kbg syndrome kbg syndrome kbg syndrome is a rare genetic disease that is the result of a mutation in the ankrd11 gene at location 16q24.3. only about a hundred known cases have been reported, although it is expected to be under-reported. kbg syndromesymptomsmacrodontia, brachycephaly, hypertelorism, synophrys, long philtrum, thin upper lip the syndrome was first described by herrmann in 1975 in three distinct families. herrmann proposed the name kbg syndrome after the initials of affected families' last names, which aren't known to the general public. characteristics features of individuals with kbg may include: distinctive facial features unusually large upper front teeth (macrodontia) a short, wide skull (brachycephaly) wide eyebrows that may grow together (synophrys) prominent nasal bridge thin upper lip widely spaced eyebrows (hypertelorism) a longer space between the bridge of the nose and upper lip (long philtrum) skeletal abnormalities cervical ribs delayed bone age curved pinky fingers flat feet short stature emotional or behavioral changes autism adhd anxiety developmental delays or mild to moderate intellectual disabilities