Dysmorphology Basics

Question 1

What is the prevalence of major anomalies among liveborn infants?

Answer 1

2-3%

Question 2

When are most of the human structures in the body formed?

Answer 2

Between weeks 2-8 of development

Question 3

What is the prevalence of major anomalies among still born infants? Spontaneous abortions?

Answer 3

Still born: 15-20% Spontaneous abortions: higher

Question 4

What are some examples of CNS major malformations?

Answer 4

1. Neural tube defects (anencephaly, spina bifida, encephalocele) 2. Hydrocephaly

Question 5

What are some examples of major craniofacial, ophthalmologic, and ENT malformations?

Answer 5

1. Cleft lip with or without cleft palate 2. Cleft palate without cleft lip 3. anophthalmia or microophthalmia 4. anotia/microtia

Question 6

What are some examples of major cardiac malformations?

Answer 6

1. ASD or VSD 2. Tetralogy of Fallot 3. Trnsposition of great vessels 4. Truncus arteriosus 5. Hypoplastic left heart 6. coarctation of the aorta

Question 7

What are some examples of major gastrointestinal malformations?

Answer 7

1. esophageal atreasia/stenosis with or without fistula 2. rectal and large intestinal atreasia/stenosis

Question 8

What are some examples of major genitourinary malformations?

Answer 8

1. renal agenesis/hypoplasia 2. hypospadias or epispadias 3. bladder exstrophy

Question 9

What are some examples of abdominal compartment major malformations?

Answer 9

1. omphalocele 2. gastroschisis 3. diagphragmatic hernia

Question 10

What are some examples of major malformations of the extremities?

Answer 10

1. limb reduction defects

Question 11

What clues can minor malformations provide?

Answer 11

1. 3 or more minor anomalies indicate that a major anomaly may be present as well and should prompt investigation -2 minor malformations, 10% also have major malformation -3 minor malformations, 20% also have major malformation 2. 2 or more minor anomalies indicate that a syndrome may be present 3. timing of insult during prenatal development

Question 12

In general, when do most malformations arise? Disruptions and deformations?

Answer 12

Malformations: prior to 8 weeks (8 weeks marks end of organogenesis), although some structures (ex CNS) are still developing Disruptions, deformations: usually later than 8 weeks

Question 13

True or false: there is a higher incidence of malformations in premature or IUGR infants

Answer 13

True

Question 14

Define teratogen

Answer 14

Environmental influence that acts during gestation and alters morphology, function or growth -exert influence after fertilization but before delivery -Often cause malformations if exposure in first 8 weeks of fetus but can have differing effects if exposed later

Question 15

Name some findings in a newborn that should prompt a search for occult anomalies

Answer 15

1. Older parents 2. Family history of anomalies, spontaneous abortions, or stillbirths 3. History of teratogenic exposures 4. History of oligohydramnios or polyhydramnios 5. History of decreased fetal movement 6. Breech presentation 7. Prematurity or postmaturity 8. Overgrowth or undergrowth for gestational age 9. Discordance of measurements 10. Three or more minor anomalies 11. Failure of neonatal adaption 12. Persistent hypotonia or hypertonia

Question 16

What can decreased fetal movement represent

Answer 16

1. brain abnormality 2. other neuromuscular defects 3. limb malformations (ex arthrogryposis) 4. short limb skeletal dysplasia

Question 17

What should you always consider when evaluating a child with multiple malformations?

Answer 17

1. Are there environmental/non-genetic factors that could have caused this presentation? -drug -diabetic embryopathy -in utero vascular event -in utero infection -placental insufficiency

Question 18

What is one teratogen (not the only one) that can present with multiple malformations but no minor malformations?

Answer 18

=diabetic embryopathy