Prenatal sonographic evaluation of short-limbed dwarfism: an algorithmic approach.

Abstract

Prenatal sonographic evaluation of short-limbed dwarfism is initiated when a significantly shortened femur is found or by referral of a patient with a family history of skeletal dysplasia. If a short femur is demonstrated, all the long bones are measured and evaluated for bowing, fractures, and mineralization. The bone dysplasia is categorized according to whether it is mesomelic, rhizomelic, or micromelic and whether bowing or fractures are present. The fetal spine, head, thorax, hands, and feet are carefully evaluated to differentiate the type of bone dysplasia and to determine whether it is lethal. Serial examinations may be necessary. This approach will provide sufficient information to counsel the family, manage the pregnancy, and direct the postnatal evaluation.

Ultrasonic Diagnosis of Fetal Bone and Small Parts

“…Useful signs of mineralization are an unusually prominent falx, absent or decreased visualization of the spine, decreased bone echogenicity and nonuniform or weak acoustic shadowing. 20,[29][30][31] The fetal head, spine, thorax, abdomen, hands and feet are also observed at such time. A great deal of information relating to diagnosis and prognosis can be obtained from the relationships of these measured values, and calculations should be made for femur length foot length ratio (normal = 1, <1 suggests skeletal dysplasia), chest circumference less than the 5th percentile for gestational age (< 5th percentile for gestational age suggests lung hypoplasia), and femur length-abdominal circumference ratio (< 0.16 suggests lung hypoplasia).…”

“…20,21 ( Fig. 4) These classifications are based on postnatal radiological findings, and there are also cases in which prenatal ultrasound provides no clarification, but cases are first classified into three groups, and narrowing to candidate diseases incorporates additional findings, specifically, morphology and epiphyseal findings for tubal bones, findings for nontubal bones, such as …”

“…In these syndromes, Langer syndrome, Robinow syndrome and omodysplasia recessive type are an autosomal recessive, and others are hereditary autosomal dominant. 3,20,21 Mesomelic syndromes are attended by variegated systemic anomalies and require medical management for problems of limb function and appearance, but many are nonlethal, and the question of ability to make prenatal diagnosis does not influence neonatal outcomes. The intelligence is also generally normal, but Robinow syndrome can result in mental retardation.…”

“…48 The disease has an autosomal dominant inheritence, 20 and sonographic findings can include proportionately shortened tubal bones, small thorax with a decreased cardiothoracic ratio, occasional polydactyly (30%) and hydramnion.…”

“…51 This disease has an autosomal dominant inheritance and manifests anomalies in all three germ layers during the development process. 20,52 Sonographic findings can include normal growth, shortened tubal bones, small thorax with a decreased cardiothoracic ratio, polydactyly, congenital heart defects (50-60%, e.g. atrial septal defect, ventricular septal defect, single atrium).…”