Preaxial polydactyly of the foot: Clinical and genetic implications for the orthopedic practice based on a literature review and 76 patients

Background and purpose — Preaxial polydactyly of the foot is a rare malformation and clinicians are often unfamiliar with the associated malformations and syndromes. In order to give guidelines for diagnostics and referral to a clinical geneticist, we provide an overview of the presentation using a literature review and our own patient population. Patients and methods — The literature review was based on the Human Phenotype Ontology (HPO) project. From the HPO dataset, all phenotypes describing preaxial polydactyly were obtained and related diseases were identified and selected. An overview was generated in a heatmap, in which the phenotypic contribution of 12 anatomical groups to each disease is displayed. Clinical cases were obtained from our hospital database a

Variable expression of subclinical phenotypes instead of reduced penetrance in families with mild triphalangeal thumb phenotypes

Backgroun: 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 thisreport, we describe two families with mild phenotypical presentation Methods: Weperformed a field study for clinical evaluation and sequenced the ZRS for variantsusing Sanger sequencing. Results: In familyI, a novel 165A>G variant in the ZRS(g.156584405A>G, GRCh37/Hg19) was found. Infamily II, we identified a 295T>C variant inthe ZRS (g.156584535T>C, GRCh37/Hg19). Family members of both families who werepresumed to be unaffected shared the variant in the ZRS with affected familymembers, suggesting reduced penetrance of the genotype. However, clinicalexamination of these unaffected family members revealed minor anomalies likebroad thumbs and lack of thumb opposition. As the phenotype in affected patients is remarkably mild, we suggest that theseZRS variants are minimally disruptive for Sonic Hedgehog expression andtherefore 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

Variant type and position predict two distinct limb phenotypes in patients with GLI3-mediated polydactyly syndromes

Introduction: Pathogenic DNA variants in the GLI-Kruppel family member 3 (GLI3) gene are known to cause multiple syndromes: for example, Greig syndrome, preaxial polydactyly-Type 4 (PPD4) and Pallister-Hall syndrome. Out of these, Pallister-Hall is a different entity, but the distinction between Greig syndrome and PPD4 is less evident. Using latent class analysis (LCA), our study aimed to investigate the correlation between reported limb anomalies and the reported GLI3 variants in these GLI3-mediated polydactyly syndromes. We identified two subclasses of limb anomalies that relate to the underlying variant. Methods: Both local and published cases were included for analysis. The presence of individual limb phenotypes was dichotomised and an exploratory LCA was performed. Distribution of phenotypes and genotypes over the classes were explored and subsequently the key predictors of latent class membership were correlated to the different clustered genotypes. Results: 297 cases were identified with 127 different variants in the GLI3 gene. A two-class model was fitted revealing two subgroups of patients with anterior versus posterior anomalies. Posterior anomalies were observed in cases with truncating variants in the activator domain (postaxial polydactyly; hand, OR: 12.7; foot, OR: 33.9). Multivariate analysis supports these results (Beta: 1.467, p=0.013 and Beta: 2.548, p<0.001, respectively). Corpus callosum agenesis was significantly correlated to these variants (OR: 8.8, p<0.001). Conclusion: There are two distinct phenotypes within the GLI3-mediated polydactyly population: Anteriorly and posteriorly orientated. Variants that likely produce haploinsufficiency are associated with anterior phenotypes. Posterior phenotypes are associated with truncating variants in the activator domain. Patients with these truncating variants have a greater risk for corpus callosum anomalies

Congenital Forearm Pseudarthrosis, a Systematic Review for a Treatment Algorithm on a Rare Condition

Background: A congenital forearm pseudarthrosis is a rare condition and is strongly associated with neurofibromatosis type 1. Several surgical techniques are described in the literature, but the most optimal treatment strategy remains unclear. This systematic review aims to develop a treatment algorithm that may aid i

Apert syndrome: the Paris and Rotterdam philosophy

Introduction: Apert syndrome is a rare type of syndromic craniosynostosis. Patients have an explicit phenotype with craniofacial dysmorphologies and severe symmetrical syndactyly of the hands and feet. This review includes background information about the syndrome and several aspects of the treatment. Areas covered: The cause of Apert syndrome is found in unique mutations in the Fibroblast Growth Factors Receptor (FGFR) 2 gene in 99%. It results in cranial suture fusion, craniofacial dysmorphologies and severe symmetrical syndactyly of the hands and feet. Patients with Apert syndrome are at risk for mental retardation, mobility impairment and intracranial hypertension (ICHT). This is the result of a complex interaction between (1) abnormal skull growth, (2) ventriculomegaly, (3) venous outflow obstruction and (4) obstructive sleep apnea (OSA). Mental retardation is mainly determined by the FGFR2 mutation and treatment is directed at protecting the intrinsic potential of neurocognition. Expert Opinion: To prevent ICHT, we prefer an occipital expansion in the first year of life. Screening on ICHT and its underlying causes is necessary at least until the age of ten by means of skull circumference measurements, fundoscopy, optical coherence tomography, MRI and polysomnography. Multicentre studies on long-term outcome are required to validate the rationale of different clinical protocols

