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

Clinical and genetic heterogeneity in Dubowitz syndrome: Implications for diagnosis, management and further research

Dubowitz syndrome was described in 1965 as a recognizable syndrome characterized by microcephaly, short stature, eczema, mild developmental delays, and an increased risk of malignancy. Since its original description, there have been over 200 reported cases though no single gene has been identified to explain a significant proportion of affected individuals. Since the last definitive review of Dubowitz syndrome in 1996, there have been 63 individuals with a clinical, or suspected, diagnosis of Dubowitz syndrome reported in 51 publications. These individuals show a markedly wide spectrum with respect to growth, facial gestalt, psychomotor development, and risk of malignancy; genetic causes were identified in 33% (21/63). Seven individuals had deleterious copy number variants, in particular deletions at 14q32 and 17q24 were reported and showed overlap with the Dubowitz phenotype. Several cases were shown to have single gene disorders that included de novo or biallelic pathogenic variants in several genes including NSUN2 and LIG4 frequently identified by next-generation sequencing methods. It appears that the inability to identify a single gene responsible for Dubowitz syndrome reflects its extreme clinical and genetic heterogeneity. However, detailed phenotyping combined with careful grouping of subsets of unsolved cases and in conjunction with data-sharing will identify novel disease genes responsible for additional cases. In the interim, for those clinically diagnosed with a Dubowitz phenotype, we recommend assessment by a Medical Geneticist, a microarray and, if available, clinical or research based genome-wide sequencing. Management suggestions, including decisions regarding malignancy screening in select patients will be discussed.

Familial Chiari Type 1: A Molecular Karyotyping Study in a Turkish Family and Review of the Literature

BACKGROUND

The etiology of Chiari I malformation (CMI) has not been fully elucidated. Therefore, we performed a genetic study of a Turkish family in which 3 sisters had a diagnosis of CMI with or without syringomyelia.

METHODS

In a family with 7 children, 4 daughters complained of occipital headaches. In 2 of these daughters, CMI had been diagnosed during their 30s, and CMI plus syrinx had been diagnosed in the other daughter in her 40s. Cranial magnetic resonance imaging of the fourth daughter who had developed headaches during her 30s showed normal findings. Because the other siblings in the family were asymptomatic, radiological examinations were not performed. The family had a history of distant consanguineous marriage between parents. Additionally, the father had died, and the mother was asymptomatic, with radiologically normal findings. Array comparative genome hybridization studies were performed for 12 persons from 3 generations of this family.

RESULTS

None of the 12 cases examined harbored copy number variations.

CONCLUSIONS

This family with 3 sisters having CMI suggested a possible autosomal recessive single-gene etiology. Cases of familial CMI are unusual but important to study because they could reveal the specific genes involved in posterior fossa/foramen magnum structure and function and provide insights into the cause of sporadic cases.

[Treatment of syringomyelia associated with adhesive arachnoiditis]

The prevalence of syringomyelia (SM) caused by adhesive arachnoiditis (AA) is 2 to 4 cases per 100000 population. Surgical treatment of this pathology usually includes implantation of shunts into the cyst cavity or opening and drainage of the cavity. In this case, SM continues to progress in 72-100% of patients. Unsatisfactory outcomes of this surgical approach necessitate searching for other treatment options.

PURPOSE

To define the optimal amount of surgery for SM associated with AA and the criteria for assessment of surgery outcomes.

MATERIAL AND METHODS

The authors treated 47 SM patients in the period from 2010 to 2015. Of these, 34 (72.3%) patients underwent surgery; a total of 40 operations were performed. The patients' age ranged from 18 to 64 years (mean, 43.5 years). Tethering of the spinal cord was eliminated in 25 patients; 9 patients underwent cyst shunting.

