High Incidence of Noonan Syndrome Features Including Short Stature and Pulmonic Stenosis in Patients carrying NF1 Missense Mutations Affecting p.Arg1809: Genotype-Phenotype Correlation.

Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders, affecting 1:3,000 worldwide. Identification of genotype-phenotype correlations is challenging because of the wide range clinical variability, the progressive nature of the disorder, and extreme diversity of the mutational spectrum. We report 136 individuals with a distinct phenotype carrying one of five different NF1 missense mutations affecting p.Arg1809. Patients presented with multiple café-au-lait macules (CALM) with or without freckling and Lisch nodules, but no externally visible plexiform neurofibromas or clear cutaneous neurofibromas were found. About 25% of the individuals had Noonan-like features. Pulmonic stenosis and short stature were significantly more prevalent compared with classic cohorts (P < 0.0001). Developmental delays and/or learning disabilities were reported in over 50% of patients. Melanocytes cultured from a CALM in a segmental NF1-patient showed two different somatic NF1 mutations, p.Arg1809Cys and a multi-exon deletion, providing genetic evidence that p.Arg1809Cys is a loss-of-function mutation in the melanocytes and causes a pigmentary phenotype. Constitutional missense mutations at p.Arg1809 affect 1.23% of unrelated NF1 probands in the UAB cohort, therefore this specific NF1 genotype-phenotype correlation will affect counseling and management of a significant number of patients.

Duplication within the SEPT9 gene associated with a founder effect in North American families with hereditary neuralgic amyotrophy.

Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant disorder associated with recurrent episodes of focal neuropathy primarily affecting the brachial plexus. Point mutations in the SEPT9 gene have been previously identified as the molecular basis of HNA in some pedigrees. However in many families, including those from North America demonstrating a genetic founder haplotype, no sequence mutations have been detected. We report an intragenic 38 Kb SEPT9 duplication that is linked to HNA in 12 North American families that share the common founder haplotype. Analysis of the breakpoints showed that the duplication is identical in all pedigrees, and molecular analysis revealed that the duplication includes the 645 bp exon in which previous HNA mutations were found. The SEPT9 transcript variants that span this duplication contain two in-frame repeats of this exon, and immunoblotting demonstrates larger molecular weight SEPT9 protein isoforms. This exon also encodes for a majority of the SEPT9 N-terminal proline rich region suggesting that this region plays a role in the pathogenesis of HNA.

A novel locus for familial migraine on Xp22.

INTRODUCTION: Migraine is thought to be genetically complex. There is evidence of an X-linked dominant genetic component. A locus at Xq24-q28 has already been described supporting this hypothesis. METHODS: The X chromosome in 61 migraine families was screened using markers spanning the entire chromosome. Alleles were assigned using the GeneScan Analysis software, analysis for affected relative allele sharing and linkage was performed using Genehunter X and ALLEGRO. For linkage analysis we chose a model based on epidemiological data as well as assumptions drawn on other complex disorders. RESULTS: Linkage analysis of combined families showed a parametric 2-point logarithm of the odds (LOD) of 2.86 at theta 0.1 between markers DXS8051 and DXS1223, as well as excess allele sharing at marker DXS8051 with a non-parametric LOD score of 2.85. CONCLUSION: These results provide suggestive evidence for a susceptibility locus for migraine on Xp22. Families with different types of migraine contributed to this LOD score.

Patient-reported outcomes of pain and physical functioning in neurofibromatosis clinical trials.

