A 26-year-old primigravida reported for the routine mid-trimester scan at a period of gestation of 18 weeks 5 days. The pregnancy was the product of a non-consanguineous marriage. Earlier, she had undergone a pregnancy confirmation scan at 6 weeks period of gestation. However, she did not have a routine first trimester scan for the assessment of markers of fetal aneuploidy. Her pregnancy was uneventful until then with no history of hypertension or raised blood sugar levels. Her family history was unremarkable. The second trimester clinical examination before the ultrasound did not reveal any abnormality.
The patient reported to the department of radiodiagnosis at our tertiary care center in Southern India for this scan as per hospital protocol. The ultrasound examination revealed multiple fetal abnormalities. It was a singleton pregnancy showing extreme micromelia with femur length (Hadlock) and humeral length (Jeanty) both corresponding to 13 weeks 4 days (Fig. 1). The ratio of femoral length and abdominal circumference (FL/AC ratio) was 0.08 (normal range 0.20–0.25), which indicated a lethal skeletal dysplasia . The most remarkable finding was almost complete non-visualization of vertebral body ossification centers (Fig. 2) with only two echogenic posterior elements seen in the transverse image of the fetal spine. Also, there was a gross increase in nuchal fold thickness which measured ~ 11.6mm (Fig. 3). There was relative macrocrania with normal-appearing ossification on ultrasound. There were no obvious brain abnormalities. The skull and ribs showed normal ossification. There was no evidence of neural tube defect, rib fractures, rib length discrepancy, or hydrops. The volume of liquor was normal.
Based on these findings, suspicion of type II collagen disorder was raised, and the patient was counseled about the poor prognosis. The patient opted for termination of pregnancy as Indian law allows termination of pregnancy up to 20 weeks for fetal abnormalities. The abortus (Fig. 4) showed marked micromelia, relatively large head, narrow thorax, and distended abdomen. Bilateral clubfeet were noted. No cleft lip or polydactyly was seen.
The postnatal radiographs of the abortus revealed severely short fetal long bones, complete non-ossification of vertebral bodies (including sacrum), relative macrocrania, narrow thorax, shortening of the trunk, cupped appearance of ribs without any fractures, and concavity of inferior and medial borders of ilium which has also been described as “paraglider appearance”  (Fig. 5). The ossification centers of ischium and pubis were also not visualized. The metaphyses of long bones appeared flared with lateral spurs seen at proximal metaphyses of bilateral humeri and femora. The skull appeared normal in size and mineralization.
The characteristic ultrasound and radiographic findings led to the diagnosis of achondrogenesis type II. No karyotyping or molecular analysis was done as the parents were unwilling for the same. The patient was counseled about the risk of recurrence of this condition in future pregnancy .
Ethics approval and consent to participate
The present study was approved by the ethical board of the hospital in which the study was performed. The parents of the fetus reported in this article had signed a written informed consent form. This case report was the reporting of a case in a medical educational center, in which all patients are informed that they may be subjects of scientific experiments and are informed of the ethical codes of conduct. This study complied with the latest version of the Helsinki Declaration.