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Meirizal, Muhammad H, Guntoro BD, Magetsari R. Neglected bilateral triphalangeal of the thumb delta type in adult case: A case report. Int J Surg Case Rep 2024; 114:109087. [PMID: 38016377 PMCID: PMC10711151 DOI: 10.1016/j.ijscr.2023.109087] [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: 10/23/2023] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 11/30/2023] Open
Abstract
INTRODUCTION In rare case, thumb has extra phalanges known as triphalangeal of the thumb (TPT). Patients with TPT can have difficulty doing work/activities that require high precision. Therefore, surgical intervention is essential. This report provides an approach for a patient with TPT. PRESENTATION OF CASE A patient with TPT who underwent removal of extra phalanges and arthrodesis of interphalangeal (IP) joints is presented. The left thumb deviated 25o to ulnar while the contralateral part deviated 15o to radial. X-ray revealed both thumbs had extra delta-shaped middle phalanges. Complete excision of extra phalanges and simple arthrodesis of IP joints with two K-wires in 10° to 15° flexion was performed. Healing process ended without any complications and the patient had an improvement. DISCUSSION Productive-age patients with TPT can have difficulty doing work and activities that require high precision, especially in the non-opposable type of the right hand. Furthermore, the female patient is highly emphasizing the cosmetics of her hand to increase her self-confidence. Therefore, surgical intervention is essential for this patient. We performed complete excision of extra phalanges and simple arthrodesis of IP joints with two K-wires in 10° to 20° flexion. The first K-wire is introduced intramedullary as a primary fixator for longitudinal alignment, and the second wire is inserted obliquely as an anti-rotation wire. Functional outcome was assessed after 6 months post-removal of the wire which gave a satisfying result. CONCLUSION TPT is a rare anomaly which surgical intervention can improve the appearance and the precision of the hand.
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Affiliation(s)
- Meirizal
- Dept. of Orthopedic and Traumatology Sardjito General Hospital, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia.
| | - Hilmi Muhammad
- Dept. of Orthopedic and Traumatology Sardjito General Hospital, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Brahmantyo Danang Guntoro
- Dept. of Orthopedic and Traumatology Sardjito General Hospital, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Rahadyan Magetsari
- Dept. of Orthopedic and Traumatology Sardjito General Hospital, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
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Winge MI, Guéro S, Zavarukhin V, Paavilainen P, Baldrighi C, Kjørup A, Hülsemann W. Ulnar dimelia - a review of 24 cases. J Hand Surg Eur Vol 2023; 48:1126-1135. [PMID: 37684016 PMCID: PMC10785563 DOI: 10.1177/17531934231196418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/03/2023] [Accepted: 08/06/2023] [Indexed: 09/10/2023]
Abstract
Ulnar dimelia is a very rare unilateral congenital upper limb anomaly (CULA) affecting the whole extremity. Treatment remains difficult because of the complexity and multi-level involvement. Twenty-four cases with duplicated ulna, absent radius and polydactyly from seven European centres were reviewed according to a structured list of parameters. At first consultation, median age 8 months (1-178), the shoulder movement was good in 17 patients or poor in six, and the median passive elbow range of motion was 20° (0°-90°). The resting wrist position was flexed in 22/24 patients. Following stretching and splinting, elbow surgery included resection of the lateral proximal ulna in 11 patients and muscle transfers in six to improve passive movement and increase active elbow motion, respectively. Tendon transfers were performed in eight wrists and a pollicization or pseudo-pollicization in 23 patients. Overall, patients demonstrate acceptable function postoperatively. Guidelines for treatment of this severe CULA are presented.Level of evidence: IV.
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Affiliation(s)
- Mona I. Winge
- Division of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway
| | | | - Vladimir Zavarukhin
- Saint Petersburg State University Hospital, Vasilievsky island, Saint-Petersburg, Russia
| | | | | | | | - Wiebke Hülsemann
- Children`s Hospital Wilhelmstift, Handsurgery Department, Hamburg, Germany
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Tiourin E, Sharpe F, Kalina S, Leis AR. Surgical Reconstruction for the Triphalangeal Thumb. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2023; 11:e5379. [PMID: 37928630 PMCID: PMC10624463 DOI: 10.1097/gox.0000000000005379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 09/06/2023] [Indexed: 11/07/2023]
Abstract
The triphalangeal thumb poses a complex reconstructive challenge to the congenital hand surgeon due to its rarity and variable anatomy. We discuss the available evidence, reporting clinical characteristics and outcomes of surgical reconstructive procedures of triphalangeal thumb alongside a representative case. The congenital hand surgeon must approach each patient with triphalangeal thumb individually to optimize the use of available tissues to maximize functional and aesthetic outcomes.
