Osteogenesis imperfecta (OI), or brittle bone disease, is a genetically inherited connective tissue syndrome that manifests through autosomal dominant or recessive patterns. We present an unusual case involving three siblings with the same father but different mothers. The patients had extremely short stature, recurrent fractures, and varying degrees of severity of OI, in addition to distinctive features such as blue sclera and dentinogenesis imperfecta. The radiographic skeletal surveys revealed the characteristic features of OI in all three siblings. The patients exhibited Wormian bones, multiple fractures with callus formation, bowing of the long bones, accordion ribs, platyspondyly, and kyphoscoliosis. The patients were admitted for inpatient administration of two doses of intravenous zoledronic acid, allowing for monitoring of potential adverse effects. At the 7-month follow-up, the patients reported a reduction in fractures and a notable improvement in their ability to perform daily activities, including the capacity to sit without assistance. The patients did not experience any significant adverse effects from the zoledronic acid. Radiology is vital for diagnosing OI as it highlights the unique skeletal patterns, assists in identifying the specific OI phenotype, and evaluates the severity, particularly when genetic testing is inaccessible.

Cleidocranial dysplasia is a congenital malformation syndrome characterized by skeletal and dental abnormalities as well as distinctive craniofacial features. Most previous reports have relied on two-dimensional radiographs, and no comprehensive three-dimensional investigations have been conducted. This study aimed to provide a detailed overview of craniofacial features in patients with cleidocranial dysplasia using computed tomography. Craniofacial characteristics of 11 Japanese patients were assessed using three-dimensional computed tomography reconstructions. Qualitative evaluations were performed across three regions: cranial, nasomaxillary complex, and mandibular. In the cranial region, all patients presented Wormian bones and hypoplastic mastoid processes. In the nasomaxillary complex, hypoplastic nasal bones, atypical piriform aperture contours, and discontinuous or downward-bent zygomatic arches were frequently observed. In the mandibular region, atypical sigmoid notch morphology, nearly parallel-sided ascending rami, and abnormally rounded mandibular angles were identified. Novel findings included aplastic/hypoplastic styloid processes, thin-appearing orbital walls, downward displacement of the temporal process of the maxillary bone, and atypical coronoid process morphology. Bilateral expression of all craniofacial traits was also newly confirmed. To our knowledge, this is the first comprehensive three-dimensional study of craniofacial morphology in cleidocranial dysplasia. These observations provide new insights into the pathophysiology and developmental mechanisms underlying craniofacial anomalies in affected patients.

Background: Type I collagen is the most abundant protein of the extracellular matrix. Pathogenic variants in COL1A1 or COL1A2 are classically associated with osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS). An emerging clinical entity-COL1-related overlap disorder-encompasses individuals exhibiting phenotypic features of both conditions. Methods: We report a 55-year-old male presenting with disproportionate short stature, grayish-blue sclerae, multiple fractures, long bone deformities, joint hypermobility, and atrophic surgical scarring. The patient also had long-standing, untreated childhood-onset hypopituitarism. Imaging studies revealed numerous prior fractures, bowing of forearm bones, and multiple Wormian bones. Results: Genetic testing confirmed a novel heterozygous COL1A1 exon 14 variant (c.940G > A, p.Gly314Arg), presenting with a phenotype consistent with a COL1-related overlap syndrome. Conclusions: This case expands the phenotypic spectrum of COL1A1 mutations and supports the concept of COL1-related phenotypic overlap.

We describe the clinical, radiological, and oro-dental findings of four unrelated families with unusual skeletal phenotypes caused by mono- and bi- allelic COL1A1/2 variants. The study included five Arab patients with clinical manifestations resembling osteogenesis imperfecta in the presence of variable degrees of osteoporosis, bone deformities, gray sclera, Wormian bones in the skull, and oro-dental abnormalities. However, bone fractures, which are considered the cardinal feature in osteogenesis imperfecta patients, were not documented in any of the cases. In addition, they also lacked the characteristic features of Ehlers-Danlos syndrome. Exome sequence was used to identify the causative variants. A new homozygous missense variant in COL1A1: c.4340 T > G; p.(Val1447Gly) was identified in one family, while the remaining three families harbored two recurrent and one novel heterozygous variants in COL1A2: [c.1171 G>A; p.(Gly391Ser) and c.1253 G>C; p.(Gly418Ala)] and COL1A1: c.1678 G>A; p.(Gly560Ser), respectively. We present a new patient harboring a homozygous COL1A1 variant with a distinctive skeletal phenotype in comparison to the few previously reported patients in the literature. In addition, we describe three families with osteogenesis imperfecta like phenotype harboring monoallelic COL1A1/2 variants, expanding the spectrum of COL1-related overlap disorder.

Pyknodysostosis (PKND), also referred to as Toulouse-Lautrec Syndrome, is a rare autosomal recessive disorder marked by short limbs, short stature, and generalized bone sclerosis. The hallmark signs of this disorder include sclerosis of the terminal phalanges, persistent fontanelles, delayed suture closure, wormian bones, absence of frontal sinuses, obtuse mandibular gonial angle, and relative mandibular prognathism. This case report elucidates a 13-year-old boy presenting with systemic features such as short stature, frontal and parietal bossing, depressed nasal bridge, a beaked nose, hypoplastic midface, wrinkled skin on the fingertips, and nail abnormalities. The oro-dental manifestations include deep palate, prominent palatal rugae, constricted maxillary arch, proclined maxillary anterior teeth and Class III skeletal profile. Radiographic findings showed hypoplastic paranasal sinuses, atrophic mandible, taurodontism, impacted permanent teeth along with several retained deciduous molars. This case highlights the need for vigilance in identifying the dental and systemic signs of PKND, emphasizing the importance of early diagnosis and tailored treatment strategies to improve patient outcomes. Key words:Pyknodysostosis, Toulouse-Lautrec syndrome, Dental management.