This graph provides a snapshot view of structural defects at one place and time: A 2008 investigation in Atlanta, Georgia, determined that the distribution of birth defects was not even throughout the population, with the prevalence differing by both gender and race/ethnicity.
However, the higher prevalence among males decreased when defects that occur almost exclusively in males (such as hypospadias) were excluded.
They present at birth and result in a physical disability such as an oral cleft, spina bifida, congenital heart defects, and upper and lower limb reduction.
Historically, structural birth defects have been classified as either major or minor.
Babies with PKU cannot process phenylalanine, an amino acid (a building block of proteins) which then builds up in the blood and causes brain damage.
PKU is routinely detected with newborn screening tests, so affected babies can be placed on a special diet that prevents intellectual disability.The table below demonstrates that defining defects is complex and often overlapping.One defect may present with multiple forms of abnormalities.The timing of some exposures can influence or determine the effect.For example, an embryo exposed to the drug thalidomide between the 24th and 33rd day of gestation often suffers severe limb deformities, while those exposed at other times have either no or different health effects.Depending on where you look or with whom you speak, the term birth defect may include only structural birth defects.While not consistently used by the Centers for Disease Control and Prevention (CDC), this limited definition is used in the CDC’s birth defect prevalence estimates.Humans are diploid organisms, having two copies of each gene.A defect is dominant if a defect occurs when only one of the two gene copies within a person malfunctions.Oral clefts can occur alone (isolated) or alongside other birth defects.Isolated oral clefts are one of the most common birth defects in the US.