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Affiliation(s)
- Ekaterina Tiourin
- From the Department of Plastic Surgery, University of California, Irvine Medical Center, Orange, Calif
| | - Frances Sharpe
- SCPM Southern California Permanente Medical Group, Fontana, Calif
| | - Sharon Kalina
- SCPM Southern California Permanente Medical Group, Fontana, Calif
| | - Amber R Leis
- From the Department of Plastic Surgery, University of California, Irvine Medical Center, Orange, Calif
- Division of Plastic Surgery, Children's Hospital Orange County, Orange, Calif
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Álvarez LFG, Tenorio-Castaño J, Poletta FA, Santos-Simarro F, Arias P, Gallego N, Orioli IM, Mundlos S, Castilla EE, Martínez-Glez V, Martínez-Frías ML, Ruiz-Pérez VL, Nevado J, Lapunzina P. A large, ten-generation family with autosomal dominant preaxial polydactyly/triphalangeal thumb: Historical, clinical, genealogical, and molecular studies. Am J Med Genet A 2023; 191:100-107. [PMID: 36308343 DOI: 10.1002/ajmg.a.62994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 07/05/2022] [Accepted: 08/19/2022] [Indexed: 12/14/2022]
Abstract
We present a large, ten-generation family of 273 individuals with 84 people having preaxial polydactyly/triphalangeal thumb due to a pathogenic variant in the zone of polarizing activity regulatory sequence (ZRS) within the exon 5 of LMBR1. The causative change maps to position 396 of the ZRS, located at position c.423 + 4909C > T (chr7:156791480; hg38; LMBR1 ENST00000353442.10; rs606231153 NG_009240.2) in the intron 5 of LMBR1. The first affected individual with the disorder was traced back to mid-1700, when some settlers and workers established in Cervera de Buitrago, a small village about 82 km North to Madrid. Clinical and radiological studies of most of the affected members have been performed for 42 years (follow-up of the family by LFGA). Molecular studies have confirmed a pathogenic variant in the ZRS that segregates in this family. To the best of our knowledge, this is the largest family with preaxial polydactyly/triphalangeal thumb reported so far.
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Affiliation(s)
| | - Jair Tenorio-Castaño
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
- INGEMM-Idipaz, Institute of Medical and Molecular Genetics, Madrid, Spain
- ITHACA, European Reference Network, Brussels, Belgium
| | - Fernando A Poletta
- ECLAMC at CEMIC (Center for Medical Education and Clinical Research) and CONICET (National Council for Scientific and Technical Investigation), Buenos Aires, Argentina
- ECLAMC (Latin American Collaborative Study of Congenital Malformations) at INAGEMP (National Institute of Population Medical Genetics), Rio de Janeiro, Brazil
- Department of Genetics, Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernando Santos-Simarro
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
- INGEMM-Idipaz, Institute of Medical and Molecular Genetics, Madrid, Spain
- ITHACA, European Reference Network, Brussels, Belgium
| | - Pedro Arias
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
- INGEMM-Idipaz, Institute of Medical and Molecular Genetics, Madrid, Spain
| | - Natalia Gallego
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
- INGEMM-Idipaz, Institute of Medical and Molecular Genetics, Madrid, Spain
- ITHACA, European Reference Network, Brussels, Belgium
| | - Iêda Maria Orioli
- ECLAMC at CEMIC (Center for Medical Education and Clinical Research) and CONICET (National Council for Scientific and Technical Investigation), Buenos Aires, Argentina
- ECLAMC (Latin American Collaborative Study of Congenital Malformations) at INAGEMP (National Institute of Population Medical Genetics), Rio de Janeiro, Brazil
- Department of Genetics, Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Stefan Mundlos
- Institute of Medical and Human Genetics, Charité Universitätsmedizin, Berlin, Germany
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Eduardo E Castilla
- ECLAMC at CEMIC (Center for Medical Education and Clinical Research) and CONICET (National Council for Scientific and Technical Investigation), Buenos Aires, Argentina
- ECLAMC (Latin American Collaborative Study of Congenital Malformations) at INAGEMP (National Institute of Population Medical Genetics), Rio de Janeiro, Brazil
- Department of Genetics, Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Víctor Martínez-Glez
