Larsen-Like Syndrome

Pierquin et al. (1991) reported the cases of 2 unrelated children with similar clinical features, particularly facial dysmorphism and multiple joint dislocations, suggesting the diagnosis of Larsen syndrome (150250). Both carried an inherited unbalanced translocation resulting in partial trisomy 1q and partial monosomy 6p. Skin collagen showed a decreased alpha-1/alpha-2 chain ratio in type I collagen (see 120150). Pierquin et al. (1991) suggested that both patients had a mutation in a gene involved in collagen production which is located either on chromosome 1q or, more likely, on 6p.

Chromosome 6 likewise came under suspicion in the family reported by James et al. (2003). The proband, a child with Larsen-like features and severe developmental delay, had an unbalanced translocation resulting in a distal 6p deletion and proximal trisomy 10q. The father and an unaffected older brother had a balanced form of the translocation, t(6;10)(p25;q25.2). James et al. (2003) suggested that the 2 translocation patients reported by Pierquin et al. (1991) and their patient supported the possibility of a locus responsible for a Larsen-like phenotype determined by genes in the distal 6p region. Their case had a more distal breakpoint, refining the potential critical region.