23 Chromosome Trisomy 18 Syndrome
638 Chromosome Trisomy 18 Syndrome 23 Chromosome Trisomy 18 Syndrome Edwards syndrome • Wide fontanels • Wormian bones Developmental and mental retardation, dolicho- • Thin calvaria cephaly, short palpebral fissures, micrognathia, over- • Hypoplasia of periorbital ridges lapping fingers, rocker-bottom feet • Hyper- or hypotelorism • Micrognathia (96%) Frequency: 1 in 5,000 births. Hands and Feet • Clenched hands, overlapping fingers Genetics • Ulnar deviation of the hand Trisomy 18; maternal age is a risk factor for aneu- • Hypoplastic thumbs, short 1st metacarpal ploidy; critical segment 18q11-q12. • Syndactyly, polydactyly, ectrodactyly • Short, hypoplastic, or absent finger phalanges Clinical Features • Equinovarus feet, rocker-bottom feet • Growth deficiency, failure to thrive • Toe syndactyly (2nd and 3rd toes most frequently • Hypoplastic skeletal muscle and subcutaneous fat involved) • Microcephaly, narrow bifrontal diameter, promi- • Hypoplastic, absent proximal hallucal phalanx nent occiput • Dysmorphic/absent toe phalanges • Short palpebral fissures, epicanthal folds, ptosis, Extremities microphthalmia, corneal opacities • Most pronounced changes involve the mesomelic • Short upper lip, small mouth, cleft lip/palate segments of the limbs • Micrognathia • Thin long bones • Low-set, dysplastic ‘fawn-like,’ posteriorly rotated • Tibial aplasia ears • Patellar aplasia • Shield-chest, short sternum, hypoplastic nipples • Genu valgum • Umbilical and inguinal hernia, diastasis recti • Radial hypoplasia • Cryptorchidism, hypoplastic labia
[Show full text]