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Developmental Diseases of the Nervous System
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
James H. Tonsgard, Nikolas Mata-Machado
In classical lissencephaly or type 1 lissencephaly, the brain is nearly devoid of gyri and the cortical mantle is thickened (pachygyria) (Figure 9.24). The brain therefore has a smooth surface due to the absence or near absence of gyri. Microscopically, the brain lacks the normal six-layered structure of the cortex. A variety of disorders are associated with this appearance.
Paper 4
Published in Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw, The Final FRCR, 2020
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw
Lissencephaly is an abnormally smooth brain surface. The cortex is thickened and the lateral ventricles may be dilated, especially posteriorly. The cerebellum is usually not affected. Pachygyria (broad gyri) and agyria (no gyri) also exist as subtypes within this spectrum of disorders.
Neonatal adrenoleukodystrophy/disorders of peroxisomal biogenesis
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
In the presence of defective processing of peroxisomal matrix proteins, these enzymes are found in the cytosol, where some, such as the oxidase and thiolase, are degraded rapidly, while catalase accumulates and is degraded more slowly than in normal cells [85]. Among the consequences of defective peroxisomal assembly is a variety of abnormalities of morphogenesis. These are most notable externally in Zellweger syndrome, but abnormal neuronal migration takes place in neonatal ALD, as well as Zellweger syndrome [85, 86]. Abnormal migration is demonstrable in fetal tissue. Neurons normally found in the outer layers of the cerebral cortex are found in inner layers and in the white matter. Abnormal migration leads to microgyria and to thick pachygyria. Abnormal migration is not seen in rhizomelic chondrodysplasia punctata, and other peroxisomal disorders in which plasmalogen synthesis is defective, so this could not be the mechanism of the abnormal migration. On the other hand, VLCFA do not accumulate in the chondrodysplasias, so this could be involved in the abnormal neuronal pathogenesis [86]. Deficiency of plasmalogens makes cells sensitive to ultraviolet irradiation [87].
Diffusion tensor imaging and auditory tractography to evaluate cochlear implant candidacy: a pilot study
Published in Acta Oto-Laryngologica, 2023
Badr E. Mostafa, Yasser Abdel Azim, Lobna Elfiky
R.A. 9 years old girl with fluctuating hearing loss. Radiology revealed bilateral IP 2 inner ear anomaly. Tractography was performed to select the most suitable side to implant. Cochlear nerves [CN], cochlear nuclei, SOC (superior olivary complex), LL (lateral lemniscus), IC (inferior colliculus), MGB (medial geniculate body), and thalamic nuclei were all normal bilaterally. Heschel gyrus on the right side showed focal cortical dysplasia with pachygyria and polymicrogyria. Because of her residual hearing, functional MRI was performed and revealed robust activation of Heschel gyrus and area 41 on the left side and significantly reduced activation on the right side. The right CN showed reduced FA and elevated ADC. The left side was implanted with a very satisfactory result (Figure 1).
Hypoplasia of the Corpus Callosum: A Single Center Experience and a Concise Literature Review
Published in Fetal and Pediatric Pathology, 2021
Valentina D'Ambrosio, Chiara Boccherini, Lucia Manganaro, Pierluigi Benedetti Panici, Raffaella Cellitti, Flaminia Vena, Cristina Pajno, Sara Corno, Roberto Brunelli, Antonella Giancotti
A 32-years old woman G2P1 was admitted to our high-risk pregnancy unit at 35 weeks of gestation. Her past medical history was unremarkable. The first-trimester US screening and the mid-trimester anomaly scan were normal. The US scan performed at 35 weeks of gestation highlighted a unilateral borderline ventriculomegaly, a thin CC and elevated amniotic fluid levels (CC width: 4.8 mm). Genetic counseling was offered, but she refused amniocentesis and therefore no fetal karyotype was obtained. For a better evaluation a fetal brain MRI was also performed at 36 weeks of gestation. US findings were confirmed and a pachygyria was also described. A cesarean section at 39 weeks of gestation was performed due to breech presentation. A live boy in good general condition was delivered (the weight was 2798 gr, Apgar 9-10 at 1 and 5 minutes, respectively). The postnatal US and MRI evaluation confirmed the antenatal diagnosis. The six months neurological examination was normal although the ultrasound and clinical follow-up highlighted a head circumference smaller than expected (Figure 2). At 1 year, the child did not reach the developmental milestones expected for age: he does not sit or stand unassisted and does not walk with assistance.
A novel variant in DOCK6 gene associated with Adams–Oliver syndrome type 2
Published in Ophthalmic Genetics, 2020
Tariq Alzahem, Abrar K. Alsalamah, Marco Mura, Sulaiman M. Alsulaiman
Central nervous system involvement is common in patients with AOS. Out of 16 cases with AOS type 2, 11 (69%) had associated brain anomalies (19). These anomalies include microcephaly, encephalocele, and neuronal migration defects such as pachygyria and polymicrogyria. Periventricular calcifications were related to a possible preceding vascular insult and intellectual deficits usually occur in the presence of microcephaly or other structural anomalies (19). Our patient had microcephaly, periventricular calcifications, mild lateral ventricular enlargement, truncal hypotonia, and global developmental delay that were most likely attributed to AOS type 2. Congenital heart defects were reported in 31% of patients but our patient was not found to have any (19). Others systemic features include cutis marmorata telangiectatica congenita, pulmonary vein stenosis, and portal hypertension (13).