Genotypic and Phenotypic Characterization of Seven Individuals With Predicted Bone Morphogenetic Protein 2 (BMP2) Haploinsufficiency.

Bone morphogenetic protein 2 (BMP-2), encoded by the BMP2 gene located in chromosomal region 20p12, is a signalling protein involved in formation of bone and cartilage and other developmental processes such as cardiac and neural development. Haploinsufficiency of BMP2 has been associated with distinct facial features, short stature, skeletal malformations and cardiac abnormalities. The degree of developmental delay is still controversial. We summarise clinical and genetic findings from seven individuals with BMP2 haploinsufficiency. The study participants were identified by genetic testing and their phenotypic data was collected retrospectively from medical records. One individual had a novel frameshift variant in BMP2, and six individuals had 1.3-3.7 Mb microdeletions, including BMP2. In our cohort, delayed language development (4/5) and secretory otitis media (4/5) were common. Our results, together with previous studies, suggest that individuals with sequence variants or small microdeletions can have mild developmental delay or delay in one area (e.g., verbal development or gross motor development). We propose that global developmental delay is either a rare part or not part of the phenotype. Based on our observations, we propose that evaluation of language development and regular controls of the middle ear should be included in the surveillance of these individuals.