There is a wide variety of hereditary and non-hereditary bone dysplasias, many with unique radiographic findings. Hereditary bony dysplasias include osteopoikilosis, osteopathia striata, osteopetrosis, progressive diaphyseal dysplasia, hereditary multiple diaphyseal sclerosis and pyknodysostosis. Non-hereditary dysplasias include melorheostosis, intramedullary osteosclerosis and overlap syndromes. Although many of these dysplasias are uncommon, radiologists should be familiar with their genetic, clinical and imaging findings to allow for differentiation from acquired causes of bony sclerosis. We present an overview of hereditary and non-hereditary bony dysplasias with focus on the pathogenesis, clinical and radiographic findings of each disorder.

BackgroundWerner syndrome (WS) is an autosomal recessive progeroid syndrome caused by variants in WRN. The International Registry of Werner Syndrome has identified biallelic pathogenic variants in 179/188 cases of classical WS. In the remaining nine cases, only one heterozygous pathogenic variant has been identified.MethodsTargeted long-read sequencing (T-LRS) on an Oxford Nanopore platform was used to search for a second pathogenic variant in WRN. Previously, T-LRS was successfully used to identify missing variants and analyse complex rearrangements.ResultsWe identified a second pathogenic variant in eight of nine unsolved WS cases. In five cases, T-LRS identified intronic splice variants that were confirmed by either RT-PCR or exon trapping to affect splicing; in one case, T-LRS identified a 339 kbp deletion, and in two cases, pathogenic missense variants. Phasing of long reads predicted all newly identified variants were on a different haplotype than the previously known variant. Finally, in one case, RT-PCR previously identified skipping of exon 20; however, T-LRS did not detect a pathogenic DNA sequence variant.ConclusionT-LRS is an effective method for identifying missing pathogenic variants. Although limitations with computational prediction algorithms can hinder the interpretation of variants, T-LRS is particularly effective in identifying intronic variants.

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Cartap is a pesticide commonly used to control weevil and caterpillars. It is an analogue of nereistoxin, a neurotoxic substance isolated from the marine annelid Lumbriconereis heteropoda. It causes neuromuscular blockade. Poisoning with cartap is very rare and not yet reported from India. We report a 35-year-old lady with cartap poisoning who presented with nausea, vomiting, and dyspnea. She improved with N-acetyl cysteine and symptomatic management.

We describe three male individuals from a consanguineous south Indian family affected with the multiple pterygium syndrome (Escobar syndrome). Common clinical features included short stature, multiple pterygium, skeletal anomalies, and normal intelligence. The first report of this condition was made in 1902 from this same place (Pondicherry) and the disease received its present popular name Escobar syndrome in 1982. The genetic defect for this condition was identified in 2006 as mutation in the fetal acetylcholine receptor.