Lethal Type Larsen-Like Syndrome

In 1982, Chen et al. described the lethal type Larsen-like syndrome as a connective tissue disorder characterized by multiple congenital joint dislocations (especially knee), facial abnormalities, skeletal deformities, tracheomalacia, and pulmonary hypoplasia (Chen et al. 1982). This syndrome is also associated with cerebral atrophy and brain dysplasia (Yamaguchi et al. 1996). Lethal type Larsen-like syndrome particularly involves the respiratory system and is highly fatal (Mostello et al. 1991). Pulmonary failure due to tracheomalacia or lung hypoplasia causes most patients to pass away shortly after birth (Chen et al. 1982). Symptoms typically appear in the fetal period or infancy (Mostello et al. 1991). There is a paucity of data regarding prevalence and incidence. Less than 1 in 1,000,000 people are estimated to be affected (Orphanet 2023).