OBJECTIVE: Tumors and other disease complications of neurofibromatosis (NF) can cause pain and negatively affect physical functioning. To document the clinical benefit of treatment in NF trials targeting these manifestations, patient-reported outcomes (PROs) assessing pain and physical functioning should be included as study endpoints. Currently, there is no consensus on the selection and use of such measures in the NF population. This article presents the recommendations of the PRO group of the Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration for assessing the domains of pain and physical functioning for NF clinical trials. METHODS: The REiNS PRO group reviewed and rated existing PRO measures assessing pain intensity, pain interference, and physical functioning using their systematic method. Final recommendations are based primarily on 4 main criteria: patient characteristics, item content, psychometric properties, and feasibility for clinical trials. RESULTS: The REiNS PRO group chose the Numeric Rating Scale-11 (≥8 years) to assess pain intensity, the Pain Interference Index (6-24 years) and the Patient-Reported Outcome Measurement Information System (PROMIS) Pain Interference Scale (≥18 years) to evaluate pain interference, and the PROMIS Physical Functioning Scale to measure upper extremity function and mobility (≥5 years) for NF clinical trials. CONCLUSIONS: The REiNS Collaboration currently recommends these PRO measures to assess the domains of pain and physical functioning for NF clinical trials; however, further research is needed to evaluate their use in individuals with NF. A final consensus recommendation for the pain interference measure will be disseminated in a future publication based on findings from additional published research.

Physical mapping and characterization of the human Na,K-ATPase isoform, ATP1A4.

Four isoforms of the catalytic alpha subunit of the Na,K-ATPase have been previously identified. We characterized and mapped a genomic copy of the human ATP1A4 isoform between D1S2707 and WI-9524, telomeric to a nearby isoform ATP1A2, and within a candidate region at 1q23 for familial hemiplegic migraine (FHM). Human ATP1A4 gene shares 84% identity with the mouse Atp1a4 gene, and both consist of 22 exons and 21 introns. The predicted polypeptide is 1029 amino acids and shares 82 and 79.8% identity, respectively, with human ATP1A2 and ATP1A1. ATP1A4 is larger than other isoforms and most divergent at the N-terminus. ATP1A4 and ATP1A2 are paralogous genes with the same number and organization of putative H-transmembrane domains, conserved exon-intron boundaries, and are found approximately 8.5 kb apart. Expression analysis of the ATP1A4 gene revealed a new major approximately 7.5 kb transcript in human skeletal muscle, with expression also shown in mouse muscle. Predictive analysis of promoter regions identified muscle specific regulatory elements for ATP1A4 and Atp1a4. Mutation analysis among eight affected individuals from a single large, highly penetrant FHM family was negative in ATP1A4 and ATP1A2 although multiple polymorphisms were identified.

Germline loss-of-function mutations in LZTR1 predispose to an inherited disorder of multiple schwannomas.

Constitutional SMARCB1 mutations at 22q11.23 have been found in ∼50% of familial and <10% of sporadic schwannomatosis cases. We sequenced highly conserved regions along 22q from eight individuals with schwannomatosis whose schwannomas involved somatic loss of one copy of 22q, encompassing SMARCB1 and NF2, with a different somatic mutation of the other NF2 allele in every schwannoma but no mutation of the remaining SMARCB1 allele in blood and tumor samples. LZTR1 germline mutations were identified in seven of the eight cases. LZTR1 sequencing in 12 further cases with the same molecular signature identified 9 additional germline mutations. Loss of heterozygosity with retention of an LZTR1 mutation was present in all 25 schwannomas studied. Mutations segregated with disease in all available affected first-degree relatives, although four asymptomatic parents also carried an LZTR1 mutation. Our findings identify LZTR1 as a gene predisposing to an autosomal dominant inherited disorder of multiple schwannomas in ∼80% of 22q-related schwannomatosis cases lacking mutation in SMARCB1.

Stroke following epidural injections--case report and review of literature.

BACKGROUND AND PURPOSE: To describe a growing number of cases associated with spinal cord and posterior circulation ischemia as a complication of cervical epidural steroid injection (CESI). METHODS: Case report and review of literature. RESULTS: Sixteen cases of spinal cord and posterior circulation ischemia were analyzed. Two cases had transient symptoms and 10 had long-term sequelae. Four resulted in death. CONCLUSION: Infarction is a rare but potentially devastating complication of CESI. It may occur despite the use of fluoroscopic guidance.

Patient-reported outcomes in neurofibromatosis and schwannomatosis clinical trials.

