|Year : 2015 | Volume
| Issue : 2 | Page : 318-321
Pyknodysostosis: A rare case report
Deepti Bhardwaj1, Namita Raghav2, Vinay Mohan2, Pooja Singh1
1 Department of Oral Medicine and Radiology, Maharana Pratap College of Dentistry and Research Centre, Gwalior, Madhya Pradesh, India
2 Department of Oral Medicine and Radiology, KD Dental College and Hospital, Mathura, Uttar Pradesh, India
|Date of Submission||05-Oct-2014|
|Date of Acceptance||08-Oct-2015|
|Date of Web Publication||21-Nov-2015|
Jagdish Kripa, Besides Harinirmal Cinema Hall, Nai Sadak Lashkar, Gwalior - 474 001, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Pyknodysostosis is a rare autosomal recessive disorder characterized by the postnatal onset of short limbs, short stature, and generalized hyperostosis along with acro-osteolysis with sclerosis of the terminal phalanges, a feature that is considered essentially pathognomonic. Other features include persistence of fontanelles, delayed closure of sutures, wormian bones, absence of frontal sinuses, and obtuse mandibular gonial angle with relative mandibular prognathism. Here, we report a case of pyknodysostosis found to be having the classical features during intraoral examination and general physical examination.
Keywords: Acro-osteolysis, cleidocranial dysplasia, osteopetrosis, pyknodysostosis
|How to cite this article:|
Bhardwaj D, Raghav N, Mohan V, Singh P. Pyknodysostosis: A rare case report. J Indian Acad Oral Med Radiol 2015;27:318-21
| Introduction|| |
Pyknodysostosis is a rare clinical entity, first described in 1962 by Maroteaux and Lamy. The disease has also been named Toulouse-Lautrec syndrome, after the French artist Henri de Toulouse-Lautrec, who (it has been surmised) suffered from the disease. In 1996, the defective gene responsible for pyknodysostosis was located, offering accurate diagnosis, carrier testing, and a more thorough understanding of this disorder. It is an autosomal recessive osteochondrodysplasia, usually diagnosed at an early age with incidence estimated to be 1.7 per 1 million births. Pyknodysostosis is a lysosomal storage disease of the bone caused by a mutation in the gene that codes the enzyme cathepsin K (CTSK). 
Pyknodyostosis occurs in both sexes in varying age groups. The principle features of the syndrome such as short stature, open fontanels, frontal and parietal bone bossing, open sutures and fontanels, straightened mandible (obtuse angle of the mandible), dysplastic clavicles, and total or partial aplasia of terminal phalanges are the other classical features; bone also becomes sclerotic with high future susceptibility. Radiographically, there is hypoplasia of facial bones, non-pneumatization of paranasal sinuses, and partial or complete aplasia of distal phalanges. Crowding of the teeth with multiple impacted supernumerary teeth is the prominent intraoral feature of the disease. Other intraoral features include high-arched palate, enamel hypoplasia, and obliterated pulp chambers. 
| Case Report|| |
A 55-year-old male reported to the Department of Oral Medicine and Radiology with a chief complaint of pain and pus discharge in his all teeth since 2 months. Personal history revealed lack of brushing; patient swished his oral cavity with water in the morning and after every meal and used neem stick three to four times a week. On general physical examination, he demonstrated frontal bossing and hypoplastic midface, with relative mandible prognathism and nail abnormalities [Figure 1] [Figure 2] [Figure 3]. Intraoral examination revealed inflamed gingiva with pus discharge in all the teeth. On hard tissue examination, high-arched palate, multiple retained deciduous teeth, crowding, and enamel hypoplasia were found [Figure 4]. No history of pathological fracture and parental consanguinity was reported. On the basis of clinical findings, a provisional diagnosis of chronic generalized periodontitis was made and on the basis of general examination and intraoral features, pyknodyostosis was suspected and further investigations were carried out.
