Ultrasonographic features in a case of heterozygous achondroplasia at 25 weeks' gestation

Abstract

Prenatal diagnosis of heterozygous achondroplasia at 25 weeks is described. First-level fetal ultrasonography demonstrated short long bones of the lower limbs. Second-level examination showed a large head; shortened femur, fibula, and tibia; a 'trident'-shaped hand; and an abnormal facial profile.

New aids for the non‐invasive prenatal diagnosis of achondroplasia: dysmorphic features, charts of fetal size and molecular confirmation using cell‐free fetal DNA in maternal plasma

“…Prenatal sonographic diagnosis often fails as limb length is preserved until around 22 weeks' gestation, after the time of the routine fetal anomaly scan6–10. Presentation of de novo cases often occurs in the third trimester when the fetus is scanned for some other reason and short limbs and other features, such as trident hand and frontal bossing6, may be evident. Even then, misdiagnosis is common11.…”

Errors in the Prenatal Diagnosis of Children With Achondroplasia

“…The prenatal diagnosis of bone growth disorders has become more common as ultrasound assessments have become more frequent. Nonetheless, the diagnosis of a specific skeletal dysplasia remains challenging (Muller and Cremin, 1985;Weldner et al, 1985;Kurtz et al, 1986;Romero and Sirtori, 1989;Cordone et al, 1993), despite efforts at diagnostic refinement such as the use of femur length-biparietal diameter ratios, vertebral body ratios, or facial profiles (Rouse et al, 1990;Kurtz et al, 1986;Cordone et al, 1993;Turner and Twining, 1993). Likewise, algorithmic approaches to the prenatal diagnosis of various skeletal dysplasias (Escobar et al, 1990;Spirt et al, 1990) most often do not lead to definitive diagnoses.…”

“…Even when expected, the prenatal diagnosis of heterozygous Ach by ultrasonographic examina-tion is difficult (Muller and Cremin, 1985;Weldner et al, 1985;Kurtz et al, 1986;Romero and Sirtori, 1989;Cordone et al, 1993). Cases of heterozygous Ach have a normal or close to normal femur length until 20-24 weeks [a feature allowing for differentiation from homozygous Ach (Patel and Filly, 1995)] and only thereafter does the growth rate of the femur decrease (Hall et al, 1979;Filly et al, 1981;Kurtz et al, 1990).…”

“…Cases of heterozygous Ach have a normal or close to normal femur length until 20-24 weeks [a feature allowing for differentiation from homozygous Ach (Patel and Filly, 1995)] and only thereafter does the growth rate of the femur decrease (Hall et al, 1979;Filly et al, 1981;Kurtz et al, 1990). Thus, one difficulty is the inability to diagnose Ach in the first half of the pregnancy (Fleischer et al, 1985;Weldner et al, 1985;Kurtz et al, 1986Kurtz et al, , 1990Spirt et al, 1990;Cordone et al, 1993;Sharony et al, 1993). Less attention has been paid to misdiagnosis when ultrasonographic evaluation does detect limb shortening.…”

Widening of the femoral proximal diaphysis-metaphysis angle in fetuses with achondroplasia

“…Many skeletal dysplasias present as short long bones noted at the routine anomaly scan. However, achondroplasia is not usually diagnosed at routine ultrasound screening in the second trimester, as the long bones are typically not shorter than expected until after 24 weeks' gestation. The diagnosis is usually made coincidentally when the mother has an ultrasound scan in the third trimester, resulting in many cases remaining undiagnosed prenatally.…”