Prenatal diagnosis of isolated femoral bent bone skeletal dysplasia: Problems in differential diagnosis and genetic counseling

Abstract

Severe localized and symmetric bowing of the femora, in the absence of other significant skeletal or nonskeletal abnormalities, is a rare prenatal ultrasound finding. A 38-year-old woman was referred at 19 weeks gestation and ultrasound of the fetus showed severe shortening, and marked symmetric bowing of the femora. A provisional diagnosis of kyphomelic dysplasia (KD) was made. The patient elected termination of pregnancy and post mortem assessments were most consistent with kyphomelic dysplasia. KD is bent-bone skeletal dysplasia that, in contrast to campomelic dysplasia, involves principally the femora with relative sparing of the remainder of the skeleton. KD can be difficult to distinguish, particularly from symmetric cases of femoral hypoplasia unusual facies syndrome (FH-UFS), and few prenatal diagnoses have been reported. Because KD is thought to an be autosomal recessive disorder, the possibility that definitive diagnosis may not be possible prenatally, and even by postmortem assessment in cases choosing to abort, is an important counseling consideration.

Stuve–Wiedemann syndrome: a skeletal dysplasia characterized by bowed long bones

“…In the Revised International Nosology and Classification of Genetic Disorders of Bone—200612, SWS has been classified under the bent skeletal dysplasias along with campomelic dysplasia (CMPD), Cumming syndrome and kyphomelic dysplasia17. Alternative diagnostic considerations in the setting of bowed femora and mild‐to‐moderate micromelia would be Antley–Bixler syndrome, femoral hypoplasia‐unusual facies syndrome (FH‐UFS), osteogenesis imperfecta (OI) and diastrophic dysplasia18–21. They can be diagnosed easily at birth based on clinical and radiological findings.…”

Can MR Imaging Be Used to Characterize Fetal Musculoskeletal Development?

“…In another report, investigators found 40% of cases to be false-positive for the detection of isolated clubfoot, all of which were diagnosed in the third trimester of pregnancy (5). Yet a third report described the difficulty in distinguishing between isolated bowed femurs and true dysplasia, making parental counseling a challenge (6).…”

Campomelic Dysplasia: Echographic Suspicion in the First Trimester of Pregnancy and Final Diagnosis of Two Cases

“…The closest nosological presentations are Antley-Bixler syndrome, which can show a sex reversal, and kyphomelic dysplasia [6,18] . The Stüve-Wiedemann and Cumming syndrome which belong to the same group in The International Nosology and Classification of Constitutional Disorder of Bones also belong to the differential diagnosis ( table 2 ).…”

“…Short first metacarpals or short second phalanges are sometimes observed. Other signs are less common such as the absence of one pair of ribs, vertebral ossification defects, clavicular hypoplasia and absence of olfactory bulbs and tracts [1,[5][6][7] . Crania facial dysmorphism includes macrocephaly, low-set ears, hypertelorism, long philtrum, micrognathia, flat facies and cleft palate [8] .…”