|Figure 4: Intraoral photograph showing crowding of teeth in upper and lower arches|
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Panoramic radiograph (OPG) showed multiple impacted permanent and supernumerary teeth in both maxillary and mandibular arches [Figure 5]. Lateral cephalogram showed relative mandibular prognathism and hypoplastic midface [Figure 6]. Posteroanterior (PA) view of the skull revealed absence of frontal sinus and hypoplastic paranasal sinuses [Figure 7]. Hand wrist radiograph showed acro-osteolysis of terminal phalanges [Figure 8]. Computed tomographic scan (CT) scan revealed multiple wormian bones along the sagittal and lambdoid sutures. All the sutures were closed, but not fused [Figure 9]. The differential diagnosis included osteopetrosis, idiopathic acro-osteolysis, and cleidocranial dysplasia. In the treatment plan, the patient was advised oral prophylaxis and medication, i.e. Cap. Doxycycline 100 mg BD for the first day followed by OD dose for the next 4 days, Tab. Serratiopeptidase 10 mg and Diclofenac potassium 50 mg combination BD for 5 days, and Chlorhexidine mouthwash 0.2% w/v BD for 5 days. Patient was also advised extraction of over-retained deciduous teeth followed by reconstruction surgery and prosthesis placement.
|Figure 6: Lateral cephalogram showing hypoplastic midface and obtuse gonial angle|
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|Figure 8: Hand wrist radiograph showing acro-osteolysis of terminal phalanges|
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| Discussion|| |
Pyknodysostosis is an autosomal recessive disorder of bone, causing osteoclast dysfunction resulting in osteosclerosis. The sclerosing activity of pyknodysostosis is due to a genetic defect on chromosome 1q21. This anomaly consists of mutations that produce mutational changes in a lysosomal cystine protease, CTSK, the expression of which is reduced in the osteoclasts. This protease is responsible for degrading Type 1 collagen that constitutes 95% of the organic bone matrix. The affected bones are abnormally dense and brittle as a result of insufficient resorption. ,,
The general features present in our case were short stature, nail abnormalities, and acro-osteolysis. Radiographs revealed over-retained deciduous teeth with multiple impacted permanent and supernumerary teeth, enamel hypoplasia, and crowding. Also, midface hypoplasia, obtuse mandibular angle with relative prognathism, and hypoplastic paranasal sinus were found in the lateral cephalogram and PA view. The CT scan showed wormian bones along the lamboidal sutures; also, it revealed that the sutures were closed but not fused. These findings correlate with those reported by Hunt et al., Landa et al., and Schmitz et al. ,,
The differential diagnosis of pyknodysostosis includes osteopetrosis, cleidocranial dysplasia, and idiopathic acro-osteolysis. In osteopetrosis, the bone marrow may be absent; therefore, hematopoietic alterations may appear frequently. Signs of compression of the cranial nerves exist, such as facial paralysis, deafness, or pain. Cleidocranial dysplasia may seem like pyknodysostosis in the presentation of clavicular agenesis or aplasia, as well as alterations of the skeletal bone membranes; however, bone density is not increased. In idiopathic acro-osteolysis, the appearance of the patients is typical, with hypotelorism, exophthalmoses, and an upturned nose. The angle of the mandible is acute and increased bone density is not present.  The diagnosis of pyknodysostosis is primarily based on the clinical features and radiographs; however, a CTSK gene mutation analysis is the confirmatory test. 
There is no specific treatment as of date for this disorder and treatment is supportive. Crowding can be dealt with planned extraction of retained deciduous teeth. Orthodontic treatment is not recommended because low remodeling capacity of the bone puts the patient at high risk of orthodontic failure. Extraction of tooth of these patients should be carried out with caution to avoid fracture of jaw bone and post-extraction osteomyelitis. The prognosis of this disease is good and no serious systemic alterations have been noted. Also, life expectancy for a pyknodyostosis patient is normal. ,
Declaration of Patient Consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]