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
- INGEMM-Idipaz, Institute of Medical and Molecular Genetics, Madrid, Spain
- ITHACA, European Reference Network, Brussels, Belgium
| | | | - Víctor L Ruiz-Pérez
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
- ITHACA, European Reference Network, Brussels, Belgium
- Instituto de Investigaciones Biomédicas Alberto Sols, IIB-UAM, Madrid, Spain
| | - Julián Nevado
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
- INGEMM-Idipaz, Institute of Medical and Molecular Genetics, Madrid, Spain
- ITHACA, European Reference Network, Brussels, Belgium
| | - Pablo Lapunzina
- CIBERER, Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain
- INGEMM-Idipaz, Institute of Medical and Molecular Genetics, Madrid, Spain
- ITHACA, European Reference Network, Brussels, Belgium
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The pZRS non-coding regulatory mutation resulting in triphalangeal thumb-polysyndactyly syndrome changes the pattern of local interactions. Mol Genet Genomics 2022; 297:1343-1352. [PMID: 35821352 DOI: 10.1007/s00438-022-01921-2] [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: 11/08/2021] [Accepted: 06/18/2022] [Indexed: 10/17/2022]
Abstract
Herein, we report on a large Polish family presenting with a classical triphalangeal thumb-polysyndactyly syndrome (TPT-PS). This rare congenital limb anomaly is generally caused by microduplications encompassing the Sonic Hedgehog (SHH) limb enhancer, termed the zone of polarizing activity (ZPA) regulatory sequence (ZRS). Recently, a pathogenic variant in the pre-ZRS (pZRS), a conserved sequence located near the ZRS, has been described in a TPT-PS Dutch family. We performed targeted ZRS sequencing, array comparative genomic hybridization, and whole-exome sequencing. Next, we sequenced the recently described pZRS region. Finally, we performed a circular chromatin conformation capture-sequencing (4C-seq) assay on skin fibroblasts of one affected family member and control samples to examine potential alterations in the SHH regulatory domain and functionally characterize the identified variant. We found that all affected individuals shared a recently identified pathogenic point mutation in the pZRS region: NC_000007.14:g.156792782C>G (GRCh38/hg38), which is the same as in the Dutch family. The results of 4C-seq experiments revealed increased interactions within the whole SHH regulatory domain (SHH-LMBR1 TAD) in the patient compared to controls. Our study expands the number of TPT-PS families carrying a pathogenic alteration of the pZRS and underlines the importance of routine pZRS sequencing in the genetic diagnostics of patients with TPT-PS or similar phenotypes. The pathogenic mutation causative for TPT-PS in our patient gave rise to increased interactions within the SHH regulatory domain in yet unknown mechanism.
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Abstract
» Surgical timing for pediatric trigger thumb treatment is controversial for numerous reasons including the potential for spontaneous resolution, the possibility of bilateral involvement, and anesthesia concerns regarding the developing brain. Hence, a reasonable approach is to delay the surgical procedure until the patient is ≥3 years of age. » Preaxial polydactyly is usually unilateral and sporadic, with the most common reconstruction method consisting of excision of the diminutive thumb with preservation and soft-tissue reconstruction of the dominant thumb. The surgical procedure is typically performed around the patient age of 1 year to decrease the risks of anesthesia but allow reconstruction prior to the development of a tip-to-tip pinch. » Triphalangeal thumb and thumb hypoplasia are often found in the setting of systemic anomalies such as Holt-Oram syndrome, thrombocytopenia absent radius syndrome, Fanconi anemia, VACTERL (vertebral anomalies, anal atresia, cardiac anomalies, tracheoesophageal fistula, renal defects, and limb anomalies), and/or Blackfan-Diamond anemia. As such, patients should receive adequate workup for these entities. A surgical procedure should be performed only once patients have been medically cleared. » The status of the carpometacarpal joint in thumb hypoplasia determines whether reconstruction with first web space deepening, collateral ligament stabilization, and opponensplasty compared with index pollicization is performed.
