4 weeks
CPT Code 
Test Code 
Test Methods 
Specimen Types Accepted 
Cultured Cells
Extracted DNA
Our SMC1A sequencing assay is validated to detect mosaic variants present at levels of 10% or higher. We recommend testing on buccal samples to enhance detection of mosaic variants.

Patients with Cornelia de Lange syndrome (CdLS) [OMIM #122470] have characteristic facial features, growth retardation, hirsutism, and upper limb reduction defects. More than 95% of patients with CdLS have limb involvement, but only 25% have severe limb anomalies. Characteristic facial features include synophrys, long eyelashes, depressed nasal bridge with an uptilted nasal tip and anteverted nares, thin upper lip with downturned corners of the mouth, and posteriorly rotated low-set ears. Most individuals have severe to profound mental retardation, but more mild cognitive delays have been reported. Mutations of the SMC1A [OMIM #300590] gene have been identified in patients with CdLS. Deardorff, et al. detected SMC1A mutations in approximately 5% of patients with CdLS (about 9% of those negative for NIPBL mutations). Patients with mutations in NIPBL tend to be more severely affected than those with mutations in SMC1A. No patients with mutations in SMC1A have been reported with limb reduction defects.

Contact the Cornelia de Lange Syndrome Foundation ( for more information and support.