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[Sibling case of osteosclerosis with cranial nerve symptoms]
Insights
Osteosclerosis is a rare genetic disorder characterized by bone hardening and distinctive facial features. Early diagnosis and management of complications like cranial nerve palsies are crucial for patients.
Area of Science:
- Genetics
- Rare Diseases
- Skeletal Dysplasias
Background:
- Osteosclerosis is an inherited condition with limited reported cases globally.
- Autosomal recessive inheritance and parental consanguinity are suggested.
- This abstract details two cases in sisters, highlighting the rarity in Japan.
Observation:
- Patients present with characteristic facial features including a broad nasal bridge, hypertelorism, and a prognathic mandible.
- Cutaneous syndactyly of hands and feet, particularly between the second and third digits, is common.
- Radiographic findings reveal systemic hyperostosis and osteosclerosis, with significant calvarial thickening.
Findings:
- Severe bone changes at the skull base lead to cranial nerve palsies due to foramen obliteration.
- Progressive hearing loss, facial nerve palsy, optic atrophy, and visual field defects are significant complications.
- Other symptoms include headache, convulsions, mental retardation, and potentially fatal brainstem compression.
Implications:
- Understanding the genetic basis and clinical manifestations is vital for early diagnosis and intervention.
- Management strategies should focus on preventing complications such as cranial nerve compression and increased intracranial pressure.
- Prophylactic surgical intervention, like foramen magnum opening, may be considered in adult cases to prevent sudden death.
Abstract:
We experienced two cases of "Osteosclerosis" who were 12 and 15 year old sisters. Previous reported cases of this disease are 50 cases and among them only one patient was reported in Japan. Osteosclerosis seems to be inherited as an autosomal recessive trait. Parental consanguinity is also observed. The peculiar facies are evident in infancy, characterized by broad, flat nasal bridge, ocular hypertelorism and prognathic, broadened mandible. Commonly, they have cutaneous syndactylies in bilateral hands and feet, especially between the second and third finger and toe. Roentgenographically, hyperostosis with osteosclerosis can be observed in systemic bones, particularly the calvarium is greatly thickened. Since such a bony change occurs most severely at the base of the skull, important clinical symptoms of this disease are cranial nerve palsies resulting from obliterations of unilateral or bilateral several cranial nerve foramina. In many cases deafness due to progressive encroachment upon the middle ear cavities and auditory nerve canals appears early in infancy. Transient palsy of the facial nerve occurs somewhat later, and bilateral facial paralyses are usually permanent in adulthood. In some cases optic atrophy and visual field defect due to compression of the optic nerves are late complications. Other ocular symptoms are strabismus, nystagmus and exophthalmos. Anosmia and trigeminal nerve palsy are less common. Lower cranial nerve symptoms can not be noted but the reason is unclear. Chronic headache, convulsion and mental retardation are occasionally present. They are considered as a result from increased intracranial pressure due to progressive diminution of the cranial capacity. By same mechanism, several patients have died suddenly from impaction of the medulla oblongata in the foramen magnum in early adulthood. Then, some reporter puts emphasis on prophylactic opening of the foramen magnum in all adult cases.