RESULTS

Among operated patients, 5 patients had grade 1 arachnopathy, 13 patients had grade 2 arachnopathy, 12 patients had grade 3 arachnopathy, and 4 patients had grade 4 arachnopathy. The minimal postoperative follow-up period was 11 months. After shunting, the condition improved in 8 of 9 patients; in 7 patients, the condition returned to the baseline level within the first postoperative year; in 6 (66.7%) of these patients, the disease continued to progress. After surgical release of spinal cord tethering, satisfactory long-term results were achieved in 13 (86.6%) patients with grade 1-2 arachnopathy. In 3 (50%) patients with grade 3 arachnopathy, the condition was stabilized. Among patients with grade 4 arachnopathy, progression of the disease was stopped in 1 patient; the condition worsened in 2 (50%) patients. Among all the operated patients, complications developed in 7 patients. There were no lethal outcomes.

CONCLUSIONS

In grade 1-2 arachnopathy, progression of SM after release of spinal cord tethering occurs only in 13.4% of patients. Therefore, release of spinal cord tethering is recommended for these patients. In grade 3-4 arachnopathy, the rate of relapse after this surgery is more than 80%. Therefore, given the simplicity and a lower risk of complications of cyst shunting, this procedure is advisable for these patients.

Familial adhesive arachnoiditis associated with syringomyelia

Adhesive arachnoiditis is a rare condition, often complicated by syringomyelia. This pathologic entity is usually associated with prior spinal surgery, spinal inflammation or infection, and hemorrhage. The usual symptoms of arachnoiditis are pain, paresthesia, and weakness of the low extremities due to the nerve entrapment. A few cases have had no obvious etiology. Previous studies have reported one family with multiple cases of adhesive arachnoiditis. We report a second family of Belgian origin with multiple cases of arachnoiditis and secondary syringomyelia in the affected individuals.

Triple A (Allgrove) syndrome: an unusual association with syringomyelia

Triple A (Allgrove) syndrome was first described by Allgrove in 1978 in two pairs of siblings. Since then, about 100 cases have been reported, all of them displaying an autosomal recessive pattern of inheritance. Clinical picture is characterized by achalasia, alacrimia and ACTH-resistant adrenal failure. A progressive neurological syndrome including central, peripheral and autonomic nervous system impairment, and mild mental retardation is often associated. The triple A syndrome gene, designated AAAS, is localized on chromosome 12q13. It consists of 16 exons, encoding for a 546 aminoacid protein called ALADIN (Alacrimia-Achalasia-aDrenal Insufficiency Neurologic disorder).

We report on a 13 year-old boy presenting with Addison’s disease, dysphagia, muscle weakness, excessive fatigue and recent onset gait ataxia. The analysis of the AAAS gene revealed a homozygous missense mutation in exon 12. It was a T > G transversion at nucleotide position 1224, resulting in a change of leucine at amino acid position 381 into arginine (Leu381Arg or L381R). Brain appearance was found normal at magnetic resonance imaging (MRI) and functional spectroscopy analysis showed normal levels of the main metabolites. Spine MRI showed a cystic cavity within the spinal cord (syringomyelia), localized between the sixth cervical vertebra and the first thoracic vertebra. Cerebellar tonsils descended 7 mm caudal to foramen magnum, consistently with a mild type 1 Chiari malformation. Mild posterior inter-vertebral disk protrusions were evident between T9 and T10 and between L4 and L5.

To our knowledge, this is the first report describing type 1 Chiari malformation and multiple spinal cord abnormalities in a patient with Allgrove syndrome.

