[6] Clinical features include gingival fibromatosis, hypoplasia of the distal phalanges, nail dysplasia, joint hypermobility, and sometimes hepatosplenomegaly.

[7] The nose and pinnae are usually large and poorly developed, which give individuals with the syndrome characteristic facial features.

Type 1 ZLS is caused by pathogenic variants (mutations) in a potassium channel gene – KCNH1.

[10][11] Type 2 ZLS is caused by pathogenic variants in the brain isoform of V-type proton ATPase subunit B, ATP6V1B2.

Affected individuals should see a pediatrician or adult physician at least annually to monitor growth, development and general health and well being.