Monosomy 13q14 is a rare chromosomal anomaly syndrome, resulting from a partial deletion of the long arm of chromosome 13, characterized by developmental delay, variable degrees of intellectual disability, retinoblastoma and craniofacial dysmorphism (incl. micro/dolichocephaly, high and broad forehead, prominent eyebrows, thick, anteverted ear lobes, short nose with a broad nasal bridge and bulbous tip, prominent philtrum, large mouth with thin upper lip and thick, everted lower lip). Other features reported include high birth weight, macrocephaly, pinealoma, hepatomegaly, inguinal hernia and cryptorchidism.

A congenital brain malformation typically characterized by incomplete formation of the cerebellar vermis, dilation of the fourth ventricle, and enlargement of the posterior fossa. In layman's terms, Dandy Walker malformation is a cyst in the cerebellum (typically symmetrical) that is involved with the fourth ventricle. This may interfere with the ability to drain cerebrospinal fluid from the brain, resulting in hydrocephalus. Dandy Walker cysts are formed during early embryonic development, while the brain forms. The cyst in the cerebellum typically has several blood vessels running through it connecting to the brain, thereby prohibiting surgical removal.