Pycnodysostosis: A rare cause of short stature

Clinical and radiographic characteristics of pycnodysostosis: A systematic review

Purpose

Pycnodysostosis (PYCD), an autosomal recessive syndrome, is characterized by an imbalance in bone remodeling that produces various clinical and radiographic craniofacial manifestations. This review represents a systematic examination of these manifestations, as well as oral features associated with PYCD.

Materials and Methods

A systematic review was conducted across 8 databases from February to March 2023. The search strategy focused on studies reporting cases of PYCD that examined the clinical and radiographic craniofacial and oral characteristics associated with this syndrome.

Results

The review included 84 studies, encompassing a total of 179 cases of PYCD. More than half of the patients were female (55.3%), and the mean age was 14.7 years. Parental consanguinity was reported in 51.4% of the cases. The most common craniofacial clinical manifestation was a prominent nose, observed in 57.5% of cases. Radiographically, the most frequently reported craniofacial characteristics included the presence of an obtuse mandibular angle (84.3%) and frontal cranial bosses (82.1%). Clinical and radiographic examinations revealed oral alterations, with micrognathia present in 62.6% of patients and malocclusion in 59.2%. Among dental anomalies, tooth agenesis was the most commonly reported, affecting 15.6% of patients.

Conclusion

Understanding the clinical and radiographic craniofacial features of PYCD is crucial for dental professionals. This knowledge enables these clinicians to devise effective treatment plans and improve patient quality of life.

Pycnodysostosis- a rare disorder with distinctive craniofacial dysmorphia. A case report

Pycnodysostosis is a rare autosomal recessive condition caused by the mutation of CTSK gene. CTSK regulates the activity of Cathepsin K which is responsible for osteoclast-mediated bone resorption. This mutation causes the bones to become dense, sclerotic, brittle, and thus, prone to fracture. Affected individuals have normal cognitive development and life expectancy, however, the quality of life depends on the early diagnosis of the condition. The patient presents with striking clinical (short stature, brachydactyly) and radiological (frontal and parieto-occipital bossing, open sutures, and fontanelles, acro-osteolysis of terminal phalanges) features making the diagnosis clinico-radiographic. In atypical or mild cases with overlapping features, gene mapping is advocated. A plethora of dental anomalies and characteristic craniofacial dysmorphia puts the dentist in a position to diagnose such a case.

Spine radiograph in dysplasias: A pictorial essay

Spine radiograph is an essential component of a skeletal survey. It provides important diagnostic clues to various types of skeletal dysplasia. In some conditions, a spine radiograph alone may be diagnostic and characteristic; but mostly, it yields more value as a part of the complete skeletal survey. In this article we will discuss about a few common lethal and non-lethal skeletal dysplasias and their characteristic imaging findings; primarily focusing on the spine radiograph.

Multiple Fractures and Impaired Bone Fracture Healing in a Patient with Pycnodysostosis and Hypophosphatasia

Pycnodysostosis (PYCD) is a rare recessive inherited skeletal disease, characterized by short stature, brittle bones, and recurrent fractures, caused by variants in the Cathepsin K encoding gene that leads to impaired osteoclast-mediated bone resorption. Hypophosphatasia (HPP) is a dominant or recessive inherited condition representing a heterogeneous phenotype with dental symptoms, recurrent fractures, and musculoskeletal problems. The disease results from mutation(s) in the tissue non-specific alkaline phosphate encoding gene with reduced activity of alkaline phosphatase and secondarily defective mineralization of bone and teeth. Here, we present the first report of a patient with the coexistence of PYCD and HPP. This patient presented typical clinical findings of PYCD, including short stature, maxillary hypoplasia, and sleep apnoea. However, the burden of disease was caused by over 30 fractures, whereupon most showed delayed healing and non-union. Biochemical analysis revealed suppressed bone resorption and low bone formation capacity. We suggest that the coexistence of impaired bone resorption and mineralization may explain the severe bone phenotype with poor fracture healing.