Congenital malformations of the central nervous system result from abnormalities that occur during a fetus's growth and development in the womb. Chromosomal abnormalities, maternal illness and drug abuse can cause congenital abnormalities which affect the normal growth of the baby's brain. Chromosomes carry the genetic material that is passed on to the baby from each parent.
According to the National Institute of Neurological Disorders and stroke (NINDS), this birth defect of the brain stems from the premature closure of the skull bones. Early closure of the skull suture restricts growth of the brain in that part and forces it to grow in an area of the brain where the sutures remain open. As the tiny brain attempts to grow during this unusual growth pattern, an increase in skull pressure can cause abnormal brain development to occur.
In cerebral palsy, genetic mutations and deletions cause the abnormal brain development in the fetus. The baby's brain does a poor job coordinating movement--cerebral palsy is not caused by problems with muscles themselves. According to the NINDS, research shows that few babies who are exposed to a low-oxygen environment during their birth will actually have cerebral palsy; most children who have cerebral palsy are born with it, and it is quite often detected months or even years later.
The disorder septo-optic dysplasia occurs because of abnormal formation of structures in the brain, specifically along the midline of the right and left halves of the brain, notes the Genetic Home Reference website. These parts of the brain may form abnormally or not at all. The optic or eye nerve and the pituitary gland at the base of the brain are underdeveloped in this condition.
Microcephaly refers to a brain that has not grown at a proper rate or has stopped growing somewhere along the way. According to the NINDS, genetic abnormalities are the most frequent cause with the cerebral cortex of the brain being affected. Down's syndrome, chromosomal abnormalities, alcohol and drug abuse, and maternal infections with German measles, chicken pox and cytomegalovirus are known microcephaly causes.
Abnormal brain growth in babies needs to have a long-term management plan that involves parents, caregivers and health care professionals.