Blomstrand’s chondrodysplasia

Abstract Blomstrand’s chondrodysplasia (BOCD) (OMIM 215045) is an autosomal recessive disorder caused by inactivating mutations in the PTH/PTHrP receptor (PTH1R), leading to severe developmental abnormalities. This polymalformative syndrome, due to advanced skeletal maturation, is characterized by very short limbs and dwarfism; a narrow thorax; facial anomalies such as macroglossia, micrognathia, and depressed nasal bridge; as well as polyhydramnios, hydrops fetalis, hypoplastic lungs, protruding eyes showing cataracts, and internal malformation such as preductal aortic coarctation, possibly associated with functional hypoparathyroidism (hypocalcemia and hyperphosphatemia) with inappropriately high PTH levels, indicating a syndrome of PTH resistance. The disease can lead to fetal death or can present at birth. Diagnosis can be made as early as 12–13 gestational weeks by transvaginal ultrasound. The disorder is lethal and there is no treatment to date.