Documenting Combined Congenital Upper Limb Anomalies Using the Oberg, Manske, and Tonkin Classification: Implications for Epidemiological Research and Outcome Comparisons

Item does not contain fulltextPURPOSE: Congenital upper limb anomalies (CULAs) exhibit a wide spectrum of phenotypic manifestations. To help the clinician evaluating this variety of CULAs, the Oberg, Manske, and Tonkin (OMT) classification was recently introduced. The OMT classification allows for documentation of combined hand anomalies. However, subsequent epidemiological and validation studies using the OMT scheme commonly registered only the main anomaly per arm. This study illustrates both the deficits of single diagnosis documentation as well as the merits of registering every anomaly for epidemiological research, outcome comparison, and overall applicability of the classification. METHODS: We retrospectively reviewed patients visiting the Erasmus MC - Sophia Children's Hospital between 2012 and 2014. All congenital anomalies of both limbs were classified according to the OMT scheme. The frequency of combined diagnoses as well as recurrent combinations were analyzed. The relation to the coregistered syndromes was studied. RESULTS: We included 746 patients, 79.5% of whom could be documented with a single OMT diagnosis. In 20.5%, a combination of OMT diagnoses was documented. We documented 149 different combinations: 102 were documented once, 47 were documented repeatedly (n = 196); for example, in patients with Greig syndrome. The prevalence of this syndrome was significantly higher in patients with a combination of radial polydactyly, ulnar polydactyly, and/or syndactyly (2.9% vs 33.3% and 60% in patients with 1 vs 2 and 3 diagnoses). CONCLUSIONS: Documentation of combined OMT diagnoses is required in a fifth of the patients. Not doing so will cause loss of phenotypic information and can hamper outcome comparison and epidemiological research. Documentation of combined OMT diagnoses can help to identify subgroups within a population, for example, patients with an underlying syndrome. Last, combined documentation of diagnoses improves flexibility of the classification and thereby better allows universal application. CLINICAL RELEVANCE: Consensus on the application of the OMT classification is critical to achieving the universal adoption of the system by hand surgeons and other medical professionals

Lateral Versus Medial Hallux Excision in Preaxial Polydactyly of the Foot

Contains fulltext : 229261.pdf (Publisher’s version ) (Closed access)BACKGROUND: In preaxial polydactyly of the foot, the choice for excision of the lateral or medial hallux is not straightforward, in particular with proximal phalangeal (type IV) and metatarsal (type VI) duplication, because of anatomical characteristics. We evaluated whether medial or lateral hallux excision gives better outcomes in these duplication types, to help clinical decision making. METHODS: Children with type IV or type VI duplication (n=14, age: 4.4-17.2 years), who were operatively treated by excision of the lateral or medial hallux, were assessed for foot function using plantar pressure measurements and clinical examination. Foot aesthetics were scored by the child, an expert, and 10 laypersons, and additional patient-reported outcome questionnaires were obtained. Outcomes were compared between lateral and medial excision, per duplication type. RESULTS: In type IV duplication (n=11), lateral excision showed a better distribution of peak pressure between the hallux and first metatarsal with significantly lower median first metatarsal peak pressure (P = .008). Lateral excision showed more medial hallux deviation (P = .017). Foot aesthetics were not different between excision sides. In type VI duplication (n=12), lateral excision showed a 59% higher hallux peak pressure, larger medial hallux deviation (P = .004), and more reoperations. Foot aesthetics were scored significantly better after lateral excision by experts and laypersons. CONCLUSIONS: Foot function by virtue of plantar pressure was better after lateral hallux excision in type IV and after medial hallux excision in type VI duplication. Surgeons and laypersons perceived the foot as more normal after lateral excision in type VI, whereas children reported no differences. These outcomes can be used in clinical decision making. LEVEL OF EVIDENCE: Level III, therapeutic, comparative study

A multidisciplinary review of triphalangeal thumb

Contains fulltext : 203356.pdf (publisher's version ) (Open Access)Despite being a rare congenital limb anomaly, triphalangeal thumb is a subject of research in various scientific fields, providing new insights in clinical research and evolutionary biology. The findings of triphalangeal thumb can be predictive for other congenital anomalies as part of an underlying syndrome. Furthermore, triphalangeal thumb is still being used as a model in molecular genetics to study gene regulation by long-range regulatory elements. We present a review that summarizes a number of scientifically relevant topics that involve the triphalangeal thumb phenotype. Future initiatives involving multidisciplinary teams collaborating in the field of triphalangeal thumb research can lead to a better understanding of the pathogenesis and molecular mechanisms of this condition as well as other congenital upper limb anomalies

Recurrence of Dupuytren's contracture: A consensus-based definition

Contains fulltext : 207059.pdf (publisher's version ) (Open Access)[This corrects the article DOI: 10.1371/journal.pone.0164849.]