Isolated focal cortical dysplasia type IIb

General Information (adopted from Orphanet):

Synonyms, Signs: CORTICAL DYSPLASIA OF TAYLOR
CORTICAL DYSPLASIA OF TAYLOR WITHOUT BALLOON CELLS, INCLUDED
CDTD, INCLUDED
FOCAL CORTICAL DYSPLASIA OF TAYLOR, TYPE IIB, INCLUDED
CORTICAL DYSPLASIA OF TAYLOR, DYSPLASIA ONLY, INCLUDED
FOCAL CORTICAL DYSPLASIA, TYPE II FOCAL CORTICAL DYSPLASIA OF TAYLOR, TYPE IIA, INCLUDED
CDTBC, INCLUDED
CORTICAL DYSPLASIA OF TAYLOR WITH BALLOON CELLS, INCLUDED
FCDT
CDT
FCD type IIb
Number of Symptoms 19
OrphanetNr: 269008
OMIM Id: 607341
ICD-10: Q04.8
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Sporadic
[Omim]
Age of onset: Adult onset
Infantile onset
[Omim]

Disease classification (adopted from Orphanet):

Parent Diseases: Isolated focal cortical dysplasia type II
 -Rare developmental defect during embryogenesis
 -Rare genetic disease
 -Rare neurologic disease

Symptom Information: Sort by abundance 

1
 (HPO:0001249) Intellectual disability 1089 / 7739
2
 (OMIM) MRI may be normal, especially in type IIB 4 / 7739
3
 (OMIM) Multifocal areas of laminar dysmorphic neurons (in type IIA) 4 / 7739
4
 (OMIM) Impaired cognition 4 / 7739
5
 (OMIM) Biopsy in both types shows neuronal cytomegaly (large, bizarre, maloriented neurons) in the laminar cortex 4 / 7739
6
 (OMIM) Blurring of the gray-white junction (in type IIB) 4 / 7739
7
 (HPO:0007042) Focal white matter lesions 7 / 7739
8
 (OMIM) Absence of balloon cells (in type IIA) 4 / 7739
9
 (OMIM) Seizures, severe, drug-resistant, intractable 4 / 7739
10
 (OMIM) Focal thickening of the cortex on MRI (in type IIB) 4 / 7739
11
 (OMIM) Diffuse fibrillar astrocytosis (in type IIB) 4 / 7739
12
 (OMIM) Increased white matter abnormalities on T2 signalling (in type IIB) 4 / 7739
13
 (OMIM) Seizures occur multiple times per day 4 / 7739
14
 (OMIM) Balloon cells (in type IIB) 4 / 7739
15
 (OMIM) Focal neurologic deficits 5 / 7739
16
 (OMIM) Complex partial seizures, often with secondary generalization, are the most common type 4 / 7739
17
 (OMIM) Blurry cortical-white matter junction due to spillover of abnormal neurons (in type IIB) 4 / 7739
18
 (OMIM) Disorganized cortical architecture 4 / 7739
19
 (OMIM) Funnel-shaped signal tapering from subcortical white matter to ventricle (in some type IIB patients) 4 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Cortical dysplasia of Taylor is a cerebral developmental malformation that results in a clinical phenotype of intractable epilepsy usually requiring surgery. FCDT has been classified histologically into 2 subtypes: a type without balloon cells, known as type IIA, ...
Clinical Description OMIM Taylor et al. (1971) reported distinctive neuropathologic findings in 10 patients undergoing surgery for refractory epilepsy described as 'masses of large aberrant neurons littered apparently in chaos through all but the first molecular layer.' In 7 of the ...
Molecular genetics OMIM Becker et al. (2002) did a mutation screen of the TSC1 and TSC2 (191092) genes in 48 patients with chronic focal epilepsy and histologically documented focal cortical dysplasia of Taylor type IIB. Sequence alterations (e.g., 605284.0007) resulting in ...