Abstract
Pycnodysostosis is arare genetic disorder belonging to sclerosing skeletal dysplasias. Pycnodysostosis is caused by loss of function mutations in the cathepsin K(CTSK) gene which plays an important role in enzymatic digestion of the bone proteins, therefore osteoclasts cannot effectively break down the organic matrix of bone.
Deficiency of cathepsin Kresults in dwarfism, dysplasia of the skull and facial bones and phalanges, osteosclerosis, and fragility. It is inherited in an autosomal recessive trait.
The presented patient was referred to our department due to growth failure and orofacial abnormality. Anthropometric examination proved short stature with short limbs, narrow chest and shoulder, relative macrocephaly, delayed closure of the anterior fontanelle and mandibular hypoplasia.
He has short tips of fingers and onychodystrophy. Radiological examination ascertained diffuse osteosclerosis of the skeleton and acro-osteolysis of the distal phalanges.
On the basis of these findings the suspicion on Pycnodysostosis was pronounced. Molecular genetic testing proved this diagnosis.
The therapy of this disease is symptomatic and multidisciplinary, including assisted non-invasive ventilation due to sleep apnoea, orthopaedic treatment of fractures, dento-maxillar reconstructions, etc. The prognosis is quite promising, the disease is not progressive.
Knowledge of the key signs and early X-ray diagnosis of this inherited disorder will facilitate the prevention and treatment of common complications.