Infantile neuroaxonal dystrophy (INAD) is an autosomal recessive progressive neurodegenerative disease that presents within the first 2 years of life and culminates in death by age 10 years. Affected individuals from two unrelated Bedouin Israeli kindreds were studied. Brain imaging demonstrated diffuse cerebellar atrophy and abnormal iron deposition in the medial and lateral globus pallidum. Progressive white-matter disease and reduction of the N-acetyl aspartate : chromium ratio were evident on magnetic resonance spectroscopy, suggesting loss of myelination. The clinical and radiological diagnosis of INAD was verified by sural nerve biopsy. The disease gene was mapped to a 1.17-Mb locus on chromosome 22q13.1 (LOD score 4.7 at recombination fraction 0 for SNP rs139897), and an underlying mutation common to both affected families was identified in PLA2G6, the gene encoding phospholipase A2 group VI (cytosolic, calcium-independent). These findings highlight a role of phospholipase in neurodegenerative disorders.

We describe a maternally transmitted genomic-imprinting syndrome of mental retardation, hypotonia, and unique dysmorphism with elongated face. We mapped the disease-associated locus to approximately 7.27 Mb on chromosome 8q24 and demonstrated that the disease is caused by a missense mutation in the maternal copy of KCNK9 within this locus. KCNK9 is maternally transmitted (imprinted with paternal silencing) and encodes K(2P)9.1, a member of the two pore-domain potassium channel (K(2P)) subfamily. The mutation fully abolishes the channel's currents--both when functioning as a homodimer or as a heterodimer with K(2P)3.1.

Key Points• A novel clinical syndrome is reported which is triggered by common febrile episodes in infancy and presents with Coombs' neg hemolysis and demyelineating polyneuropathy.• A gene mutation in CD59 leading to loss of expression of CD59 on the cell surface is presented as the genetic basis for the disease.

It has recently been shown that merosin, a laminin variant, is deficient in a proportion of patients with congenital muscular dystrophy. Merosin is a heterotrimer composed of the alpha 2, beta 1, and gamma 1 subunits, and further studies have shown that it is the alpha 2 subunit that is deficient in these patients. Because the alpha 2 subunit is also expressed in S-merosin, found in Schwann cells, we have investigated whether peripheral nerve function is also affected in these patients. Motor nerve conduction velocities and sensory distal latencies were examined in 25 cases of congenital muscular dystrophy and the results correlated with the merosin expression in their muscle biopsies. All but two of the 10 merosin-deficient cases had reduced motor nerve conduction, whereas all the merosin-positive cases had normal results. Analysis of the biopsies of these two cases showed that they produced merosin in reduced amounts, in contrast to all other merosin-deficient patients that produced no or only traces of merosin. Sensory nerve studies showed no difference between the two groups. These results indicate that a peripheral demyelinating neuropathy is a feature of merosin-deficient congenital muscular dystrophy. The fact that the alpha 2 subunits is also expressed in Schwann cells supports the idea that the alpha 2 gene, located on chromosome 6, is the candidate gene for merosin-deficient congenital muscular dystrophy.

SCN9A encodes the voltage-gated sodium channel Nav1.7, a protein highly expressed in pain-sensing neurons. Mutations in SCN9A cause three human pain disorders: bi-allelic loss of function mutations result in Channelopathy-associated Insensitivity to Pain (CIP), whereas activating mutations cause severe episodic pain in Paroxysmal Extreme Pain Disorder (PEPD) and Primary Erythermalgia (PE). To date, all mutations in SCN9A that cause a complete inability to experience pain are protein truncating and presumably lead to no protein being produced. Here, we describe the identification and functional characterization of two novel non-truncating mutations in families with CIP: a homozygously-inherited missense mutation found in a consanguineous Israeli Bedouin family (Nav1.7-R896Q) and a five amino acid in-frame deletion found in a sporadic compound heterozygote (Nav1.7-ΔR1370-L1374). Both of these mutations map to the pore region of the Nav1.7 sodium channel. Using transient transfection of PC12 cells we found a significant reduction in membrane localization of the mutant protein compared to the wild type. Furthermore, voltage clamp experiments of mutant-transfected HEK293 cells show a complete loss of function of the sodium channel, consistent with the absence of pain phenotype. In summary, this study has identified critical amino acids needed for the normal subcellular localization and function of Nav1.7. © 2010 Wiley-Liss, Inc.

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Congenital insensitivity to pain with anhidrosis (CIPA), a rare and severe disorder, comprises absence of sensation to noxious stimuli, inability to sweat, and recurrent episodes of hyperthermia. It has a relatively high prevalence in the consanguineous Israeli-Bedouins. Clinical studies of 28 patients are reported here. Using the linkage analysis approach, we linked the disease in 9 of 10 unrelated Israeli-Bedouin families with CIPA to the TrkA gene, which encodes the receptor for nerve growth factor. In one family, linkage was excluded, implying that another gene, yet unidentified, is involved. Two new mutations in the tyrosine kinase domain of the TrkA gene were identified in our CIPA patients: a 1926-ins-T in most of the southern Israeli-Negev CIPA patients, and a Pro- 689-Leu mutation in a different isolate of Bedouins in northern Israel. Eight prenatal diagnoses were made in the southern Israeli-Negev Bedouins, two by linkage analysis and six by checking directly for the 1926-ins-T mutation. Three polymorphisms in the TrkA protein kinase encoding domain were also observed.

The severe refractory type of status epilepticus is very rare in the pediatric population. Eight children with the severe refractory type of status epilepticus owing to presumed encephalitis are described. The age at the onset of status epilepticus of the eight study children ranged between 2.5 and 15 years. Seven of the eight children presented with fever several days prior to the onset of seizures. A comprehensive clinical and laboratory investigation failed to delineate a cause for their seizures. Burst suppression coma was induced by pentothal, midazolam, propofol, or ketamine in all of the children. The mean duration of anesthesia was 28 days (range 4-62 days), but the seizures persisted in spite of repeated burst suppression cycles in all of them. Two children died. Four of the surviving children continued to suffer from seizures, and cognitive sequelae were present throughout follow-up in four children. In summary, the severe refractory type of status epilepticus of the acute symptomatic type owing to relatively mild encephalitis carries a high mortality rate and poor morbidity in terms of seizures and cognition at follow-up.