Mondo Description 17q12 microdeletion syndrome is a rare chromosomal anomaly syndrome resulting from the partial deletion of the long arm of chromosome 17 characterized by renal cystic disease, maturity onset diabetes of the young type 5, and neurodevelopmental disorders, such as cognitive impairment, developmental delay (particularly of speech), autistic traits and autism spectrum disorder. Mullerian aplasia in females, macrocephaly, mild facial dysmorphism (high forehead, deep set eyes and chubby cheeks) and transcient hypercalcaemia have also been reported.