Genetic syndromes Flashcards
Smith-Lemli-Opitz syndrome S/S
low birth weight, microcephaly, characteristic facial features (bitemporal narrowing; hypertelorism; ptosis; epicanthal folds; large, low-set, posteriorly rotated ears; broad, flat nasal bridge; anteverted nares; cleft palate; micrognathia), skeletal abnormalities (polydactyly, syndactyly of second/third toes), underdeveloped male genitalia, severe photosensitivity, intellectual disability, and failure to thrive. Other features may include seizures, hypotonia, congenital heart defects, lung hypoplasia, and renal agenesis
Smith-Lemli-Opitz syndrome cause
inability to make cholesterol due to a mutation in the gene encoding 7-dehydrocholesterol reductase (DHCR7)
fragile X syndrome (FXS) s/s
macrocephaly; large, protruding ears; a prominent jaw; an elongated face; macroorchidism; and joint laxity. They often have autism spectrum disorder and intellectual disability (it is the second most common genetic cause for intellectual disability)
fragile x syndrome etiology
X-linked dominant condition caused by a mutation in the FMR1 gene due to a trinucleotide repeat expansion
Russell-Silver syndrome (RSS) s/s
profound intrauterine growth retardation, FTT- poor feeding, characteristic facial features (triangular-shaped face), and hemihypertrophy. In infants with RSS, the fronto-occipital circumference is preserved and results in relative macrocephaly compared to weight and height.
trisomy 18 (Edwards syndrome) s/s
intrauterine growth retardation, emaciated appearance with hypotrophy, hypotonia, microcephaly and dolichocephaly, microphthalmia, microretrognathia, limb anomalies (clenched hands with overriding digits, rocker-bottom feet), visceral malformations (cardiac, renal, gastrointestinal, genital), developmental delay, intellectual disability, feeding difficulties, and failure to thrive
trisomy 13 (Patau) s/s
heart defects, brain or spinal cord abnormalities, microphthalmia, extra fingers or toes, a cleft lip/ cleft palate, and hypotonia
