Chromosomal abnormalities are common causes of birth defects that can affect neurological functions and various parts of the human body. Accounting for nearly 20% of all infant deaths, birth defects are the leading cause of infant mortality, according to the Centers for Disease Control And Prevention.
Three of the most common newborn aneuplodies are trisomies 13, 18, and 21. About one in 5,000 babies is born with trisomy 18, one in 16,000 is born with trisomy 13 and one in 700 babies is born with trisomy 21, the most frequently occurring chromosomal abnormality. Although women of all ages may have a child with trisomy 13, 18, or 21, the risk increases with advanced maternal age.
March was named National Trisomy Awareness Month to increase awareness of trisomy conditions and to provide resources and support to the trisomy community, as families are often ladened with uncertainty, anxiety, and sometimes, loss.
According to the National Institute of Health, trisomy conditions typically result from a random abnormal cellular division that occurs very early in development and are not passed from one generation to the next.
Trisomy 21 or Down syndrome
Children with Down syndrome experiencelow growth, developmental delays, limited cognitive skills, and heart abnormalities. Other birth defects may consist of hearing, vision loss, and a number of health conditions, including feeding and swallowing delays. Physical characteristics may include depressed nasal bridge, low-set ears, mouth-breathing and brushfield spots and bilateral epicanthal folds. Visit the Down syndrome consortium to access research and support resources.
Trisomy 18 or Edwards syndrome
Children with Edwards syndrome experience severe birth defects and health problems involving nearly every organ system. Babies with trisomy 18 often have intrauterine growth retardation and a low birth weight. Additional trisomy 18 features include an abnormally small-shaped head, clenched fists, and wide-spaced eyes. Due to several life-threatening medical problems, many babies with trisomy 18 die before birth or within the first month. Only about 50% of babies born survive beyond the first six to nine days of life and only about 12% of babies born survive the first year of life. For support and patient resources, visit the NIH Resource.
Though there is no proven cause or genetic predisposition for trisomy 18, the NIH reports partial trisomy 18 can be inherited. An unaffected person may carry a rearrangement of genetic material between chromosome 18 and another chromosome, which is called a balanced translocation. Though they don't have any clinical signs of trisomy 18, individuals who carry this type of balanced translocation are at an increased risk of having children with Edwards syndrome.
Trisomy 13 or Patau syndrome
Children with Patau syndrome are typically born with heart defects, brain or spinal cord abnormalities and server intellectual disabilities. It is not uncommon for babies to have extra fingers, toes, or a cleft lip or palate. Due to several life-threatening medical problems, many infants with trisomy 13 die within the first days or weeks of life. According to the NIH, only 5-10% of children live beyond the first year. For additional support and patient resources, visit Support Organization for Trisomy 18, 13 and Related Disorders (SOFT).
Participate in Trisomy Awareness Month by registering for this month's webinar!