Blended Phenotype of Pelger-Huet Anomaly with Osteochondroma and Autosomal Recessive Deafness with Enlarged Vestibular Aqueduct

Pelger-Huet anomaly (PHA) is a benign hematological anomaly that is characterized by impaired lobulation of neutrophils with a coarse nuclear chromatin. Skeletal abnormalities may accompany this anomaly. Autosomal recessive deafness-4 (DFNB4) with enlarged vestibular aqueduct (EVA) comprises a phenotypic spectrum of sensorineural hearing loss (SNHL). We report a case with SNHL, multiple skeletal anomalies including osteochondroma, developmental delay, and PHA. Molecular studies revealed a heterozygous pathogenic variant in the <i>LBR</i> gene and a homozygous likely pathogenic variant in the <i>SLC26A4</i> gene. Due to these 2 variants, he was diagnosed with PHA and DFNB4 with EVA. If goiter develops, DFNB4 with EVA is named Pendred syndrome (PDS), so the patient will be followed up for this condition, and in the current literature, there is no case with PDS and PHA co-existence either. PHA may be accompanied by multiple skeletal abnormalities. In our case, there is also concomitance with osteochondroma. Although these are independent and distinct diagnoses, we present this case due to the concomitance of these situations.

Phenotyping Zebrafish Mutant Models to Assess Candidate Genes Associated with Aortic Aneurysm

(1) Background: Whole Exome Sequencing of patients with thoracic aortic aneurysm often identifies “Variants of Uncertain Significance” (VUS), leading to uncertainty in clinical management. We assess a novel mechanism for potential routine assessment of these genes in TAA patients. Zebrafish are increasingly used as experimental models of disease. Advantages include low cost, rapid maturation, and physical transparency, permitting direct microscopic assessment. (2) Methods: Zebrafish loss of function mutations were generated using a CRISPRC/CAS9 approach for EMILIN1 and MIB1 genes similar to VUSs identified in clinical testing. Additionally, “positive control” mutants were constructed for known deleterious variants in FBN1 (Marfan’s) and COL1A2, COL5A1, COL5A2 (Ehlers-Danlos). Zebrafish embryos were followed to six days post-fertilization. Embryos were studied by brightfield and confocal microscopy to ascertain any vascular, cardiac, and skeletal abnormalities. (3) Results: A dramatic pattern of cardiac, cerebral, aortic, and skeletal abnormalities was identified for the known pathogenic FBN1 and COL1A2, COL5A1, and COL5A2 mutants, as well as for the EMILIN1 and MIB1 mutants of prior unknown significance. Visualized abnormalities included hemorrhage (peri-aortic and cranial), cardiomegaly, reduced diameter of the aorta and intersegmental vessels, lower aortic cell counts, and scoliosis (often extremely severe). (4) Conclusion: This pilot study suggests that candidate genes arising in clinical practice may be rapidly assessed via zebrafish mutants—thus permitting evidence-based decisions about pathogenicity. Thus, years-long delays to clinically demonstrate pathogenicity may be obviated. Zebrafish data would represent only one segment of analysis, which would also include frequency of the variant in the general population, in silico genetic analysis, and degree of preservation in phylogeny.

A novel TAB2 mutation detected in a putative case of frontometaphyseal dysplasia

Frontometaphyseal dysplasia (FMD) type 2 is an autosomal dominant disorder characterized by skeletal abnormalities and caused by MAP3K7 mutation. We identified a novel missense mutation in TAB2 associated with FMD in a child with multiple congenital malformations. This case was diagnosed as FMD due to joint contractures and bone deformities. This is the third report of FMD caused by a TAB2 mutation located in the TAK1-binding region.

Epidemiology and Phenotypic Characteristics of Dual Molecular Diagnosis Cases in Skeletal Abnormality

Background Skeletal abnormality is a heterogeneous group of disorders that affects the composition and structure of bone and cartilage. In our previous studies, we have revealed that a substantial proportion of cases with early-onset scoliosis could be explained by monogenic disorders such as Marfan syndrome and Ehlers-Danlos syndrome. More recently complex phenotypes caused by more than one genetic defect (i.e., dual molecular diagnosis) have also been reported in skeletal abnormalities. To explore the molecular epidemiology and phenotypic characteristics of dual diagnosis in skeletal abnormalities, we described cases with dual molecular diagnosis from the Deciphering disorders Involving Scoliosis and COmorbidities (DISCO) study.Results In total, 1108 patients with skeletal abnormality from the DISCO study underwent Exome Sequencing. We identified eight probands with dual molecular diagnosis, including three (0.7%) from individuals with early-onset scoliosis (EOS), three (0.5%) from individuals with short stature, and two (2%) from individuals with congenital hand/foot deformity (CHFA). Other skeletal abnormalities observed in these individuals included bone fracture and interphalangeal joint contracture. All the eight probands have dual diagnosis of two autosomal dominant (AD) diseases. A total of 16 variants in 12 genes were identified. A substantial rate (5 of 10) of the identified causal variants were of de novo origin. The frequently observed molecular diagnoses (observed in more than one patient) include Osteogenesis Imperfecta Type I (COL1A1, MIM:166200), Neurofibromatosis, Type I (NF1, MIM:162200) and Marfan Syndrome (FBN1, MIM:154700). These patients with dual molecular diagnosis often present blended phenotypes of two diseases, which significantly complicate their diagnostic process. Conclusions This study revealed the molecular epidemiology and complex diagnostic odyssey of dual molecular diagnosis through analyzing the clinical traits of skeletal abnormalities in eight patients.

Gollop-Wolfgang Complex: Clinical and Imaging Implications

Gollop-Wolfgang complex is defined as the presence of a distal bifid femur and tibial hemimelia with or without hand ectrodactyly. The condition commonly presents with several skeletal abnormalities and internal organ congenital defects. We hereby report a case with a classical presentation of Gollop-Wolfgang complex.

Congenital and Developmental Abnormalities of the Hand and Wrist

Identification of congenital skeletal abnormalities is complex because of the large variety of individual syndromes and dysplasias that are often difficult to remember. Although a correct diagnosis relies on a combination of clinical, radiologic, and genetic tests, imaging plays an important role in selecting those patients who should be referred for further genetic counseling and expensive genetic tests. In addition to information derived from radiologic analysis of other skeletal elements, radiographs of the hand and wrist may provide particular useful information. In the first part of this article, we provide a guide for a systematic radiologic analysis of the hand and wrist bones that may help characterize congenital and developmental diseases. Special attention is given to the use of correct terminology. In the second part, we discuss typical examples of congenital and developmental diseases involving the hand and wrist, with an emphasis on skeletal dysplasias.