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Affiliation(s)
- Jenny Lee Nguyen
- Texas Children's Hospital, Houston, Texas.,Department of Plastic Surgery, Baylor College of Medicine, Houston, Texas
| | - Christine A Ho
- Scottish Rite for Children, Dallas, Texas.,Department of Orthopaedic Surgery, Children's Health Dallas, Dallas, Texas.,University of Texas at Southwestern School of Medicine, Dallas, Texas
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Spatial regulation by multiple Gremlin1 enhancers provides digit development with cis-regulatory robustness and evolutionary plasticity. Nat Commun 2021; 12:5557. [PMID: 34548488 PMCID: PMC8455560 DOI: 10.1038/s41467-021-25810-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 09/02/2021] [Indexed: 11/17/2022] Open
Abstract
Precise cis-regulatory control of gene expression is essential for normal embryogenesis and tissue development. The BMP antagonist Gremlin1 (Grem1) is a key node in the signalling system that coordinately controls limb bud development. Here, we use mouse reverse genetics to identify the enhancers in the Grem1 genomic landscape and the underlying cis-regulatory logics that orchestrate the spatio-temporal Grem1 expression dynamics during limb bud development. We establish that transcript levels are controlled in an additive manner while spatial regulation requires synergistic interactions among multiple enhancers. Disrupting these interactions shows that altered spatial regulation rather than reduced Grem1 transcript levels prefigures digit fusions and loss. Two of the enhancers are evolutionary ancient and highly conserved from basal fishes to mammals. Analysing these enhancers from different species reveal the substantial spatial plasticity in Grem1 regulation in tetrapods and basal fishes, which provides insights into the fin-to-limb transition and evolutionary diversification of pentadactyl limbs. The BMP antagonist Gremlin1 balances BMP and SHH signalling, endowing limb bud development with robustness. Here, the authors identify enhancers controlling Grem1 levels in an additive, and spatial regulation in a synergistic manner, providing digit patterning with cis-regulatory robustness and evolutionary plasticity.
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The importance of a lifeboat-median artery forearm flap in Goldenhar Syndrome. EUROPEAN JOURNAL OF PLASTIC SURGERY 2021. [DOI: 10.1007/s00238-021-01877-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractWe present a case of a 32-year-old male with left-sided Goldenhar Syndrome and delta phalanx of the thumb, who was offered free tissue transfer from the forearm to address an intra-oral soft tissue deficiency. Despite the presence of appropriately developed right radial artery, used in previous facial reconstruction, the left radial artery occurred to be hypoplastic. He ultimately underwent free flap transfer based on the anomalous persistent left median artery. We suggest that in face of an unusual hand anatomy, flexible flap creation techniques that allow a lifeboat strategy of adjusting flap design should be considered preoperatively. Level of evidence: Level V, therapeutic study.
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Zhang SJ, Lin HB, Jiang QX, He SZ, Lyu GR. Prenatal diagnosis of triphalangeal thumb-polysyndactyly syndrome by ultrasonography combined with genetic testing: A case report. World J Clin Cases 2021; 9:6832-6838. [PMID: 34447832 PMCID: PMC8362503 DOI: 10.12998/wjcc.v9.i23.6832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/04/2021] [Accepted: 06/16/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Triphalangeal thumb-polysyndactyly syndrome (TPT-PS) is a rare type of congenital limb deformity, and most studies focus on the genetics. Case reports of the sonographic characteristics of TPT-PS during pregnancy are rare.
CASE SUMMARY A 30-year-old woman (G3P1) who had pregnancies with TPT-PS fetuses is presented. The possibility of TPT-PS was shown by ultrasound performed at the 19th wk of pregnancy, featuring hands with six metacarpals, an extra digit at the 5th finger side, and an abnormally widened thumb. Whole-exome sequencing was subsequently conducted. The results showed that exons 1-17 of the LMBR1 gene had a heterozygous duplication, with a length of approximately 253 kb.
CONCLUSION We suggest prenatal ultrasound examination combined with genetic testing to diagnose TPT-PS accurately and to help clinicians and patients make decisions.
