Clinical Dysmorphology Lecture

Question 1

Dysmorphology

Answer 1

The study of abnormal morphogenesis, abnormal physical development, congenital anomalies, and syndromes

Question 2

Congenital anomaly

Answer 2

Any aberrant structural abnormality present at birth. Not all are genetic.

Question 3

Syndrome

Answer 3

Primary developmental anomaly of two or more systems due to a common etiology

Question 4

Association

Answer 4

a non-random recurring pattern of malformations with no defined etiology

Question 5

Sequence

Answer 5

Pattern of malformations due to cascading effect from single minor alteration in early morphogenesis

Ex: Pierre Robin Sequence: small mandible-posterior-superior displacement of the tongue-palatal shelves unable to fuse in the midline- cleft of the soft palate. The single anomaly is micrognathia

Question 6

Malformation

Answer 6

abnormal formation in tissue

Question 7

Deformation

(Definition, Associated factors, Common deformations)

Answer 7

Definition: Unusual forces on normal tissue

Factors associated with deformations:

Fetal: large fetus, multiple fetuses, malformed fetuses, oligohydraminos, unusual placental anatomy

Maternal: primagravida, small uterine size, small mother, uterine malformation, uterine fibroids

Common Deformations:

Head and Neck: Cranial molding, craniosynostosis, deformational plagiocephally-tortiocollis, micrognathia, mandibular asymmetry, external ear deformities

Limbs: Clubfoot, crowded/overlapping toes, tibial torsion, joint dislocation

Nerve Compression: facial nerve palsy, erb’s palsy

Question 8

Disruption

(Definition, common disruptions)

Answer 8

Disruption: breakdown of normal tissue

Common Disruptions:

Vascular disruption or ischemia:

Oculoauriculovertebral spectrum (OAV, hemifacial microsomia, Goldenhar syndrome):disruption of blood supply to developing branchial arteries. One side of the face is underdeveloped.

Gastroschisis: disruption of right omphalomesenteric artery

Porencephalic cysts

Ileal atresia

Early amnion rupture: cranial anomalies, facial clefts, absent limbs or digits, anterior abdominal wall defects

Question 9

Causes of common congenital birth defects

Answer 9

Etiology of Abnormal Development:

Chromosomal, single gene, multifactorial, epigenetic, environmental

Question 10

Discuss the process of evaluating a patient who is dysmorphic or who has multiple congenital anomalies

Answer 10

1. Collect Data:

Family History: Use pedigree, other affected members, infertility, spontaneous miscarriages, parental appearance, consanguinity, ethnicity

Maternal history: Maternal and paternal age, weight gain, nutrition, illnesses, bleeding, infection, amniotic fluid volume, teratogenic exposures, premature labor, delivery, placental pathology. Paternal age also important factor new dominant disorders.

Fetal History: growth, activity, prenatal screening, fetal imagine, prenatal diagnostic testing (ex: Amniocentesis: Karyotyping), developmental milestones, health, academic, behavioral

Growth analysis: Focus on symmetry. Height, weight, head circumference-microcephaly and macrocephaly, pattern of growth- correct for prematurity until 2yrs old(CDC until 3, then Nelhaus). Slow and steady growth is okay.

Examination:

Traditional Exam: Observe dysmorphic features, Measure when appropriate, Quantitate findings, Photograph anything of interest

What is normal: how midface compares- pupils straight down to corners of mouth. Inner eyes straight down to edge of nose Eyes- straight across?

Objective measurements: Hand: Hand length, palm length, middle finger length

2. Establish a differential diagnosis: Use texts and databases to create a problem list.
3. Initial Laboratory and Imaging Studies: Karyotype, Microarray-CGH or FISH, x-ray, MRI, CT, ultrasound
4. Analysis of data collected, modify differential: Consider normal and family variation, use embryology benchmarks, use minor anomalies as clues, pathognomonic features, consistent features Pattern Recognition
5. Additional detailed testing:
6. Confirmation of diagnosis if possible
7. Provide counseling and intervention