Zimmermann-Laband syndrome (ZLS) is a rare group of potassium channelopathies presenting with characteristic facial findings, gingival hyperplasia, hypertrichosis, hypoplasia of phalanges and nails, neurodevelopmental disorders, and intellectual disability. KCNN3 related ZLS3 has been recently recognized. We detected a de novo heterozygous c.1606G>A variant in the KCNN3 gene using clinical exome sequencing. Our patient presented facial dysmorphism, ptosis and strabismus, pectus excavatum, hypertrichosis of the trunk and limbs, tapering fingers, hypoplastic nails, and gingival hyperplasia but no neurodevelopmental disorder or behavioral problems. To the best of our knowledge, our case is the ninth case of ZLS3 syndrome in the literature. We report a further case of ZLS3 without intellectual disability who, in addition, had a normal development as an infant. Previous cases of monozygotic twins were reported carrying the same variant in the KCNN3 gene. Twin sisters carrying the same variant in our study were reported to have developmental delay, but their intellectual level is normal in adulthood. We suggest KCNN3 related ZLS3 may not be associated with any neurodevelopmental disorder; that is an important issue for genetic counseling.

Craniofrontonasal Syndrome is a very rare dominant X-linked genetic disorder characterized by symptoms such as hypertelorism, craniosynostosis, eye alterations, bifid nose tip, and longitudinal ridging and splitting of nails. Heterozygous females are usually the patients severely affected. To date, clinical or genetic data have not been published for these patients in Colombia. Here we report a female proband with coronal craniosynostosis, hypertelorism, strabismus, rotational nystagmus, high-arched palate, dental crowding, scoliosis, severe pectus excavatum, unilateral breast hypoplasia, and brachydactyly; diagnosed with Craniofrontonasal Syndrome with the novel heterozygous variant c.374A>C (p.Glu125Ala) in the EFNB1 gene. So far, she has been treated with physical therapy and surgical correction of the bifid nose and an umbilical hernia. To the best of our knowledge, this is the first report of a patient with this rare genetic disorder in Colombia, expanding its mutational spectrum and highlighting the importance of genetic evaluation of patients with craniosynostosis and facial dysmorphism.