Sleep-disordered breathing in children with pycnodysostosis.

Upper airway obstruction is a common feature in pycnodysostosis and may cause obstructive sleep apnea (OSA). The aim of our study was to analyze sleep-disordered breathing and respiratory management in children with pycnodysostosis. A retrospective review of the clinical charts and sleep studies of 10 consecutive children (three girls and seven boys) with pycnodysostosis seen over a time period of 10 years was performed. Six patients had severe OSA and/or nocturnal hypoventilation and were started on continuous positive airway pressure (CPAP) as a first treatment at a median age of 3.4 ± 2.6 years, because of the lack of indication of any surgical treatment. Three patients could be weaned after several years from CPAP after spontaneous improvement (two patients) or multiple upper airway surgeries (one patient). Three patients had upper airway surgery prior to their first sleep study with two patients still needing CPAP during their follow-up. Only one patient never developed OSA. Patients with pycnodysostosis are at a high risk of severe OSA, underlying the importance of a systematic screening for sleep-disordered breathing. Multidisciplinary care is mandatory because of the multilevel airway obstruction. CPAP is very effective and well accepted for treating OSA.

Genetic study of eight Egyptian patients with pycnodysostosis: identification of novel CTSK mutations and founder effect.

This is the first Egyptian study with detailed clinical and orodental evaluation of eight patients with pycnodysostosis and identification of four mutations in CTSK gene with two novel ones and a founder effect. INTRODUCTION: Pycnodysostosis is a rare autosomal recessive skeletal dysplasia due to mutations in the CTSK gene encoding for cathepsin K, a lysosomal cysteine protease. METHODS: We report on the clinical, orodental, radiological, and molecular findings of eight patients, from seven unrelated Egyptian families with pycnodysostosis. RESULTS: All patients were offspring of consanguineous parents and presented with the typical clinical picture of the disorder including short stature, delayed closure of fontanels, hypoplastic premaxilla, obtuse mandibular angle, and drum stick terminal phalanges with dysplastic nails. Their radiological findings showed increased bone density, acro-osteolysis, and open cranial sutures. Mutational analysis of CTSK gene revealed four distinct homozygous missense mutations including two novel ones, c.164A>C (p. K55T) and c.433G>A (p.V145M). The c.164A>C (p. K55T) mutation was recurrent in three unrelated patients who also shared similar haplotype, suggesting a founder effect. CONCLUSION: Our findings expand the mutational spectrum of CTSK gene and emphasize the importance of full clinical examination of all body systems including thorough orodental evaluation in patients with pycnodysostosis.

[Pycnodysostosis: about a case]. / Pycnodysostose: à propos d'un cas.

Pycnodysostosis is a very rare genetic disease of the bone characterized by osteocondensation associated with dysmorphic syndrome and growth retardation. This study aims to highlight the phenotypic abnormalities, the radiological signs, the therapeutic and evolutionary features of pycnodysostosis in a 11-year old child. The child was referred by his dentist for clinical evaluation. He was born to first-degree consanguineous parents and had recurrent spontaneous fractures since the age of 3 years. Clinical examination showed dysmorphic syndrome characterized by frontal hump, persistent anterior fontanelle, micrognathia, finger deformities, dental malposition, curved nails, asymmetric chest, lumbar spine scoliosis with severe growth retardation (-4DS). Skeletal X-rays showed bony densification of the skull base, persistent anterior fontanelle, dental malposition, diaphysometaphyseal densification of the long bones mainly at the level of the lower limbs with malunions and tapered phalanges of the hands. Bone densitometry was normal. The diagnosis of pycnodysostosis was retained based on the clinical and radiological signs. Genetic counselling was proposed to the family as well as dental and orthopaedic treatment. Pycnodysostosis is a rare disorder; diagnosis is sometimes difficult and delayed posing diagnostic problem due to its resemblance with osteoporosis. Treatment is essentially based on fractures and dental caries prevention.

Pycnodysostosis and the making of an artist.

Henri de Toulouse-Lautrec, a 19th century artist celebrated for his depictions of the Moulin Rouge and Parisian nightlife, suffered from an unknown disorder. His symptoms were not only rare, but also difficult to determine. Both during his lifetime and following his death potential diagnoses have proved controversial, including the most popularly supported suggestion of pycnodysostosis. Addressing the ongoing debate of Toulouse-Lautrec's diagnosis, this article reconsiders the evidence. It summarises multiple perspectives and draws on more recent medical research, while acknowledging that the available sources are often unreliable. Ultimately, while there may be no definitive solution to the mystery of Toulouse-Lautrec's diagnosis, it is possible to draw one conclusion. Observing its impact on his life and work, it is clear that the condition formed the foundation of Toulouse-Lautrec's artistic career, shaping the way he perceived the world and defining the artworks that are now so widely admired.

[Pycnodysostosis: a rare disease with frequent fractures]. / Picnodisostosis: una rara enfermedad con fracturas frecuentes.

Pycnodysostosis is a rare disease caused by a dysfunction of the osteoclasts due to a mutation in the cathepsin K gene. We present a case of a young adult patient with the above mentioned syndrome, who suffered an atypical fracture of the tibia after a low energy fall. Some bone changes that could have predisposed the fracture were observed when examined in the Emergency Department. Not long afterwards he suffered the same type of fracture in another tibia. Due to the conditions typical of the pycnodysostosis, the above mentioned fracture required an unconventional approach for this mid-shaft tibial fracture (osteosynthesis plate), combined with a longer consolidation time. The case was finally resolved satisfactorily.