A skeletal dysplasia leading to a perinatal death in 17th–19th century Lisbon, Portugal

Abstract Congenital skeletal disorders are a heterogeneous group of anomalies that become evident during gestation. They are expressed in the shape and growth of the bones during development because of a defective genetic background. With the follow‐up of pregnant women and the advances in prenatal ultrasonographic examination and molecular genetic tests, nowadays, congenital skeletal disorders are identified at an early gestational age. If they are considered lethal, the termination of pregnancy is advised. This work unveils an exceptional instance of a rare pathological condition identified in a perinate (birth ± 2 weeks) from the 17th to 19th centuries, recovered during an excavation at the cloister of the São Domingos Convent in Lisbon, Portugal. The skeleton presents with exuberant modifications that include, among others, severe shortening (micromelia) and bowing of the long bones of the upper and lower limbs. The main skeletal findings indicated a presumptive general diagnosis of skeletal dysplasia, while the differential diagnosis includes hypophosphatasia, campomelic dysplasia, achondrogenesis, thanatophoric dysplasia, and severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN) as the most plausible causes for the observed skeletal changes. Even though an exact diagnosis is unattainable based only on the macroscopic analysis of the bones, the phenotypic features observed in this perinate are more consistent with thanatophoric dysplasia type 1.