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Affiliation(s)
- Shi-Jie Zhang
- Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou 362000, Fujian Province, China
| | - Hai-Bin Lin
- Department of Ultrasound, Jinjiang Municipal Hospital, Quanzhou 362000, Fujian Province, China
| | - Qiu-Xia Jiang
- Department of Ultrasound, Quanzhou Women’s and Children’s Hospital, Quanzhou 362000, Fujian Province, China
- Collaborative Innovation Center for Maternal and Infant Health Service, Application Technology of Education Ministry, Quanzhou Medical College, Quanzhou 362000, Fujian Province, China
| | - Shao-Zheng He
- Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou 362000, Fujian Province, China
| | - Guo-Rong Lyu
- Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou 362000, Fujian Province, China
- Department of Ultrasound, Jinjiang Municipal Hospital, Quanzhou 362000, Fujian Province, China
- Department of Ultrasound, Quanzhou Women’s and Children’s Hospital, Quanzhou 362000, Fujian Province, China
- Collaborative Innovation Center for Maternal and Infant Health Service, Application Technology of Education Ministry, Quanzhou Medical College, Quanzhou 362000, Fujian Province, China
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Xu J, Wu J, Teng X, Cai L, Yuan H, Chen X, Hu M, Wang X, Jiang N, Chen H. Large duplication in LMBR1 gene in a large Chinese pedigree with triphalangeal thumb polysyndactyly syndrome. Am J Med Genet A 2020; 182:2117-2123. [PMID: 32662247 DOI: 10.1002/ajmg.a.61757] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 04/30/2020] [Accepted: 05/28/2020] [Indexed: 12/18/2022]
Abstract
Polydactyly and syndactyly are digital abnormalities in limb-associated birth defects usually caused by genetic disorders. In this study, a five-generation Chinese pedigree was found with triphalangeal thumb polysyndactyly syndrome (TPTPS), showing an autosomal dominant pattern of inheritance. We utilized linkage analysis and whole genome sequencing (WGS) for the genetic diagnosis of this pedigree. Linkage analysis was performed using a genome-wide single nucleotide polymorphism (SNP) chip and three genomic regions were identified in chromosomes 2, 6, and 7 with significant linkage signals. WGS discovered a copy number variation (CNV) mutation caused by a large duplication region at the tail of chromosome 7 located in exons 1-5 of the LMBR1 gene, including the zone of polarizing activity regulatory sequence (ZRS), with a length of approximately 180 kb. A real-time polymerase chain reaction (PCR) assay confirmed the duplication. The findings of our study supported the notion that large duplications including the ZRS caused TPTPS. Our study showed that linkage analysis in combination with WGS could successfully identify the disease locus and causative mutation in TPTPS, which could help elucidate the molecular mechanisms and genotype-phenotype correlations in polydactyly.
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Affiliation(s)
- Jihai Xu
- Department of Hand Surgery, Ningbo No. 6 Hospital, Ningbo, China
| | - Jing Wu
- Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaofeng Teng
- Department of Hand Surgery, Ningbo No. 6 Hospital, Ningbo, China
| | - Libing Cai
- Department of Hand Surgery, Ningbo No. 6 Hospital, Ningbo, China
| | - Huizong Yuan
- Department of Hand Surgery, Ningbo No. 6 Hospital, Ningbo, China
| | - Xiaokun Chen
- Department of Orthopedic Trauma, Peking University People Hospital, Beijing, China
| | - Mu Hu
- Department of Orthopedics, Ruijin Hospital North, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Xin Wang
- Department of Hand Surgery, Ningbo No. 6 Hospital, Ningbo, China
| | - Ning Jiang
- Department of Biostatistics and Computational Biology, SKLG, School of Life Sciences, Fudan University, Shanghai, China
| | - Hong Chen
- Department of Hand Surgery, Ningbo No. 6 Hospital, Ningbo, China
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Potuijt JWP, Hoogeboom J, de Graaff E, van Nieuwenhoven CA, Galjaard RJH. Variable expression of subclinical phenotypes instead of reduced penetrance in families with mild triphalangeal thumb phenotypes. J Med Genet 2020; 57:660-663. [PMID: 32179704 PMCID: PMC7525795 DOI: 10.1136/jmedgenet-2019-106685] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/18/2020] [Accepted: 02/21/2020] [Indexed: 12/21/2022]
Abstract
Background The of zone of polarizing activity regulatory sequence (ZRS) is a regulatory element residing in intron 5 of LMBR1 and regulates Sonic Hedgehog expression in the limb bud. Variants in the ZRS are generally fully penetrant and can cause triphalangeal thumb (TPT) and polydactyly in affected families. Objective In this report, we describe two families with mild phenotypical presentation. Methods We performed a field study for clinical evaluation and sequenced the ZRS for variantsusing Sanger sequencing. Results In family I, a novel 165A>G variant in the ZRS (g.156584405A>G, GRCh37/Hg19) was found. In family II, we identified a 295T>C variant in the ZRS (g.156584535T>C, GRCh37/Hg19). Family members of both families who were presumed to be unaffected shared the variant in the ZRS with affected family members, suggesting reduced penetrance of the genotype. However, clinical examination of these unaffected family members revealed minor anomalies like broad thumbs and lack of thumb opposition. As the phenotype in affected patients is remarkably mild, we suggest that these ZRS variants are minimally disruptive for Sonic Hedgehog expression and therefore can result in subclinical phenotypes. Conclusion Our study underlines the importance of accurate clinical examination and appropriate genetic counselling in families with mild cases of TPT.
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Affiliation(s)
- Jacob W P Potuijt
- Plastic, Reconstructive and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jeannette Hoogeboom
- Clinical Genetics, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Esther de Graaff
- Division of Cell Biology, Neurobiology and Biophysics, Utrecht University, Utrecht, Utrecht, The Netherlands
| | | | - Robert Jan H Galjaard
- Clinical Genetics, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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