A Novel Splice-site Mutation on the MLC1 Gene Leading to Exon 9 Skipping and Megalencephalic Leukoencephalopathy with Subcortical Cysts in a Turkish Patient.

Megalencephalic leukoencephalopathy (MLC) with subcortical cysts, also known as Van der Knaap disease (MIM #604004) is an autosomal recessive neurological disorder characterized by early onset macrocephaly, epilepsy, neurological deterioration with cerebellar ataxia and spasticity. An 8-month-old boy was admitted to our pediatric neurology clinic with macrocephaly. His brain magnetic resonance imaging (MRI) revealed bilateral, diffuse, symmetric structural white matter abnormalities, relatively sparing the cerebellum and bilateral subcortical temporal cysts. The diagnosis of Van der Knaap disease was suspected based on the clinical features and imaging findings and the genetic analysis revealed a novel homozygous c.768+2T>C mutation of the MLC1 gene. For determination of the novel splice-site mutation's effect, cDNA amplification was performed. cDNA analysis showed that the splice-site c.768+2T>C mutation gave rise to exon 9 skipping.

CLINICAL REPORT OF A PATIENT WITH DE NOVO TRISOMY 12q23.1q24.33.

We report a patient with a rare de novo duplication of 12q23.1-12q24.33 region with a 32.7 Mb gain, having similar features seen in previously reported isolated cases of duplications of the 12q23q24 region, such as growth retardation, neuromotor retardation, corpus callosum agenesis, dysmorphic features such as, hypertelorism, epicanthus, flat nasal bridge, low-set small ears, down-turned corners of the mouth, micrognathia, cryptorchidism and limb anomalies such as pes plano valgus, prominent heels and overriding toes. Our patient has Noonan-like features, such as short stature, short neck, epicanthal folds, ptosis of eyelids, hypertelorism, pectus excavatum, widely spaced nipples and cryptorchidism. Duplication of PTPN11 gene has been postulated as a mechanism for the Noonan syndrome. Phenotypic features and the genes involved in this region are important to further delineate the 12q23q24 phenotype.

Evaluation of vestibular functions in children with vertigo attacks.

AIM: To examine vestibular system functions in children with episodic vertigo attacks. METHODS: Thirty four children (20 males) aged 4-18 years with paroxysmal dizziness and/or vertigo attacks were evaluated. A medical history for vestibular symptoms and migraine was taken. Vestibular and auditory functions were assessed. RESULTS: Chronic headache attacks consistent with migraine were reported in 12 children and motion sickness was reported in 30. Family history in first degree relatives was positive for migraine in 29 children and for episodic vertigo in 22. Electronystagmography and videonystagmography showed two types of nystagmus: spontaneous vestibular nystagmus (41%) and benign paroxysmal positional nystagmus (BPPN) (59%). The first type of nystagmus was assessed as a sign of vestibulopathy and the patients with BPPN were diagnosed as having benign paroxysmal positional vertigo (BPPV). Audiometric examination in four cases revealed bilateral sensory neural hearing loss in low frequencies. Pure tone averages in 30 cases were within normal ranges; however low frequencies in 28 of them were approximately 10 dB lower than high frequencies. Unilateral caloric responses diminished in eight children. CONCLUSIONS: Peripheral vestibular problems in childhood present in a wide spectrum, which varies from a short episode of dizziness to a typical vestibular attack with fluctuating sensory neural hearing loss or episodes of BPPV. A considerable number of these vestibular problems might be related to the migraine syndrome.

Phenytoin toxicity with mandibular tremor secondary to intravenous administration.

The parenteral form of phenytoin is the most commonly used antiepileptic agent during the perioperative period in neurosurgery clinics. We report observations in a 52-year-old male patient with hypoalbuminemia and phenytoin intoxicity following 1 day preoperative administration and a 7-day postoperative intravenous administration of the drug with no modification of the oral dose. This report emphasizes the need for careful surveillance of phenytoin-induced toxicity during parenteral therapy, especially in debilitated patients.

Continuous muscle fiber activity syndrome.

A 5.5 year old Turkish boy who suffered from progressive muscle stiffness was diagnosed as having continuous muscle fiber activity syndrome. Electromyography showed continuous motor neuron activity at rest and following intravenous injection of diazepam. Peripheral nerve block, spinal and general anesthesia diminished the spontaneous activities. The clinical and electrophysiological findings of our case were compared to the previously reported cases with emphasis on the heterogeneity of the syndrome.