INFLUENCES ON PEDIATRIC HEALTH ( PART: I )
A. Heredity and genetics 1. Overview a. Heredity is the process by which living organisms product offspring like the themselves generics is the study of heredity. b. Congenital (present at birth) defects result from chromosomal abnormalities, monogenic (single-gene) mutations or other intrauterine factors. -) Alterations in the chromosome, part of a chromosome or gene can cause a genetic disorder. -) One or both biological parent may pass such alterations to a child or alterations may be new in the child. -) Many common defect (congenital heart disease, pyloric stenosis and central nervous system malformations) appear to be associated with multi factorial inheritance. -) Syndrome is the term used for a recognizable pattern of malformations due to a single specific cause, such as fetal alcohol syndrome and down syndrome. -) Association is the term used for nonrandom patterns of malformations for which an etiology has not been determined. VATER (vertebral defects, imperforate anus tracheoesophageal fistula and radial/renal defects ) is an example of an association. -) Certain problems, such as mental retardation, neural tube defects and cleft lip or cleft palate, can accur as part of a syndrome or an association and can here different etiologies, including single gene or chromosome abnormalities prenatal exposures (such as drugs or disease) or multi factorial causes. 2. Chromosome disorders a. Deviations in number of chromosome (i.e gain or loss of chromosome) are designed with the suffix somy. -) Monosomy refer to the loss of one chromosome from the pair. Monosomies are the rare and the fetus is usually nonviable. Turner’s syndrome (45 XO) is basically the only viable monosomy; however 99% of these fetuses are spontaneously aborted. -) Trisomy refers to an addition to a pair of chromosomes. Trisomies are relatively common. The most common include trisomy 13 (Patau’s syndrome), trisomy 18 (Edward’s syndrome) and trisomy 21 (Down syndrome). Down syndrome the most common chromosomal abnormality -can also from a translocation of chromosome 21-. b. Cell division errors can occur during either meiosis (gamete formation) or mitosis (post zygotic cell division), resulting in unequal distribution of genetic material. -) Alterations in the number of sex chromosomes typically do not cause serious effect. Klinefelter’s syndrome (47 XXY) is the most common sex chromosome abnormality. -) Numeric and structural autosome anomalies account for a collection of syndromes that are usually characterized by mental deficiencies. These include the trisomies listed above and classic deletions syndromes such as cri du chat syndrome (a short arm on chromosome 5). -) Fragile X syndrome results from a weakening in a long arm of an X chromosome. 3. Monogenic (single gene) disorders. a. Types of inheritance patterns include the following -) Autosomal dominant inheritance. Children of a heterozygote parent have a 50% chance of possessing gene. Children who do not inherit the defective gene will themselves have unaffected offspring. -) Autosomal recessive inheritance. Children of two heterozygous parent have a 25% chance of being affected. Unaffected children have 25% chance of carrying the gene and possibly passing it to their offspring. -) X-linked recessive inheritance. Males are usually affected; half the female children of affected fathers will be carriers and many pass the gene to their offspring. b. Traditional inheritance pattern account for only on third of genetic disorders. Other disorder can be attributed to gone variation, nontraditional inheritance and multi factorial disorders. 4. Nursing management a. Obtain a comprehensive history the includes family history and a history of problems that may suggest genetic disorders, such as congenital defects, growth abnormalities, hearing and vision problems, abnormal sexual development, metabolic disorders and develop mental disorders. b. Construct a pedigree chart. c. Encourage referral for genetic counseling, screening, and follow up. Labels: Pediatric |
