Unusual Characteristics and Variable Expressivity in a Brazilian Family with Cherubism

Abstract

Cherubism is a rare genetic condition characterized by a bone nonneoplastic disease. We aimed to report a 6-year-old girl with cherubism presenting similar cases in the maternal family. However, her mother and grandmother seemed to be asymptomatic. The patient had an enlarged and asymmetric jaw with multiple enlarged cervical lymph nodes that increased in size with time. Sanger sequencing revealed a heterozygous mutation in exon 9 of SH3BP2 not only in the patient but also in her mother. Thus, we observed a variable expression and a probably reduced penetrance within the family, as well as unusual characteristics of the patient (in this case, the asymmetrical involvement of the jaw).

Keywords: asymmetry; cherubism; variable expressivity.

Fig. 1

Pedigree of the family showing the individuals presenting cherubism. The asterisk represents a maternal cousin who has a more severe expression of the disease. Below you can see the sequencing of the patient and her parents, showing that she and her mother had the SH3BP2 variant (NG_011609.1:g.43560C > T, NM_001122681.1:c.1253C > T, rs121909146). However, her mother was asymptomatic (# indicates the individuals who have undergone molecular evaluation).

Fig. 2

Appearance of the patient at the age of 6 years and 9 months. Note especially the increase of the mandibular region, which had a hardened consistency (A – C) . It is noteworthy that this increase in size was not symmetrical, being more pronounced on the left.

Fig. 3

Intraoral appearance showing the increased mandibular growth, mainly at left (A – C) . However, the patient did not present a cross-bite. In the panoramic radiograph of the face (D) . Multilocular bilateral expansive images can be seen along with absence of some primary teeth, as the two lower central incisors, and distal inclination of germs of others, as the lower first permanent molars, probably due to the osteolytic lesions (D) .

Fig. 4

Face computed tomography of the patient at the age of 11 years and 9 months revealing bilateral and marked expansion of the mandible, with malalignment of several teeth (A – D) .

Fig. 5

Three-dimensional reconstructed face computed tomography showing marked expansion and bilateral remodeling of the mandible, promoted by large cystic formations and multiloculated bone gaps (A – F) .