OBJECTIVES: Neurofibromatosis (NF) is a genetic disease with multiple clinical manifestations that can significantly impact quality of life (QOL). Clinical trials should include patient-reported outcomes (PROs) as endpoints to assess treatment effects on various aspects of QOL, but there is no consensus on the selection and use of such measures in NF. This article describes the PRO Working Group of the Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) Collaboration, its main goals, methods for identifying appropriate PRO measures for NF clinical trials, and recommendations for assessing pain intensity. METHODS: The REiNS PRO group selected core endpoint domains important to assess in NF. The members developed criteria to rate PRO measures, including patient characteristics, psychometric properties, and feasibility, and utilized a systematic process to evaluate PROs for NF clinical trials. Within the subdomain of pain intensity, the group reviewed the Numerical Rating Scale-11 (NRS-11), the Visual Analogue Scale, and the Faces Pain Scale-Revised using this process. RESULTS: Based on the review criteria, each of these pain intensity scales is brief, reliable, valid, and widely used. However, the NRS-11 was given the highest rating for use in NF clinical trials due to recommendations from pain experts and other consensus groups, its extensive use in research, strong psychometric data including sensitivity to change, and excellent feasibility in ages ≥ 8 years. CONCLUSIONS: The systematic review criteria and process are effective for identifying appropriate PRO measures and provide information utilized by the REiNS Collaboration to achieve consensus regarding PROs in NF clinical trials.

Genetics of migraine: an update.

Observations including the long-recognized tendency of migraine to run in families, the high concordance rates for migraine in twins reared together or apart, and the association of specific mutations with a rare migraine form are consistent with a genetic contribution to the disorder. This paper summarizes major findings to date on the genetics of migraine. Study of the heritability of migraine, particularly the common forms of migraine, is beset by several challenges including the absence of easily measurable biological markers, uncertainty about the etiologic and clinical overlap among migraine types, and the apparently complex interplay of environmental and genetic factors in determining migraine phenotype. Nevertheless, significant progress has been realized in recent years. Familial hemiplegic migraine, a rare migraine variant, appears to be transmitted by a Mendelian, autosomal dominant mode of inheritance involving mutations in at least 2 genes. These genes do not seem to be critically involved in the other forms of migraine; however, several other susceptibility loci for more common forms of migraine have been identified in recent genome-wide screens and candidate-locus studies. These and other data suggest that the genetic contribution to migraine is complex, multifactorial, and subject to significant modification by environmental factors.

Both insulin and calcium channel signaling are required for developmental regulation of serotonin synthesis in the chemosensory ADF neurons of Caenorhabditis elegans.

Proper calcium channel and insulin signaling are essential for normal brain development. Leaner mice with a mutation in the P/Q-type voltage-gated calcium channel, Cacna1a, develop cerebellar atrophy and mutations in the homologous human gene are associated with increased migraine and seizure tendency. Similarly, abnormalities in insulin signaling are associated with abnormal brain growth and migraine tendency. Previously, we have shown that in the ADF chemosensory neurons of Caenorhabditis elegans UNC-2/Ca(2+) channel function affects TGF-beta-dependent developmental regulation of tryptophan hydroxylase, the rate-limiting enzyme in serotonin synthesis. Here we show that developmental expression of a tryptophan hydroxylase: :GFP reporter construct is similarly decreased by reduction-of-function mutations in the daf-2/insulin receptor. This decreased expression of tryptophan hydroxylase observed in both the daf-2 and unc-2 mutant backgrounds is suppressible either genetically by reduction-of-function mutations in the daf-16/forkhead transcription factor, an effector of the DAF-2/insulin receptor, or pharmacologically by the serotonin receptor antagonist cyproheptadine. Overall, these data suggest that both UNC-2 and DAF-2 function are required in the developmental regulation of DAF-16 and serotonin-dependent inhibition of tryptophan hydroxylase expression.

Update on the genetics of migraine.

