There are different types of birth defects that cause physical or mental disability in the infant. Let us have a look at different birth defects in the following article.
Any structural, functional or metabolic abnormality that is recognized at birth is called birth defect. A birth defect can lead to many serious, life long disabilities and even death of many infants. It has been estimated that there are about three thousand different defects that we can inherit at birth. We shall have a look at these in the following paragraphs.
Most birth defects occur due to genetic abnormalities. When one abnormal gene or two recessive genes are passed on to the child from the parent it leads to these defects. The abnormal gene may occur due to addition or deletion in the number of chromosomes. Other causes include environmental factors. When a pregnant mother is exposed to harmful chemicals or diseases, it leads to certain disorders at birth. Exposure to lead, mercury, certain antibiotics, NSAID’s, antidepressants, etc. may also lead to these problems. Women who smoke and drink during pregnancy, may give birth to babies with physical or mental defects. In some cases, multi-factorial defects occur due to genetic as well as environmental factors. These defects may also occur without any apparent reason or cause.
There are two types of defects that occur at birth that may affect an infant: structural and development or functional birth defects. When one talks about structural defects, it means the infant will have problems with the body parts. Functional defects include those where the body parts or body system fail to function normally.
Chromosomal Birth Defects
When chromosomal abnormalities occur it leads to changes in the genetic coding of the infant. The infant may be born with too many or too few chromosomes. Sometimes, a few chromosomes may be broken or rearranged leading to defects in the infants. Down Syndrome is an example of the same.
About 6, 800 infants per year in the United States are born with oral facial clefts. These facial defects include cleft plate and cleft lip. This defect occurs due to multi-factorial factors that include genetics as well as environmental influence on the fetus. The infant’s mouth and/or lip do not fuse together completely during fetal development.
One of the birth defects that affects the brain is anencephaly. This occurs during the first week of pregnancy, a part of the neural tube that will form the brain does not close. These infants born lack a part of their scalp, skull and brain. This defect leads to loss of upper brain function and the infant unfortunately dies within the first few hours or days of its life. Other defects due to chromosomal abnormalities lead to Autism, Prader-Willi syndrome, Fragile X syndrome, speech or language difficulties, movement restrictions, etc.
One of the structural defects that affects the brain as well as spine is the neural tube abnormality called spina bifida. In this case, around 3 to 4 weeks of pregnancy, the neural tube that forms the spinal cord does not close completely. This causes different problems like mental impairment, muscle paralysis, loss of bladder and bowel control. There are three types of spina bifida: occulta (mildest form), meningocele (rarest form) and myelomeingocele (most common and most severe form).
The urethra opening in the male child is located on the underside of the penis instead of the tip is a reproductive defect. This birth defect occurs when the urethra is not completely developed in the fetus.
Congenital Heart Defects
One of the most common types that affects 1 in every 125 live births is heart defects. During the first trimester of pregnancy, most of the heart anomalies develop. These defects include ventricular septal defects (VSD), Tetralogy of Fallot, patent ductus aeteriosus (PDA), hypoplastic left heart syndrome, transposition of the great arteries, etc. These heart defects occur due to genetic abnormalities, alcohol abuse, medicine abuse, infections like rubella, etc. during pregnancy.
A birth defect called gastroschisis occurs when the intestines tend to protrude from the body next to the umbilical cord. The severity and size of the intestinal defects differs. This defect can be corrected with the help of surgery. However, the infant will face problems in the movement of the digestive food from the stomach and intestines as well as have problems absorbing nutrients.
Limb Birth Defects
When a part of one or both the arms or legs in the infant fails to develop completely, it causes limb deficiency. This condition affects about 1,500 infants/year in the United States. This defect occurs due to use of tobacco, chemicals, alcohol, certain medications and virus infections during pregnancy. When an infant is born with limb deficiency, this defect is called limb reduction defect.
When the infant has problems with the body’s metabolism, it affects a particular body process or chemical pathway. This leads to inability to get rid of toxic wastes and chemicals from the body. The child may suffer from blindness, destruction of brain cells, paralysis and even death. One such metabolic defect includes Tay-Sachs disease, phenylketonuria (PKU) and hypothyroidism.
When the sensory organs are affected it leads to a number of functional defects like loss of hearing (deafness), blindness, vision problems, etc. Other defects include chromatelopsia (type of color blindness), Darwinian ear (deformity of the helix of the ear), club foot (foot is twisted and down), cleft foot and hands, polydatyly (extra fingers and toes), aniridia (absence of iris at birth), brachydactylia (short fingers), etc.
Defects that lead to gradual loss of body functions and the health steadily declines with time it termed as degenerative birth defects. There are many degenerative disorders that affect an infants health and lead to gradual death. These degenerative disorders include lysosomal disorders, muscular dystrophy, Rett syndrome, X-linked adrenoleukodystrophy (X-ALD).
Not all the birth defects are visible or detected at birth. Doctors and parents may realize a birth defect with time, when they observe developmental and growth problems in the infants. Today, there are many tests that help determine these conditions when the fetus is in womb. However, many disorders do get missed and are seen after birth. For any further information, speak to your health care provider for more details.