Our initial prenatal diagnosis was a cleidocranial dysplasia, which is the most frequent syndrome encountered with clavicle hypoplasia and wide skull sutures. This disease bears an orthopedic-only prognosis.
We also thought about pycnodysostosis, which was less likely.
Amniocentesis was performed and karyotype was normal, as well as the comparative genomic hybridization (CGH-array).

The baby has been delivered at 38 weeks of gestation naturally.
Failure to thrive was a pejorative element non-consistent with cleidocranial dysplasia. Clinical examination by the geneticist pediatrician concluded to a Yunis-Varón syndrome.

Yunis-Varón syndrome is a severe autosomal recessive disorder characterized by skeletal defects, including cleidocranial dysplasia and digital anomalies, and severe neurologic involvement with neuronal loss. Enlarged cytoplasmic vacuoles are found in neurons, muscle, and cartilage. The disorder is usually lethal in infancy.

Hypoplasia or aplasia of the clavicles may lead to discuss the following differential diagnoses:

• cleidocranial dysplasia: usually no neurological impairment.
• pycnodysostosis: diffuse bone sclerosis however with acro-osteolysis and clavicle osteolysis. Fractures are common. No neurological impairment.
• trisomy 13 or 18.
• acromandibular syndrome: usually no neurological impairment, ectodermal anomalies mimicking progeria condition featured in “fast-aging” syndromes.
• Yunis-Varón syndrome: severe failure to thrive, aplastic/hypoplastic thumbs and halluces might be a strong suggestive feature ⁴

Drs Cuillier, Balu and Alessandri also contributed to this case.