Developmental and Genetic Disease 5

expressed in female offspring if dominant, always expressed in male offspring, never passed from father to son

Single copy of mutant allele will affect female phenotype

Never passes from father to son

All daughters of an affected male and a normal female are affected

All sons of an affected male and normal female are normal

males are more severely affected (may be lethal)

few described (Vitamin D-independent rickets)

softening and weakening of the bones

seen in males, females are carriers, most x-linked disorders are recessive

Most common type

Dystrophin required form muscles cells and structural support- w/o it, membrane becomes permeable, extracellular components enter the cell, increasing internal pressure until muscle cell explodes

Gower's sign, Pseduohypertrophy of calf muscles, and cardiomyopathy

DMD

use arms to push themselves erect by moving hands up their thighs

replacement of muscle fibers w/ fibroadipose tissue

Deficiency of Factor VIII

Potential for severe bleeding

Arthritis d/t hemorrhage into joint capsule

Treated w/ Factor VIII infusions

*Most common form of inherited mental retardation

Caused by expansion of CGG

Fragile site represents a specific locus on chromosome that breaks easiliy

Increased head circumference
Joint hyperextensibility
Heat valve abnormalities
Profound mental retardation

mutation in mitochondrial genome

affects: nervous, skeletal, heart because they need the most ATP

All vertebrae mitochondria are inherited from mother

Results from additive effects of several abnormal genes and envrionmental factors

Multiple genes interact w/ various envrionmental factors to produce disease in an individual patient

Based on # of mutant genes

Influenced by environment

More severe the defect, greater risk of transmission to offspring

sexual preference

amniocentesis and chorionic villus biopsy

indications: age 35+, familial hx, translocation of carrier

Predispostion: maternal illness, uterine/cervical incompetence, fetal disorder, placental abnormality

IUGR: impairment of maternal health and nutrition; interference w/ placental circulation/function; disturbance of development

Type 2 pneumocytes provide pulmonary surfactant (made of phospholipids)

Maturity tested by measuring surfactant in amniocentesis

lowers surface tension of alveoli a low lung volumes and thereby prevents collapse of alveoli during expiration

Leading cause of morbidity and mortality in premature infants

Deficiency of surfactant

conspicious extramedullary hematopoiesis

lack of glucuronyl transferase enzyme

inability of liver to conjugate bilirubin leading to neonatal jaundice

assessment taken 1-5 minutes after birth

higher score = healthier baby (out of 10)

A: appearance
P: pulse
G: grimace
A: activity
R: respiration

Development of maternal antibodies to fetal RBC antigen following exposure to antigen from fetus in pregnancy

Results from "D" antigen

1st pregnancy: during delivery mother is exposed to fetal blood, developing antibodies

Subsequent pregnancy: small amounts of fetal D antigen cross causing maternal response

Condition of fetus determined by amount of antibody transferred across placenta, ability of fetus to replace RBCs that were destroyed

clear heat & toxins

Elevated hemolysis leading to significant anemia

Severe edema and congestive HF

Severe jaundice w/ bile staining on the brain

Unconjugated bilirubin injures cellsof brain by interfering w/ mitochondrial function

Treated using exchange transfusions and phototherapy

Prevented by dosing Rh- mother w/ anti-D globulin 72 hrs before pregnancy

Poor obstetric manipulation

routine delivery

cephalopelvic disproportion; shoulder dystocia

Dystocia

Prematurity

Breech Presentation

Sudden death of child w/ unexpected medical hx, post mortem exam fails to demonstrate adequate cause of death

Leading cause of death during 1st year of life beyond neonatal period

SES
black race
Age < 20 w/ 1st pregnancy
Cigarette smoker
Illicit drug user

low birth weight
prematurity
illness (GI) 2 wks before death
Subsequent siblings of SIDS victims
Survivors of an apparent life threatening event

promote diuresis / treat stranguria