cherubism
, Cherubism
Clinical presentation and pathogenesis Cherubism is an autosomal-dominant genetic
defect that affects bone remodeling in the specific anatomically confined limits of the
embryologic mandible and sometimes of the mandible and maxilla. Cherubism does
not occur in any other bone and will not cross a bony suture to an adjacent bone.
Cherubism first begins to manifest itself by the age of 2.5 years and is fully
expressed by the age of 5 years. It affects males slightly
more than females because of a 100% genetic penetrance in males and only a
50% to 70% genetic penetrance in females. Its relatively rapid progression between
the ages of 2.5 and 5 years is often associated with regional lymphadenopathy and,
if the maxilla is involved, nasal obstruction with resultant mouth breathing . Nasal
obstruction is caused by enlargement of the middle concha. Because the genetic
defect is expressed on the embryologic maxilla or mandible only, the other
conchae—the inferior concha, which is an independent bone, and the superior
concha, which is part of the ethmoid bone—are not involved. The rapid evolution of
the disease often creates significant concern in the parents, particularly if the defect
is a spontaneous mutation and no direct family members or ancestors are known to
possess the condition. Spontaneous mutations, called sporadic occurrences, are
more common in cherubism than in most other inherited diseases and account for
up to 40% of cases.
Cherubism has three levels of expression.
Type I forms only in the bilateral rami of the mandible, sparing the condyle and
extending only to the third molar region. This form may be so subtle that it
escapes clinical detection until radiographs are taken years later. It is probable that
most of the reported cases of so-called bilateral giant cell lesions of the mandible
actually represent this type of cherubism, often called a forme fruste or incomplete
expression of the disease.
Type II forms mostly in the mandible and also spares the condyle, but it extends to
at least the mental foramen bilaterally and may include the posterior maxilla.
Type III is the form that prompted the name cherubism. This form involves the
mandible bilaterally to an advanced degree as compared to type II and also
includes most, if not all, of the maxilla . The involvement of the maxilla's contribution
to the orbital floor and orbital rim displaces the globes upward, causing a scleral
show. This feature, combined with the expansion of the maxilla, gives a child with
cherubism the chubby-faced appearance and the "upward-to- heaven" looking eyes
of a cherub. The maxillary involvement includes the alveolar bone and palate but
does not extend beyond the maxillary sutures. Therefore, the
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, Cherubism
Clinical presentation and pathogenesis Cherubism is an autosomal-dominant genetic
defect that affects bone remodeling in the specific anatomically confined limits of the
embryologic mandible and sometimes of the mandible and maxilla. Cherubism does
not occur in any other bone and will not cross a bony suture to an adjacent bone.
Cherubism first begins to manifest itself by the age of 2.5 years and is fully
expressed by the age of 5 years. It affects males slightly
more than females because of a 100% genetic penetrance in males and only a
50% to 70% genetic penetrance in females. Its relatively rapid progression between
the ages of 2.5 and 5 years is often associated with regional lymphadenopathy and,
if the maxilla is involved, nasal obstruction with resultant mouth breathing . Nasal
obstruction is caused by enlargement of the middle concha. Because the genetic
defect is expressed on the embryologic maxilla or mandible only, the other
conchae—the inferior concha, which is an independent bone, and the superior
concha, which is part of the ethmoid bone—are not involved. The rapid evolution of
the disease often creates significant concern in the parents, particularly if the defect
is a spontaneous mutation and no direct family members or ancestors are known to
possess the condition. Spontaneous mutations, called sporadic occurrences, are
more common in cherubism than in most other inherited diseases and account for
up to 40% of cases.
Cherubism has three levels of expression.
Type I forms only in the bilateral rami of the mandible, sparing the condyle and
extending only to the third molar region. This form may be so subtle that it
escapes clinical detection until radiographs are taken years later. It is probable that
most of the reported cases of so-called bilateral giant cell lesions of the mandible
actually represent this type of cherubism, often called a forme fruste or incomplete
expression of the disease.
Type II forms mostly in the mandible and also spares the condyle, but it extends to
at least the mental foramen bilaterally and may include the posterior maxilla.
Type III is the form that prompted the name cherubism. This form involves the
mandible bilaterally to an advanced degree as compared to type II and also
includes most, if not all, of the maxilla . The involvement of the maxilla's contribution
to the orbital floor and orbital rim displaces the globes upward, causing a scleral
show. This feature, combined with the expansion of the maxilla, gives a child with
cherubism the chubby-faced appearance and the "upward-to- heaven" looking eyes
of a cherub. The maxillary involvement includes the alveolar bone and palate but
does not extend beyond the maxillary sutures. Therefore, the
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