KBG syndrome: clinical features and specific dental findings

This investigation sought to identify the common manifestations of KBG syndrome in the literature and to determine the major oral abnormalities in a 12-year-old Chinese boy.

PUBMED search, using the keyword phrase "KBG syndrome," produced 20 articles. Due to the disparities in the quality of evaluations in the reports, any physical feature that was not discussed was assumed to be absent.

Of the 54 cases, including the present case, 36 (67%) were males. Mental retardation or global developmental delay was reported in 42 (78%) cases, while 46 (85%) exhibited shortness of stature. Oral features occurred in 53 (98%) cases; macrodontia was present in 49 (96%) cases; the present case was the only one with hyperdontia and a talon cusp. Other features were craniofacial anomalies, followed by abnormalities of the nose, hand, mouth, eyes, eyebrows, philtrum, costovertebrae, ears, and, less frequently, low hairline and lower extremity abnormalities.

Cardinal features of KBG syndrome include facial dysmorphism, short stature, skeletal anomalies, and mild developmental delay; intraorally, macrodontia of the maxillary central incisors occurs in most cases. This is the first known report of KBG syndrome in a Chinese subject and the only case with hyperdontia and a talon cusp.