Down Syndrome Flashcards
What chromosomal abnormalities lead to DS?
Trisomy 21 (parents usually normal) Unbalanced translocation between 21 and another acrocentric (parent may have balanced, check their karyotype) Mosaic mix of Tri-21 (more mild)
Screenings for DS:
1st trimester: US to see nuchal folds, B-hCG + PAPP-A
2nd trimester: Quad screen (B-hCG, AFP, unconj. estriol, and inhibin)
1st + 2nd = 95% detection screening
NEW: fetal cells in maternal serum
Also… karyotype via amniocentesis performed at 16 weeks
High risk women get CVS at 11-12 weeks
What is the phenotype of an individual with DS?
Growth parameters are usually normal Midfacial hypoplasia brachecephaly upslanting palpebral fissures Epicanthal folds small ears large-appearing tongue hypotonia increased joint mobility short fingers, transverse palmar crease, 5th finger incurving (clinodactyly), increased space between toes 1 and 2 abnormal genitalia (esp males)
Cardiac issues
AV canal, must be surgically repaired
GI issues
Esophageal or duodenal atresia (blind pouch). Hirschsprung (missing nerve cells in distal colon, can’t propel stool). Feeding problems (hard to gain weight), constipation, GERD (all VERY common). Celiac is also common
Optho issues
blocked tear ducts, myopia, strabismus (lazy eye), nystagmus (jiggly), cataracts
ENT issues
chronic ear inf., deafness, chronic nasal congestion, enlarged tonsila, apnea (everything is too small)
Endocrine issues
Hypothyroid, Insulin-dep diabetes, alopecia, reduced fertility
Ortho issues
hip issues, joint subluxation, ATLANTOAXIAL SUBLUXATION (devastating; cervical paralysis)
Hematologic issues
myeloproliferative disorder, Inc risk of leukemia, Iron deficiency
Developmental issues
hypotonia affects motor development, intellectual disability, speech problems
Neuro issues
hypotonia, seizures (esp infantile spasms)
Psych issues
depression, early alzheimers, autism (1/10)