Stratified whole genome linkage analysis of Chiari type I malformation implicates known Klippel-Feil syndrome genes as putative disease candidates

Chiari Type I Malformation (CMI) is characterized by displacement of the cerebellar tonsils below the base of the skull, resulting in significant neurologic morbidity. Although multiple lines of evidence support a genetic contribution to disease, no genes have been identified. We therefore conducted the largest whole genome linkage screen to date using 367 individuals from 66 families with at least two individuals presenting with nonsyndromic CMI with or without syringomyelia. Initial findings across all 66 families showed minimal evidence for linkage due to suspected genetic heterogeneity. In order to improve power to localize susceptibility genes, stratified linkage analyses were performed using clinical criteria to differentiate families based on etiologic factors. Families were stratified on the presence or absence of clinical features associated with connective tissue disorders (CTDs) since CMI and CTDs frequently co-occur and it has been proposed that CMI patients with CTDs represent a distinct class of patients with a different underlying disease mechanism. Stratified linkage analyses resulted in a marked increase in evidence of linkage to multiple genomic regions consistent with reduced genetic heterogeneity. Of particular interest were two regions (Chr8, Max LOD = 3.04; Chr12, Max LOD = 2.09) identified within the subset of "CTD-negative" families, both of which harbor growth differentiation factors (GDF6, GDF3) implicated in the development of Klippel-Feil syndrome (KFS). Interestingly, roughly 3-5% of CMI patients are diagnosed with KFS. In order to investigate the possibility that CMI and KFS are allelic, GDF3 and GDF6 were sequenced leading to the identification of a previously known KFS missense mutation and potential regulatory variants in GDF6. This study has demonstrated the value of reducing genetic heterogeneity by clinical stratification implicating several convincing biological candidates and further supporting the hypothesis that multiple, distinct mechanisms are responsible for CMI.

Clinical, radiological, and genetic similarities between patients with Chiari Type I and Type 0 malformations

OBJECT

Although Chiari Type I (CM-I) and Type 0 (CM-0) malformations have been previously characterized clinically and radiologically, there have been no studies focusing on the possible genetic link between these disorders. The goal of this study was to identify families in whom CM-0 and CM-I co-occurred and to further assess the similarities between these disorders.

METHODS

Families were ascertained through a proband with CM-I. Detailed family histories were obtained to identify first-degree relatives diagnosed with CM-0. Several criteria were used to exclude individuals with acquired forms of CM-I and/or syringomyelia. Individuals were excluded with syndromic, traumatic, infectious, or tumor-related syringomyelia, as well as CM-I due to a supratentorial mass, hydrocephalus, history of cervical or cranial surgery unrelated to CM-I, or development of symptoms following placement of a lumbar shunt. Medical records and MR images were used to characterize CM-I and CM-0 individuals clinically and radiologically.

RESULTS

Five families were identified in which the CM-I proband had a first-degree relative with CM-0. Further assessment of affected individuals showed similar clinical and radiological features between CM-0 and CM-I individuals, although CM-I patients in general had more severe symptoms and skull base abnormalities than their CM-0 relatives. Overall, both groups showed improvement in symptoms and/or syrinx size following craniocervical decompression surgery.

CONCLUSIONS

There is accumulating evidence suggesting that CM-0 and CM-I may be caused by a common underlying developmental mechanism. The data in this study are consistent with this hypothesis, showing similar clinical and radiological features between CM-0 and CM-I individuals, as well as the occurrence of both disorders within families. Familial clustering of CM-0 and CM-I suggests that these disorders may share an underlying genetic basis, although additional epigenetic and/or environmental factors are likely to play an important role in the development of CM-0 versus CM-I.

Familial Chiari malformation: case series

Chiari malformations (Types I-IV) are abnormalities of the posterior fossa that affect the cerebellum, brainstem, and the spinal cord with prevalence rates of 0.1%-0.5%. Case reports of familial aggregation of Chiari malformation, twin studies, cosegregation of Chiari malformation with known genetic conditions, and recent gene and genome-wide association studies provide strong evidence of the genetic underpinnings of familial Chiari malformation. The authors report on a series of 3 family pairs with Chiari malformation Type I: 2 mother-daughter pairs and 1 father-daughter pair. The specific genetic causes of familial Chiari malformation have yet to be fully elucidated. The authors review the literature and discuss several candidate genes. Recent advances in the understanding of the genetic influences and pathogenesis of familial Chiari malformation are expected to improve management of affected patients and monitoring of at-risk family members.

