Lehman syndrome: a new syndrome for pierre robin sequence

The Skeleton of Lateral Meningocele Syndrome

Notch (Notch1 through 4) are transmembrane receptors that determine cell differentiation and function, and are activated following interactions with ligands of the Jagged and Delta-like families. Notch has been established as a signaling pathway that plays a critical role in the differentiation and function of cells of the osteoblast and osteoclast lineages as well as in skeletal development and bone remodeling. Pathogenic variants of Notch receptors and their ligands are associated with a variety of genetic disorders presenting with significant craniofacial and skeletal manifestations. Lateral Meningocele Syndrome (LMS) is a rare genetic disorder characterized by neurological manifestations, meningoceles, skeletal developmental abnormalities and bone loss. LMS is associated with NOTCH3 gain-of-function pathogenic variants. Experimental mouse models of LMS revealed that the bone loss is secondary to increased osteoclastogenesis due to enhanced expression of receptor activator of nuclear factor kappa B ligand by cells of the osteoblast lineage. There are no effective therapies for LMS. Antisense oligonucleotides targeting Notch3 and antibodies that prevent the activation of NOTCH3 are being tested in preclinical models of the disease. In conclusion, LMS is a serious genetic disorder associated with NOTCH3 pathogenic variants. Novel experimental models have offered insight on mechanisms responsible and ways to correct the disease.

Infantile Presentation of Lehman Syndrome with Multiple Lateral Meningoceles, Dural Ectasias, and Herniation of Conus: A Rare Case Report

Lehman syndrome, or lateral meningocele syndrome, is a rare disorder of skeletal malformation, characterized by facial dysmorphism and multiple lateral meningoceles. We present a case of a 5-month-old girl who presented with macrocephaly, developmental delay, and failure to thrive. A whole spine magnetic resonance imaging was carried out, which showed multiple bilateral well-defined cystic masses within the neural foramina involving the entire spine, predominantly the thoracolumbar regions, with neural foraminal widening and dural ectasia suggestive of multiple lateral meningoceles.

Neurosurgical management in lateral meningocele syndrome: case report

Lateral meningocele syndrome (LMS) is a rare genetic connective tissue disorder. It is associated with morphological changes similar to those of other connective tissue disorders, with the unique distinction of multiple, often bilateral and large, lateral meningoceles herniating through the spinal foramina. In some cases, these lateral meningoceles can cause pain and discomfort due to their presence within retroperitoneal tissues or cause direct compression of the spinal nerve root exiting the foramen; in some cases compression may also involve motor weakness. The presence of lateral meningoceles imposes unique challenges related to CSF flow dynamics, especially with concurrent Chiari malformation, which also occurs with increased frequency in individuals with LMS. The authors present the case of a 6-month-old female with LMS with multiple lateral meningoceles throughout the thoracic and lumbar spine. The infant experienced a focal neurological abnormality due to enlargement of her lateral meningoceles following decompression of a symptomatic Chiari malformation and endoscopic third ventriculostomy. The finding was reversed through implantation of a ventriculoperitoneal shunt, which reduced the burden of CSF upon the lateral meningoceles. Such a case compels consideration that CSF flow dynamics in addition to altered connective tissue play a role in the presence of lateral meningoceles in patients within this and similar patient populations.

Lateral meningocele (Lehman) syndrome: A child with a novel NOTCH3 mutation

Lateral meningocele syndrome (LMS), or Lehman syndrome, is a rare disorder characterized by multiple lateral spinal meningoceles, distinctive facial features, joint hypermobility and hypotonia, along with skeletal, cardiac, and urogenital anomalies. Heterozygous NOTCH3 mutations affecting the terminal exon 33 were recently reported as causative in six families with LMS. We report a boy with LMS, the fourteenth reported case, with a de novo 80 base pair deletion in exon 33 of NOTCH3. Our patient's prenatal findings, complex cardiac anomalies, and severe feeding difficulties further expand our understanding of this rare condition.

Truncating mutations in the last exon of NOTCH3 cause lateral meningocele syndrome

Lateral meningocele syndrome (LMS, OMIM%130720), also known as Lehman syndrome, is a very rare skeletal disorder with facial anomalies, hypotonia and meningocele-related neurologic dysfunction. 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. Lateral meningocele syndrome has phenotypic overlap with Hajdu-Cheney syndrome. We performed exome resequencing in five unrelated individuals with LMS and identified heterozygous truncating NOTCH3 mutations. In an additional unrelated individual Sanger sequencing revealed a deleterious variant in the same exon 33. In total, five novel de novo NOTCH3 mutations were identified in six unrelated patients. One had a 26 bp deletion (c.6461_6486del, p.G2154fsTer78), two carried the same single base pair insertion (c.6692_93insC, p.P2231fsTer11), and three individuals had a nonsense point mutation at c.6247A > T (pK2083*), c.6663C > G (p.Y2221*) or c.6732C > A, (p.Y2244*). All mutations cluster into the last coding exon, resulting in premature termination of the protein and truncation of the negative regulatory proline-glutamate-serine-threonine rich PEST domain. Our results suggest that mutant mRNA products escape nonsense mediated decay. The truncated NOTCH3 may cause gain-of-function through decreased clearance of the active intracellular product, resembling NOTCH2 mutations in the clinically related Hajdu-Cheney syndrome and contrasting the NOTCH3 missense mutations causing CADASIL.

Late diagnosis of lateral meningocele syndrome in a 55-year-old woman with symptoms of joint instability and chronic musculoskeletal pain

Lateral meningocele syndrome (LMS) 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. LMS has been observed in eleven patients with two instances of vertical transmission, and seven sporadic cases with an age at diagnosis ranging from 25 months to 33 years. We report on a further observation of LMS in a 55-year-old woman presenting with a long history of joint instability, chronic musculoskeletal pain, and iatrogenic bladder and anorectal dysfunction due to irreversible nerve damage after surgical excision of a meningeal cyst. Her clinical characteristics are compared with those of previously reported patients, as well as two further cases originally diagnosed with Hajdu-Cheney and Ehlers-Danlos syndromes, but displaying typical features of LMS.