Bone and Soft-Tissue Disorders
[Henry Hubert Turner (18921970), chair of medicine at the University of Oklahoma, secretary and president of the Endocrine Society]
= nondisjunction of sex chromosomes as
- Complete monosomy (45,XO)
- Partial monosomy (structurally altered 2nd X chromosome)
- Mosaicism (XO + another sex karyotype)
Prevalence: 1÷3,0005,000 livebirths
Associated with: coarctation (2036% affected), aortic stenosis, horseshoe kidney (most common)
- sexual infantilism (spontaneous puberty in 515%):
- primary amenorrhea
- absent secondary sex characteristics
- short stature; absence of prepubertal growth spurt
- webbed neck; low irregular nuchal hair line
- shield-shaped chest + widely spaced nipples
- mental deficiency (occasionally); high palate; thyromegaly
- multiple pigmented nevi; keloid formation
- idiopathic hypertension; elevated urinary gonadotropins
- Cardiovascular
- dilatation of ascending aorta (40%)
- juxtaductal coarctation / pseudocoarctation of aortic arch (10%); aortic stenosis; bicuspid aortic valve; elongation of aortic arch; partial anomalous pulmonary venous return
- General
- normal skeletal maturation with growth arrest at skeletal age of 15 years
- delayed fusion of epiphyses >age 20 years
- osteoporosis during / after 2nd decade ← gonadal hormone deficiency
- coarctation of aorta (10%); aortic stenosis
- renal ectopia / horseshoe kidney
- lymphedema
- Skull
- basilar impression; basal angle >140°
- parietal thinning
- small bridged sella
- hypertelorism
- Axial skeleton
- hypoplasia of odontoid process + C1
- osteochondrosis of vertebral plates
- squared lumbar vertebrae; kyphoscoliosis
- deossification of vertebrae
- small iliac wings; late fusion of iliac crests
- android pelvic inlet with narrowed pubic arch + small sacrosciatic notches
- Chest
- thinning of lateral aspects of clavicles
- thinned + narrowed ribs with pseudonotching
- Hand + arm
- positive metacarpal sign = relative shortening of 3rd and 4th metacarpal
- positive carpal sign = narrowing of scaphoid-lunate-triquetrum angle <117°
- phalangeal preponderance = length of proximal + distal phalanx exceeds length of 4th metacarpal by >3 mm
- shortening of 2nd + 5th middle phalanx (also in Down syndrome)
- drumstick distal phalanges = slender shaft + large distal head
- insetting of epiphyses into bases of adjacent metaphyses (phalanges + metacarpals)
- Madelung deformity = shortening of ulna / absence of ulnar styloid process
- cubitus valgus = bilateral radial tilt of articular surface of trochlea
- deossification of carpal bones
- Knee
- tibia vara = enlarged medial femoral condyle + depression of medial tibial plateau (DDx: Blount disease)
- small exostosis-like projection from medial border of proximal tibial metaphysis
- Foot
- deossification of tarsal bones
- shortening of 1st, 4th, and 5th metatarsals
- pes cavus
US:
- prepubertal uterus
- nonvisualized / streaky ovaries (in complete monosomy); normal ovaries (in mosaic karyotype)
OB-US:
- large nuchal cystic hygroma
- lymphangiectasia with generalized hydrops
- symmetrical edema of dorsum of feet
- CHD (20%): coarctation of aorta (70%), left heart lesions
- horseshoe kidney
Bonnevie-Ullrich Syndrome
= infantile form of Turner syndrome
- Congenital webbed neck
- Widely separated nipples
- Lymphedema of hands + feet