The field of migraine genetics has seen an explosion of information over the last year. In a recent breakthrough, missense mutations in a chromosome 1q23 gene, ATP1A2, encoding a Na+, K+-ATPase, have been identified in four distinct pedigrees with a rare form of familial hemiplegic migraine (FHM). ATP1A2 is expressed in the brain, like the voltage gated calcium channel gene, CACNA1A, previously identified as the first hemiplegic migraine gene (FHM1). The shared hemiplegic migraine phenotype of mutations in ATP1A2 and CACNA1A raises the possibility that they coordinately regulate ion homeostasis that determines susceptibility to the initiation of both migraine aura and the pain phase of migraine. For the more common and genetically complex forms of migraine, genome-wide screens have identified several new loci on 4q24, 6p12.2-21.1, 11q24, and 14q21.2-q22.3, suggesting additional migraine genes in these regions. In addition, a recent large case-control association study has linked single nucleotide polymorphisms in the insulin receptor/INSR gene with migraine. However, these polymorphisms do not result in detectable changes in receptor function. The continuing genetic identification of key proteins involved in migraine will refine our understanding of this common and sometimes debilitating disorder, which can strike during the most productive years of a person's life. Given the co-morbidity of migraine with depression and bipolar disorder, our knowledge of the causes of migraine may also contribute to our understanding of these disorders.

The voltage-gated calcium channel UNC-2 is involved in stress-mediated regulation of tryptophan hydroxylase.

Migraine is an episodic pain disorder whose pathophysiology is related to deficiency of serotonin signaling and abnormal function of the P/Q-type calcium channel, CACNA1A. Because the relationship of the CACNA1A channel to serotonin signaling is unknown and potentially of therapeutic interest we have used genetic analysis of the Caenorhabditis elegans ortholog of this calcium channel, UNC-2, to help identify candidate downstream effectors of the human channel. By genetic dissection of the lethargic mutant phenotype of unc-2, we have established an epistasis pathway showing that UNC-2 function antagonizes a transforming growth factor (TGF)-beta pathway influencing movement rate. This same UNC-2/TGF-beta pathway is required for accumulation of normal serotonin levels and stress-induced modulation of tryptophan hydroxylase (tph) expression in the serotonergic chemosensory ADF neurons, but not the NSM neurons. We also show that transgenic expression of the migraine-associated Ca2+ channel, CACNA1A, in unc-2 animals can functionally substitute for UNC-2 in stress-activated regulation of tph expression. The demonstration that these evolutionarily related channels share a conserved ability to modulate tph expression through their effects on TGF-beta signaling provides the first specific example of how CACNA1A function may influence levels of the critical migraine neurotransmitter serotonin.

Spinocerebellar ataxia type 8: molecular genetic comparisons and haplotype analysis of 37 families with ataxia.

We reported elsewhere that an untranslated CTG expansion causes the dominantly inherited neurodegenerative disorder spinocerebellar ataxia type 8 (SCA8). SCA8 shows a complex inheritance pattern with extremes of incomplete penetrance, in which often only one or two affected individuals are found in a given family. SCA8 expansions have also been found in control chromosomes, indicating that separate genetic or environmental factors increase disease penetrance among SCA8-expansion-carrying patients with ataxia. We describe the molecular genetic features and disease penetrance of 37 different families with SCA8 ataxia from the United States, Canada, Japan, and Mexico. Haplotype analysis using 17 STR markers spanning an approximately 1-Mb region was performed on the families with ataxia, on a group of expansion carriers in the general population, and on psychiatric patients, to clarify the genetic basis of the reduced penetrance and to investigate whether CTG expansions among different populations share a common ancestral background. Two major ancestrally related haplotypes (A and A') were found among white families with ataxia, normal controls, and patients with major psychosis, indicating a common ancestral origin of both pathogenic and nonpathogenic SCA8 expansions among whites. Two additional and distinct haplotypes were found among a group of Japanese families with ataxia (haplotype B) and a Mexican family with ataxia (haplotype C). Our finding that SCA8 expansions on three independently arising haplotypes are found among patients with ataxia and cosegregate with ataxia when multiple family members are affected further supports the direct role of the CTG expansion in disease pathogenesis.