A Chinese patient with KBG syndrome and a 9q31.2-33.1 microdeletion

KBG syndrome is characterized by postnatal short stature, macrodontia, facial and hand anomalies, delayed bone age and intellectual disability. KBG syndrome is an infrequently reported autosomal dominant condition caused by a mutation or haploinsufficiency of ANKRD11 at 16q24.3. We report on a patient, who showed many manifestations of KBG syndrome and was found to harbor a de novo ANKRD11 mutation, c.362T > A (p.Met121Lys). As the patient showed additional characteristics not occurring in KBG syndrome, a CGH array was performed which showed a de novo microdeletion of 9q31.2-q33.1. The majority of findings in our patient can be explained by the combined ANKRD11 mutation and 9q31.2-33.1 deletion. The case demonstrates well the need for comparing an abnormal genotype with a detailed phenotype analysis and the need for further studies in case the phenotype is unusual for the genotype.