Definition:

Lateral meningocele syndrome (LMS), also known as Lehman syndrome, is a rare hereditary connective tissue disorder characterized by pan-spinal meningoceles, specific facial dysmorphism, skeletal and soft tissue abnormalities, and hypotonia and/or muscle weakness. The characteristic lateral meningoceles represent the severe end of the dural ectasia spectrum and are typically most severe in the lower spine. Facial features of LMS include hypertelorism and telecanthus, high arched eyebrows, ptosis, midfacial hypoplasia, micrognathia, high and narrow palate, low-set ears, and a hypotonic appearance. Hyperextensibility, hernias and scoliosis reflect a connective tissue abnormality, and aortic dilation, a high-pitched nasal voice, wormian bones, and osteolysis may be present. NOTCH3 gain of function mediated via loss of the PEST degradation domain is associated with LMS.