Pediatric Musculoskeletal Radiologist in India – Challenges and Opportunities

Pediatric musculoskeletal (MSK) radiology is a relatively under developed superspeciality in India. It encompasses many different entities such as bone tumors, congenital bone dysplasias, endocrine and metabolic bone disorders, and trauma. We conducted a survey of Indian pediatricians and radiologists to assess to ascertain their view regarding the role of pediatric MSK radiologist. In this article, we discuss the challenges, opportunities, and importance of pediatric MSK radiologist in India.

The results of the survey among the parents of patients with achondroplasia on the role of vosoritide therapy

Introduction Achondroplasia (ACP) is a common skeletal dysplasia. Vozoritide is the first drug that has an effect on the pathogenesis of impaired enchondral growth in achondroplasia. Clinical trials of the second and third phases have shown its effectiveness according to the latest literature data presented. After providing scientifically grounded information, a questionnaire was completed by parents of children with ACP to have their opinion before the introduction of the drug into medical practice. Materials and methods The survey was conducted on June 21-24, 2021 at the Ilizarov Center supported by the patient’s organization Small People Support Center for Patients with Achondroplasia and Other Bone Dysplasias and Their Families. The questionnaire included 5 questions, compiled by the first author of this study. 65 completed questionnaires were received for the analysis. Results and discussion The overwhelming majority of parents have confidence in the use of vozoritide as a means of achieving targeted growth which may allow to avoid surgical treatment. However, the parallel use of this drug and surgical treatment for incomplete growth of a child is not excluded if the growth graphs show that the required parameters have not been achieved by the time the growth zones are closed. Despite the fact that at present only the influence of vozoritide on the growth of a child with ACP has been reliably proven, parents feel confident with the information about the possible effect of the drug on other problems associated with impaired enchondral growth, and are ready to start therapy at an earlier age and for a longer period. Parents do not oppose the pharmacological treatment to surgical treatment. Vozoritide is seen as the main component of treatment, and surgery as a complementary one that follows (if necessary). This reasonable combination increases the parents' confidence in the predicted favorable treatment outcome.

Estimation of the carrier frequencies and proportions of potential patients by detecting causative gene variants associated with autosomal recessive bone dysplasia using a whole-genome reference panel of Japanese individuals

Bone dysplasias are a group of rare hereditary diseases, with up to 436 disease types. Perinatal diagnosis is clinically important for adequate personalized management and counseling. There are no reports focused on pathogenic variants of bone dysplasias in the general population. In this study, we focused on autosomal recessive bone dysplasias. We identified pathogenic variants using whole-genome reference panel data from 3552 Japanese individuals. For the first time, we were able to estimate the carrier frequencies and the proportions of potential patients. For autosomal recessive bone dysplasias, we detected 198 pathogenic variants of 54 causative genes. We estimated the variant carrier frequencies and the proportions of potential patients with variants associated with four clinically important bone dysplasias: osteogenesis imperfecta (OI), hypophosphatasia (HPP), asphyxiating thoracic dysplasia (ATD), and Ellis–van Creveld syndrome (EvC). The proportions of potential patients with OI, ATD, and EvC based on pathogenic variants classified as “pathogenic” and “likely pathogenic” by InterVar were closer to the reported incidence rates in Japanese subjects. Furthermore, the proportions of potential patients with HPP variants classified as “pathogenic” and “likely pathogenic” in InterVar and “pathogenic” in ClinVar were closer to the reported incidence rates. For bone dysplasia, the findings of this study will provide a better understanding of the variant types and frequencies in the Japanese general population, and should be useful for clinical diagnosis, genetic counseling, and personalized medicine.

Characteristic diagnostic clues of metatropic dysplasia: The lumbothoracic humpback with dumbbell appearance of the long bones

Metatropic dysplasia (MD) is a rare skeletal dysplasia associated with heterozygous mutations in the TRPV4 gene. We describe a 28-month-old boy with knock-knees referred for metabolic investigation suspected of carrying vitamin D-resistant rickets. He has received regular vitamin D prophylaxis at the usual dose. Laboratory investigations revealed normal values for calcium, phosphorus and alkaline phosphatase. He was short (-3.5 SDS), his mental development was normal, and he started to walk at the age of 22 months. The diagnostic clue for the diagnosis of metatropic dysplasia was the presence of the hump back in the upper lumbar and lower thoracic vertebrae, in addition to a long and narrow chest. An X-ray survey of the skeleton revealed platyspondyly, dysplastic metaphyses with dumbbell appearance of the long bones, kyphoscoliosis, and narrow and elongated thorax with short ribs. This is the first patient with MD in the Republic of Macedonia. Knock-knees were the cause of his referral, as a peculiarity of his phenotype. The very presence of the hump back, and the dumbbell appearance of the long bones distinguished the MD from other bone dysplasias with similar characteristics. We believe that the presence of those two features can shorten the path to accurate diagnosis in the crowded field of overlapping skeletal dysplasias. The diagnosis of MD in this patient was further confirmed by the discovery of the mutation c.2396C>T; p.Pro799Leu (P799L) of the TRPV4 gene.

Polytopic Dysostoses

This chapter further discusses bone dysplasias and includes discussion on campomelic dysplasia, cousin dysplasia, spondylo-megaepiphyseal-metaphyseal dysplasia, cleidocranial dysplasia, Yunis-Varon syndrome, CDAGS, nail-patella syndrome, ischio-pubic-patellar dysplasia, ischiospinal dysostosis, and cerebro-costo-mandibular syndrome. Each discussion includes major radiographic features, major clinical findings, genetics, major differential diagnoses, and a bibliography.