Bilateral frontoparietal polymicrogyria: clinical and radiological features in 10 families with linkage to chromosome 16.
Polymicrogyria is a common malformation of cortical development characterized by an excessive number of small gyri and abnormal cortical lamination. Multiple syndromes of region-specific bilateral symmetric polymicrogyria have been reported. We previously have described two families with bilateral frontoparietal polymicrogyria (BFPP), an autosomal recessive syndrome that we mapped to a locus on chromosome 16q12-21. Here, we extend our observations to include 19 patients from 10 kindreds, all linked to the chromosome 16q locus, allowing us to define the clinical and radiological features of BFPP in detail. The syndrome is characterized by global developmental delay of at least moderate severity, seizures, dysconjugate gaze, and bilateral pyramidal and cerebellar signs. Magnetic resonance imaging demonstrated symmetric polymicrogyria affecting the frontoparietal regions most severely, as well as ventriculomegaly, bilateral white matter signal changes, and small brainstem and cerebellar structures. We have refined our genetic mapping and describe two apparent founder haplotypes, one of which is present in two families with BFPP and associated microcephaly. Because 11 of our patients initially were classified as having other malformations, the syndrome of BFPP appears to be more common than previously recognized and may be frequently misdiagnosed.
Chang
Bernard S
BS
Division of Neurogenetics, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, Boston, MA 02115, USA. bchang@caregroup.harvard.edu
Piao
Xianhua
X
Bodell
Adria
A
Basel-Vanagaite
Lina
L
Straussberg
Rachel
R
Dobyns
William B
WB
Qasrawi
Bassam
B
Winter
Robin M
RM
Innes
A Micheil
AM
Voit
Thomas
T
Grant
P Ellen
PE
Barkovich
A James
AJ
Walsh
Christopher A
CA
D000293:Adolescent; D000328:Adult; D001933:Brain Stem / Q000002:abnormalities; D002531:Cerebellum / Q000002:abnormalities; D002552:Cerebral Ventricles / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics*; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology; D004252:DNA Mutational Analysis; D003951:Diagnostic Errors; D005260:Female; D005625:Frontal Lobe / Q000002:abnormalities*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008831:Microcephaly / Q000150:complications / Q000235:genetics / Q000473:pathology; D015835:Ocular Motility Disorders / Q000453:epidemiology / Q000209:etiology; D010296:Parietal Lobe / Q000002:abnormalities*; D010375:Pedigree; D017354:Point Mutation / Q000235:genetics; D012640:Seizures / Q000453:epidemiology / Q000209:etiology; D012720:Severity of Illness Index; D013577:Syndrome