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

Management of lateral meningocele syndrome in a child without neurological symptoms and literature review

PURPOSE

Lateral meningocele syndrome (LMS) is a rare genetic connective tissue disorder which is associated with meningocele-related neurologic dysfunction. Several patients with LMS have been reported. But, guidelines for screening and treatment of LMS have not been established.

METHOD AND RESULTS

We review the current knowledge of LMS in the article. Then, we describe a boy for whom a genomic analysis which allowed us to make a diagnosis of LMS and to begin monitoring of his condition for possible neurological complications.

CONCLUSION

It would be difficult to make a diagnosis of LMS on the basis of clinical manifestations alone. The natural history of dural ectasia in patients with LMS needs to be better defined to establish surgical indications. Based upon the current literature, ventriculoperitoneal shunting (V-Ps) has been recommended as the first-line surgical treatment option for patients with symptomatic thoracolumbar meningoceles.

Early diagnosis of lateral meningocele syndrome in an infant without neurological symptoms based on genomic analysis

Lateral meningocele syndrome is characterized by multiple lateral meningoceles with a distinctive craniofacial appearance, hyperextensibility of the skin, and hypermobility of the joints. The syndrome is caused by heterozygous truncating variants in the last exon, exon 33, of the NOTCH3 gene. Here, we present a 2-year-old girl for whom an early genomic analysis allowed us to recognize the presence of lateral meningoceles and to begin early monitoring of her condition for possible neurological complications. She had a characteristic facial appearance, hyperextensibility of the skin and mobility of the joints, and developmental delays. Given that lateral meningocele syndrome is a rare syndrome, the existence of lateral meningoceles is suspected only when the causative gene is detected by genetic testing. MRI scans are unlikely to be performed in infancy in the absence of neurological symptoms suggestive of meningoceles. No formal guidelines have been established for the neurosurgical indications for lateral meningocele syndrome. Given the features of hyperextensibility of the skin and hypermobility of the joints, lateral meningocele syndrome can be categorized as a connective tissue disease and may be progressive, as with the dural ectasia in Marfan syndrome and Loeys-Dietz syndrome. Watchful monitoring of dural ectasia may be warranted in patients with lateral meningocele syndrome.

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 of Lateral Meningocele Syndrome: A Clinical Update for the Pediatric Neurosurgeon

BACKGROUND

Lateral meningocele syndrome (LMS) is an exceedingly rare connective tissue disease with phenotypic anomalies similar to those seen in Marfan syndrome, Ehler-Danlos syndrome, and Loeys-Dietz syndrome. However, this syndrome is invariably associated with the presence of multiple lateral thoracolumbar spinal meningoceles: a distinct point of phenotypic divergence from other connective tissue disorders. The etiopathogenesis of this syndrome has recently been linked to truncating mutations within exon 33 of NOTCH3. Despite numerous reports, neurosurgical management of multiple spinal meningoceles remains poorly defined in the literature. We conducted a literature review to provide insight into the nosology, clinical significance, and neurosurgical management strategies of this distinct connective tissue disorder.

SUMMARY

Our literature search revealed 11 articles (16 cases) of LMS, which included 9 males and 7 females, belonging to 14 different families. Half of these cases underwent genetic screening: all of which were discovered to exhibit a truncating mutation within exon 33 of NOTCH3. All patients exhibited multiple lateral thoracolumbar spinal meningoceles with craniofacial dysmorphisms. Other clinical characteristics included pathologic changes in spine morphology, Chiari I malformation, syringomyelia, hydrocephalus, and tethered cord. Operative management of multiple spinal meningoceles in LMS is complicated by the presence of such coexisting structural neurologic pathologies, which may alter cerebrospinal fluid flow dynamics and, ultimately, impact operative intervention. Key Messages: LMS is an exceedingly rare connective tissue disorder with severe spinal dural involvement. Neurosurgical management of multiple spinal meningoceles is complex, which is further complicated by the presence of coexisting neuropathology, such as pathologic transformation of spine morphology and Chiari I malformation. Patients with a connective tissue disorder phenotype found to have multiple spinal meningoceles on imaging studies may benefit from evaluation by a medical geneticist and a pediatric neurosurgeon.

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.

Notch Signaling and the Skeleton

Notch 1 to 4 receptors are important determinants of cell fate and function, and Notch signaling plays an important role in skeletal development and bone remodeling. After direct interactions with ligands of the Jagged and Delta-like families, a series of cleavages release the Notch intracellular domain (NICD), which translocates to the nucleus where it induces transcription of Notch target genes. Classic gene targets of Notch are hairy and enhancer of split (Hes) and Hes-related with YRPW motif (Hey). In cells of the osteoblastic lineage, Notch activation inhibits cell differentiation and causes cancellous bone osteopenia because of impaired bone formation. In osteocytes, Notch1 has distinct effects that result in an inhibition of bone resorption secondary to an induction of osteoprotegerin and suppression of sclerostin with a consequent enhancement of Wnt signaling. Notch1 inhibits, whereas Notch2 enhances, osteoclastogenesis and bone resorption. Congenital disorders of loss- and gain-of-Notch function present with severe clinical manifestations, often affecting the skeleton. Enhanced Notch signaling is associated with osteosarcoma, and Notch can influence the invasive potential of carcinoma of the breast and prostate. Notch signaling can be controlled by the use of inhibitors of Notch activation, small peptides that interfere with the formation of a transcriptional complex, or antibodies to the extracellular domain of specific Notch receptors or to Notch ligands. In conclusion, Notch plays a critical role in skeletal development and homeostasis, and serious skeletal disorders can be attributed to alterations in Notch signaling.

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.

Lateral meningocele with asymmetric canal stenosis: A case study

Lateral meningocele is a very rare disorder of unknown aetiology typified by the presence of protrusions of the arachnoid and the dura matter extending laterally through inter- or intra-vertebral foramina. We report here the case of a 52-year old male with abnormality of spine when presented with low back pain. The patient did not appear to have any neurological disorder. A computerized tomography (CT) scan was acquired from T12 to mid sacrum with multiplanar reformations. The results showed the presence of a left sided paraspinal cystic lesion projecting from the left neural foramen and extending into the left psoas muscle suggesting a lateral meningocele. In addition, a broad based central and left paracentral disc protrusion was also observed resulting in asymmetric canal stenosis. The patient is on regular follow-up while undergoing palliative treatment.