Genetic and phenotypic characterization of NKX6-2-related spastic ataxia and hypomyelination.

BACKGROUND AND PURPOSE: Hypomyelinating leukodystrophies are a heterogeneous group of genetic disorders with a wide spectrum of phenotypes and a high rate of genetically unsolved cases. Bi-allelic mutations in NKX6-2 were recently linked to spastic ataxia 8 with hypomyelinating leukodystrophy. METHODS: Using a combination of homozygosity mapping, exome sequencing, and detailed clinical and neuroimaging assessment a series of new NKX6-2 mutations in a multicentre setting is described. Then, all reported NKX6-2 mutations and those identified in this study were combined and an in-depth analysis of NKX6-2-related disease spectrum was provided. RESULTS: Eleven new cases from eight families of different ethnic backgrounds carrying compound heterozygous and homozygous pathogenic variants in NKX6-2 were identified, evidencing a high NKX6-2 mutation burden in the hypomyelinating leukodystrophy disease spectrum. Our data reveal a phenotype spectrum with neonatal onset, global psychomotor delay and worse prognosis at the severe end and a childhood onset with mainly motor phenotype at the milder end. The phenotypic and neuroimaging expression in NKX6-2 is described and it is shown that phenotypes with epilepsy in the absence of overt hypomyelination and diffuse hypomyelination without seizures can occur. CONCLUSIONS: NKX6-2 mutations should be considered in patients with autosomal recessive, very early onset of nystagmus, cerebellar ataxia with hypotonia that rapidly progresses to spasticity, particularly when associated with neuroimaging signs of hypomyelination. Therefore, it is recommended that NXK6-2 should be included in hypomyelinating leukodystrophy and spastic ataxia diagnostic panels.

Intracranial extraosseous chondroblastoma simulating meningioma.

Extraosseous chondroblastoma had been reported in different parts of the body but not intracranially. We report a case of a pathologically proven intracranial extraosseous chondroblastoma of the right cavernous sinus in an 18-year-old woman with CT, MR, and conventional angiographic features simulating meningioma.

Temporal dermoid cyst with a partial dermal sinus tract.

BACKGROUND: Cranial dermal sinuses are rare and occur most frequently in the posterior fossa and along the midline. Likewise, supratentorial dermoid cysts are very uncommon. METHOD: We report a unique case of an adult female patient with both a supratentorial dermoid cyst and an incomplete dermal sinus tract. RESULTS: The patient is a 31-year-old female, who presented with a new onset complex partial seizure. Neuroimaging and surgery revealed a right superior temporal dermoid cyst with an associated dermal sinus tract. Furthermore, the dermal sinus tract was incomplete and had no cutaneous manifestations. CONCLUSION: We present a rare patient with an off midline supratentorial dermoid cyst associated with a uniquely incomplete cranial dermal sinus tract. The dermal sinus tract involved the bone, dura and intradural compartment, without involving the overlying skin. This represents a novel variant in the spectrum of cranial dermal sinus abnormalities.

Sequestrated meningocele of the scalp.

A case of occipital sequestrated (rudimentary) meningocele in a 2-year-old girl is presented. The swelling was noticed at birth and did not grow over time. The skull radiograph showed no bone defect and ultrasound and computed tomography examinations demonstrated cystic mass with no connection to dura. The aim of this report is to draw the attention of radiology literature readers to this entity and to elaborate on the role of imaging in the preoperative assessment of such cases. The relation of sequestrated meningocele to the other conditions with ectopic meningeal tissue in the scalp is addressed.

Introduction of skull bone fragments into the brain during external ventricular drain placement.

OBJECTIVE: To report an observation of small high attenuation foci in the tract of external ventricular drain on computed tomographic (CT) scan after removal of the drain and propose an explanation for this observation. METHODS: Six patients with small high attenuation foci in the ventricular drain tract seen on CT after removal of the drain were retrospectively identified. The CT studies before, during, and after ventricular drainage were reviewed for the size, shape, location, and time of appearance of these foci. RESULTS: In all patients, the high attenuation foci in the drain's tract were identified on CT done within 24 h from removal of the drain. In one patient, the high attenuation focus was seen adjacent to the drain on the CT obtained while the drain was in place. The high attenuation foci maintained constant size and shape on serial follow-up CT, and had variable location along the drain's tract. None of the patients developed symptoms related to these foci. CONCLUSION: Small bone pieces from the calvarium after drilling for external ventricular drain can inadvertently be pushed into the brain parenchyma during drain insertion. Early identification of these pieces on CT after removal of the drain and their constant size and shape are the clues for their nature. Temporal evolution of CT findings does not support the possibility of calcification in a small infarction or hematoma in the tract of the drain.

