Familial syringomyelia: a report of four cases

Three sisters with Chiari I malformation with and without associated syringomyelia

Two daughters of non-consanguineous Ashkenazi Jewish parentage presented with occipital headaches in the second decade of life. Each had a symptomatic Chiari I malformation (CMI) and a large cervicothoracic syrinx. A third sister was diagnosed as having CMI without syrinx after MR screening of first-degree relatives. A fourth (the eldest) sister was asymptomatic and did not have CMI or syrinx. The girls' mother had platybasia on screening MR and a history of cough headaches. All four sisters also had demonstrable platybasic features on MR. The girls' father was asymptomatic and radiologically normal. This family represents the first reported case of three siblings in one family with confirmed CMI with or without syrinx. We discuss the possible genetic and mechanical mechanisms for the development of these abnormalities in this family.

Familial Chiari type I malformation with syringomyelia in two siblings: case report and review of the literature

OBJECTIVE

Familial cases of Chiari malformation with syringomyelia are rare. The majority of the reported series and case reports detail sporadic cases. The authors report two siblings who presented with Chiari type I malformation and syringomyelia (CMI+S).

CLINICAL PRESENTATION

We report two sisters who each presented with scoliosis on routine school physicals. Their clinical examination was unremarkable; however, imaging studies demonstrated a Chiari malformation with syringomyelia. Both underwent cervicomedullary decompression, and follow-up imaging studies revealed resolution of the syringomyelia.

CONCLUSION

A review of the literature reveals fewer than ten previous reports of familial CMI+S in the past 30 years. Although rare, the existence of familial cases of CMI+S suggests a genetic component to the pathogenesis of this condition in at least a proportion of patients. Neurosurgeons should be aware of the familial aggregation of CMI+S.

Syringomyelia in twin brothers discordant for Chiari I malformation: case report

Familial syringomyelia outside of trauma, tumor, or infection has been reported. Cases are presented that highlight the possible connection between familial syringomyelia and the Chiari 0 malformation. We report on 11-year-old twin brothers both with syringomyelia. Magnetic resonance imaging further revealed that one brother had Chiari I malformation and the other had Chiari 0 malformation. Both underwent posterior fossa decompression with radiologic improvement of their syringes. These case reports lend credence to earlier reports of improvement in syringomyelia following posterior fossa decompression in the absence of Chiari I malformation, the so-called Chiari 0 malformation. In addition, these case reports should influence the manner in which familial syringomyelia without tonsillar ectopia is defined and addressed, that is, posterior fossa decompression versus shunting of the syrinx, thereby addressing the potential cause of the syringomyelia and not only the enlarged cavity itself.

Chiari I malformation and neurofibromatosis type 1

Single case reports exist in the medical literature of patients with tonsillar ectopia, i.e., the Chiari I malformation and neurofibromatosis type 1. However, large series of patients with either of these entities have not been examined for the presence of both defects. We have retrospectively examined two large groups of pediatric patients: Group I, with the primary diagnosis of Chiari I malformation, who have undergone posterior fossa decompression for symptomatology; and Group II patients, who have been observed in our hospital's neurofibromatosis clinic for evaluation. Of 130 surgically addressed Chiari I malformations (Group I), we determined that 5.4% of these patients had the additional diagnosis of neurofibromatosis type 1. Of Group II patients (198) who underwent imaging of the brain, 8.6% were found to have a concomitant Chiari I malformation. These data suggest that Chiari I malformation and neurofibromatosis type 1 are not spurious findings but rather true associations. We hypothesize that the same early dysgenesis of mesoderm that is widely accepted as a culprit in the genesis of many Chiari I malformations is the same pathology affecting primitive development of tissues involved in many patients with neurofibromatosis type 1. Perhaps these data will aid in the determination of a genetic locus for the Chiari I malformation.

Idiopathic scoliosis as a presenting sign of familial neurologic abnormalities

STUDY DESIGN

Familial cases of "idiopathic" scoliosis associated with neurologic abnormalities are reported with a review of the literature.