Volumetric analysis of the posterior cranial fossa in a family with four generations of the Chiari malformation Type I

OBJECT

Many authors have concluded that the Chiari malformation Type I (CM-I) is due to a smaller than normal posterior cranial fossa. In order to establish this smaller geometry as the cause of hindbrain herniation in a family, the authors of this paper performed volumetric analysis in a family found to have this malformation documented in 4 generations.

METHODS

Members from this family found to have a CM-I by imaging underwent volumetric analysis of their posterior cranial fossa using the Cavalieri method.

RESULTS

No member of this family found to have CM-I on preoperative imaging had a posterior fossa that was significantly smaller than that of age-matched controls.

CONCLUSIONS

The results of this study demonstrate that not all patients with a CM-I will have a reduced posterior cranial fossa volume. Although the mechanism for the development of hindbrain herniation in this cohort is unknown, this manifestation can be seen in multiple generations of a familial aggregation with normal posterior fossa capacity.

Chiari I malformation and idiopathic growth hormone deficiency in siblings: report of three cases

INTRODUCTION

The authors report a case of three brothers.

CASE DESCRIPTIONS

Two of these siblings presented with congenital growth hormone deficiency (GHD) and Chiari I malformation (CIM). The third younger brother has been found not to have GHD or the CIM.

DISCUSSION

Sparse cases of these two clinical occurrences have been reported. Further, the posterior cranial fossa (PF) has been determined to be altered in patients with CIM and GHD.

CONCLUSION

Our current case reports strengthen the association between these two pathological entities and, to our knowledge, is the first description of both defects in siblings.

Possible genetic correlation of an occipital dermal sinus in a mother and son. Case report

Occipital dermal sinuses (ODSs) are congenital lesions located in the midline and characterized by a cutaneous pit or dimple. The intracranial extension as well as the associated symptoms are variable. To date, a familial occurrence of these lesions has not been reported. In this paper the authors report on a 2-year-old boy with an ODS and intracranial hypertension. The boy's mother had a similar lesion but did not have any complaints. Following their experience with this case and a literature review, the authors suggest that there may be a genetic basis in certain instances of ODS.

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.

Evidence of familial syringomyelia in discordant association with Chiari type I malformation

We report a sister and two half brothers who presented with magnetic resonance imaging (MRI)-proven syringomyelia and associated Chiari type I malformation in two cases. The individuals have the same mother but two different fathers. The mother shows no clinical signs of syringomyelia. The two fathers died through unknown causes. In a third healthy son of the mother by a relationship with a third father syringomyelia was excluded by MRI. We believe that an autosomal-dominant predisposition is the primary factor in the appearance of syringomyelia in these cases.

Chiari I malformation and idiopathic growth hormone deficiency in siblings

INTRODUCTION

The authors report a case of three brothers. Two of these siblings presented with congenital growth hormone deficiency and Chiari I malformation. The third and younger brother has been found not to have growth hormone deficiency or the Chiari I malformation.

RESULTS

Sparse cases of these two clinical occurrences have been reported. Further, the posterior cranial fossa has been determined to be altered in patients with Chiari I malformation and growth hormone deficiency.

CONCLUSION

Our current case reports strengthen the association between these two pathological entities and are, to our knowledge, the first description of both defects in siblings.

Chiari in the family: inheritance of the Chiari I malformation

This report presents three families with Chiari malformation type I that became symptomatic during childhood: a mother and son; a set of monozygotic twins; and two half-siblings and their two maternal cousins. These children presented with various symptoms, including headache, stiff neck, and swallowing difficulty. A review of the relevant literature is presented, with an emphasis on familial examples and proposed inheritance. Less common presentations of Chiari malformation type I are discussed, as well as the possible pathogenesis of Chiari malformation type I and associated syringomyelia.

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.