MRI features of epidural extramedullary hematopoiesis.

A case of beta-thalassemia intermedia with spinal cord compression due to extramedullary hematopoiesis, which was successfully treated by blood transfusion, is presented. Emphasis was made on the MRI appearance of extramedullary hematopoiesis on different pulse sequences. The theories that aimed to explain the involvement of the epidural space by extramedullary hematopoiesis are discussed.

Pai syndrome: a report of a case and review of the literature.

Pai syndrome is a rare congenital disorder first described in 1987. The main clinical features of the syndrome include median cleft of the upper lip, intra-cranial lipoma, and cutaneous polyps. Only four cases have been described previously. This is the fifth who is a twin of Arabian descent to be reported. Full description of the clinico-pathological features and a review of the relevant medical literature is presented. To the best of our knowledge, this is the first case of Pai syndrome in a twin in the English literature.

Clinical characterization of the HOXA1 syndrome BSAS variant.

BACKGROUND: The Bosley-Salih-Alorainy syndrome (BSAS) variant of the congenital human HOXA1 syndrome results from autosomal recessive truncating HOXA1 mutations. We describe the currently recognized spectrum of ocular motility, inner ear malformations, cerebrovascular anomalies, and cognitive function. METHODS: We examined nine affected individuals from five consanguineous Saudi Arabian families, all of whom harbored the same I75-I76insG homozygous mutation in the HOXA1 gene. Patients underwent complete neurologic, neuro-ophthalmologic, orthoptic, and neuropsychological examinations. Six individuals had CT, and six had MRI of the head. RESULTS: All nine individuals had bilateral Duane retraction syndrome (DRS) type 3, but extent of abduction and adduction varied between eyes and individuals. Eight patients were deaf with the common cavity deformity of the inner ear, while one patient had normal hearing and skull base development. Six had delayed motor milestones, and two had cognitive and behavioral abnormalities meeting Diagnostic and Statistical Manual of Mental Disorders-IV criteria for autism spectrum disorder. MRI of the orbits, extraocular muscles, brainstem, and supratentorial brain appeared normal. All six appropriately studied patients had cerebrovascular malformations ranging from unilateral internal carotid artery hypoplasia to bilateral agenesis. CONCLUSIONS: This report extends the Bosley-Salih-Alorainy syndrome phenotype and documents the clinical variability resulting from identical HOXA1 mutations within an isolated ethnic population. Similarities between this syndrome and thalidomide embryopathy suggest that the teratogenic effects of early thalidomide exposure in humans may be due to interaction with the HOX cascade.

Cerebral bleeding, infarcts, and presumed extrapontine myelinolysis in hypernatraemic dehydration.

The neuroimaging findings in an infant with hypernatremic dehydration are presented. Brain parenchymal haemorrhage and extensive multiple infarcts were present in the acute stage. Follow-up CT showed bilateral, symmetrical changes presumed to indicate extrapontine myelinolysis in the thalamus and globus pallidus. MRI confirmed sparing of the pons. Only three previous cases of neuroimaging abnormalities due to hypernatraemia have been described in the radiological literature.

Cree leukoencephalopathy: neuroimaging findings.

PURPOSE: To describe the computed tomographic (CT) and magnetic resonance (MR) imaging findings in Cree leukoencephalopathy. MATERIALS AND METHODS: The authors retrospectively reviewed the medical records and neuroimaging studies in 12 infants with Cree leukoencephalopathy (CT in 12 infants, MR in six). The diagnosis was established clinically in six patients and at autopsy in the other six. RESULTS: At CT, extensive, diffuse, and symmetric hypoattenuation was seen in the cerebral and cerebellar white matter in all 12 patients. Hypoattenuation was also seen in the corpus callosum in 11 (92%), internal capsule in 10 (83%), globus pallidus in nine (75%), brainstem in nine (75%), and thalamus in four (33%). The caudate nucleus and putamen were spared. On T2-weighted MR images in six patients, the cerebral and cerebellar white matter, including the subcortical arcuate fibers, was hyperintense as were the internal capsule, corpus callosum, corticospinal tracts, and globus pallidus. The thalamus was affected in four (67%) patients, pons in five (83%), and medulla in four (33%). The caudate nucleus and putamen were not affected. CONCLUSION: Cree leukoencephalopathy causes striking symmetric and diffuse involvement of the cerebral and cerebellar white matter and brainstem with sparing of the caudate nucleus and putamen.