not considered. We investigated via whole-exome sequencing the presence of additional variants in four carriers of class I 17p13.3 microduplications. A 730 kb 17p13.3 microduplication was identified in two half-brothers with intellectual disability, but not in a third affected half-brother or blood cells from their normal mother (Family A), thus leading to the hypothesis of maternal germline mosaicism. No additional pathogenic variants were detected in Family A. Two affected siblings carried maternally inherited 450 kb 17p13.3 microduplication (Family B); the three carriers of the microduplication exhibited microcephaly and learning disability/speech impairment of variable degrees. Exome analysis revealed a variant of uncertain significance in RORA, a gene already linked to autism, in the autistic boy; his sister was heterozygous for a CYP1B1 pathogenic variant that could be related to her congenital glaucoma. Besides, both siblings carried a loss-of-function variant in DIP2B, a candidate gene for intellectual disability, which was inherited from their father, who also exhibited learning disability in childhood. In conclusion, additional pathogenic variants were revealed in two affected carriers of class I 17p13.3 microduplication (Family B), probably adding to their phenotypes. These results provided new evidence regarding the contribution of RORA and DIP2B to neurocognitive deficits, and highlighted the importance of full genetic investigation in carriers of CNV syndromes with variable expressivity. Finally, we suggest that microcephaly may be a rare clinical feature also related to the presence of the class I 17p13.3 microduplication.
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Affiliation(s)
- Giovanna Cantini Tolezano
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
| | - Silvia Souza da Costa
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
| | - Marília de Oliveira Scliar
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
| | | | - Paulo Alberto Otto
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
| | - Débora Romeo Bertola
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil .,Instituto da Criança, Hospital das Clínicas, University of São Paulo Medical, São Paulo, SP, Brazil
| | - Carla Rosenberg
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
| | - Angela Maria Vianna-Morgante
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
| | - Ana Cristina Victorino Krepischi
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, SP, Brazil
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The role of ultrasound and genetic counsel in prenatal diagnosis of split hand/foot malformation with long bone deficiency. Taiwan J Obstet Gynecol 2019; 58:574-576. [PMID: 31307755 DOI: 10.1016/j.tjog.2019.05.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2019] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE The aim of the report is to highlight importance of careful ultrasound examination and genetic counsel in case of split hand/foot prenatal diagnosis. Evaluation of the accompanying long bone deficiency indicates that array comparative genomic hybridization (aCGH) should be used. CASE REPORT We present a prenatal diagnosis of split hand/foot malformation with long bone deficiency type 3 (SHFLD3) in a patient suffering from congenital limb anomalies but without previous molecular diagnosis. Genetic consultation and prenatal testing were offered. While karyotype was normal, aCGH revealed microduplication in locus 17p33.3. Microarray analysis was carried out also in pregnant patient and her asymptomatic mother and gave positive results on both. CONCLUSION Prenatal diagnosis of SHFLD3 either imaging or cytogenetic is possible. Both methods should be used to make a correct diagnosis. Due to reduced penetrance of SHFLD3 not all individuals carrying microduplication present clinical findings. Therefore, pedigree analysis and genetic counsel is important for whole family and not only for affected members. Advances in genetics may allow to establish exact diagnosis in previously undiagnosed patients.
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Paththinige CS, Sirisena ND, Escande F, Manouvrier S, Petit F, Dissanayake VHW. Split hand/foot malformation with long bone deficiency associated with BHLHA9 gene duplication: a case report and review of literature. BMC MEDICAL GENETICS 2019; 20:108. [PMID: 31200655 PMCID: PMC6570964 DOI: 10.1186/s12881-019-0839-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 06/03/2019] [Indexed: 12/11/2022]
Abstract
Background Split hand/foot malformation (SHFM) is a group of congenital skeletal disorders which may occur either as an isolated abnormality or in syndromic forms with extra-limb manifestations. Chromosomal micro-duplication or micro-triplication involving 17p13.3 region has been described as the most common cause of split hand/foot malformation with long bone deficiency (SHFLD) in several different Caucasian and Asian populations. Gene dosage effect of the extra copies of BHLHA9 gene at this locus has been implicated in the pathogenesis of SHFLD. Case presentation The proband was a female child born to non-consanguineous parents. She was referred for genetic evaluation of bilateral asymmetric ectrodactyly involving both hands and right foot along with right tibial hemimelia. The right foot had fixed clubfoot deformity with only 2 toes. The mother had bilateral ectrodactyly involving both hands, but the rest of the upper limbs and both lower limbs were normal. Neither of them had any other congenital malformations or neurodevelopmental abnormalities. Genetic testing for rearrangement of BHLHA9 gene by quantitative polymerase chain reaction confirmed the duplication of the BHLHA9 gene in both the proband and the mother. Conclusions We report the first Sri Lankan family with genetic diagnosis of BHLHA9 duplication causing SHFLD. This report along with the previously reported cases corroborate the possible etiopathogenic role of BHLHA9 gene dosage imbalances in SHFM and SHFLD across different populations.
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Affiliation(s)
- Chamara Sampath Paththinige
- Human Genetics Unit, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo, 00800, Sri Lanka. .,Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, Anuradhapura, 50008, Sri Lanka.
| | | | - Fabienne Escande
- Laboratoire de Biochimie et Oncologie Moléculaire, CHU Lille, F-59000, Lille, France
| | - Sylvie Manouvrier
- Clinique de Génétique Guy Fontaine, CHU Lille, F-59000, Lille, France
| | - Florence Petit
- Clinique de Génétique Guy Fontaine, CHU Lille, F-59000, Lille, France
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