<prompt> A baby is born with fused eyes, single nasal chamber and undeveloped callosum. What is diagnosis?HoloprosencephalySchizencephalyPlagiocephalyBrachycephaly  <response>: a. HoloprosencephalyRef: Nelson 20e p 901HoloprosencephalyAn abnormality of brain development in which the brain does not properly divide into the right and left hemispheres.3 main types from most to least severe: Alobar, semi-lobar lobarSeverity of facial defects corresponds to severity of brain defect.Other signs and symptoms often include intellectual disability, seizures, pituitary dysfunction, short statureAssociated with trisomy 13 MC, trisomy 18, CHARGE syndrome, Smith-Lemli-Opitz syndrome, Rubinstein-Taybi syndromeIn alobar holoprosencephaly, there is loss of midline structures of the brain and face as well as fusion of lateral 3rd ventricles of the brain. Facial findings may include a single eye cyclopia or very closely spaced eyes ethmocephaly or absent eyes anophthalmia, or very small eye microphthalmia with a tubular-shaped nose proboscis 