OBJECTIVE

To investigate the prevalence of neurologic abnormalities such as syringomyelia, Chiari 1 malformation, and tonsillar ectopia in patients with genetically determined "idiopathic" scoliosis.

SUMMARY OF BACKGROUND DATA

Idiopathic scoliosis is widely considered to be a genetic disorder of unknown etiology. Magnetic resonance imaging (MRI) studies have shown that several cases of "idiopathic" scoliosis show neurologic abnormalities including syringomyelia and Chiari 1 malformation. Recently, several familial cases of either syringomyelia or Chiari malformation were reported, and it is suspected that genetic factors may influence the development of the craniovertebral malformation. It was hypothesized that some cases of "idiopathic" scoliosis include a craniovertebral malformation that is genetically determined.

METHODS

This study, using clinical examinations and MRI, investigated 71 patients with scoliosis and a family history of "idiopathic" scoliosis in third-degree relatives for the presence of neurologic abnormalities. If neurologic abnormalities were confirmed with MRI, the relatives affected with scoliosis were also examined.

RESULTS

Nine (13%) patients showed neurologic abnormalities on MRI. Magnetic resonance imaging showed syringomyelia with Chiari 1 malformation in four patients, Chiari 1 malformation in three patients, and tonsillar ectopia in two patients. Among the relatives of these patients, 4 of 15 individuals affected with scoliosis also showed neurologic abnormalities on MRI.

CONCLUSIONS

It is suggested that familial neurologic abnormalities may have a wide range of expression, and that some patients with "idiopathic" scoliosis present with genetically determined craniovertebral malformations such as syringomyelia, Chiari 1 malformation, and tonsillar ectopia.

Familial syringomyelia: the first Japanese case and review of the literature

We reported on syringomyelia in a mother and her son. The mother was 74-year-old, who developed gait difficulty at the age of 54. The son, 47-year-old, developed the same symptoms at the age of 35. In the both cases, MRI revealed syringomyelia with Chiari malformation. Twenty-one families with syringomyelia have been reported. The existence of these families indicates that genetic factors may play in role to the pathogenesis of this disorder.

Familial syringomyelia: case report and review of the literature

BACKGROUND

Syringomyelia is an uncommon disease of the spinal cord, occurring sporadically. However, rare familial cases with autosomal dominant or recessive inheritance patterns are reported and their incidence quoted as approximately 2%. Only one previous report originated from the United States.

METHODS

We present a brother and sister with syringomyelia and associated Chiari type I malformation; both patients responded to surgical treatment. We review the world literature and briefly discuss pathogenetic theories of syringomyelia as well as the relevance of the histocompatibility leukocyte antigen profile.

RESULTS

Both genetic and environmental factors appear to be involved in familial syringomyelia.

CONCLUSION

We recommend that close relatives of patients affected with familial syringomyelia undergo routine neurologic and radiologic surveys.

Syringomyelia: electrophysiologic aspects

The clinical and EMG findings in 44 patients with syringomyelia who were seen at the Mayo Clinic between 1976 and 1985 are presented. In 10 of the patients, somatosensory evoked potentials (SEPs) of the upper and lower extremities were obtained. All 44 patients had radiographic or surgical evidence of a cervical syrinx. The most common abnormality on nerve conduction studies was a reduced hypothenar compound muscle action potential amplitude (23 patients). Abnormal findings on needle electromyography were present in 33 patients and included sparse fibrillation potentials, reduced motor unit potential (MUP) recruitment, and chronic neurogenic MUP changes in muscles innervated by the C-5, T-1 roots, with the most pronounced changes in small hand muscles. Ulnar and median nerve SEPs were usually normal in the presence of a dissociated sensory loss and were usually abnormal when all sensory modalities were impaired. Abnormalities of tibial nerve SEPs were frequent and were related to impaired proprioceptive sensation in the lower extremities.

Familial syringomyelia

A woman with syringobulbia and syringomyelia and her sister with syringomyelia are described. The diagnosis was confirmed radiologically and surgically in the first sister and no other definite abnormalities of her craniocervical junction were found.