| Question |
Answer |
| Indications for prenatal diagnosis |
Maternal age 35 or greater at delivery, Previous child with an abnormality, Parental balanced translocation or other chromosome rearrangement, Parents carry AR disorder, Mother carries X-linked disorder, Sex selection, Fetal structural abnormality by ultr |
| Increases with advancing maternal age |
Risk of non-disjunction (failure of chromosomes in a pair to separate during meiosis)...Aging of Ova, Spindle fibers, Cumulative effect of radiation, hormone effects, infection, Delayed fertilization (due to declining rate of coitus), Relaxed selection in |
| Advanced Paternal Age |
Insufficient evidence to provide risk; Predisposes fetus to |
| Down Syndrome |
80-90% due to maternal nondisjunction; 95% trisomy 21, rest are various translocations and mosaicism; Always mentally retarded; Congenital heart disease (CHD) in 40%; Life expectancy probably 50-60 years without CHD; With CHD 30% die by age 10 |
| Robertsonian translocation |
Involve two acrocentric chromosomes |
| risk of translocation with Carrier mother |
15% risk of translocation trisomy 21, |
| risk of translocation with Carrier father |
1-2% risk of translocation trisomy 21. |
| Neural tube defects |
geographic variation (1% N. Ireland, Scotland, Wales); female more common, happens at 4 weeks of development, not always paralyzed, incontinence, anesthesia, positional abnormalities |
| Spinal Bifida associated with deformity at base of brain |
Arnold Chiari malformation with hydrocephalus in 80% of cases |
| Causation of Neural Tube Defects |
Maternal nutrition, Seasonal, Valproic acid, Folate deficiency |
| Non-Invasive prenatal diagnosis |
serum screening for open body defects, chromosome abnormalities, and ultrasound |
| Maternal serum screening |
all markers depressed in trisomy 18 |
| Serum screening related findings w/ High maternal serum alpha-fetoprotein |
Spine defects, Abdominal wall defects, Placental abnormalities |
| Spinal Bifida |
severity depends on upper level of defect; bowel and bladder problems; postnatal surgery and shunting; 25% risk developmental problems; offer amniocentesis for aneuploidy |
| Encephalocele |
severe if includes brain; Can be mildly affected if only fluid; Counsel and refer; Offer termination |
| Abdominal wall defects |
Omphalocele (associated with other defects), Gastroschisis, Limb-body wall defect/amniotic bands |
| Gastroschisis |
Counsel about other malformations, Often bowel/vascular insults, Counsel about surgery, Watch for growth restriction, Monitor closely in 3rd trimester due to risk of demise |
| Trisomy 18 positive findings |
Choroid plexus cysts, Clenched hand with overlapping fingers, Clubbed foot, Omphalocele, Heart defects, Single umbilical artery (2-vessel cord), Intrauterine growth restriction, Cleft lip/palate, Increased nuchal lucency, Hydramnios due to tracheoesophag |
| Trisomy 18/13 counseling |
2/3-3/4 die in utero, never learn to walk/talk, 90% die by age 1 |
| cleft lip or palate |
offer amniocentesis including 22q deletion testing. can be associated with aneuploidy but good outlook with surgeries |
| Down Syndrome counseling: |
all mentally retarded, 40% congential heart defects, life span can be normal, offer amniocentesis and termination |
| Smith-Lemli-Opitz (SLOS) positive |
Microcephaly, Abnormal genitals, Limb abnormalities, Syndactyly/polydactyly, Renal anomalies, Heart defects |
| Head abnormalities |
Holoprosencephaly, Dandy Walker cyst, Vermian abnormalities |
| Clubbed foot |
Can be isolated, chromosomal, syndromic, neuromuscular or other etiologies |
| Invasive prenatal diagnosis |
Amniocentesis (15-20 weeks), Chorionic villus sampling (10-13 weeks), Fetal blood sampling (>16 weeks), Skin and Muscle biopsy |
Buen Viaje lv.2 ch 8
