Journal of Pediatric Neurology 2024; 22(05): 396-406
DOI: 10.1055/s-0044-1786782
Review Article

Anomalies of Midbrain/Hindbrain Development and Related Disabilities: Pontocerebellar Hypoplasia, Congenital Disorders of Glycosylation, and Cerebellar Hemisphere Hypoplasia

Alessandro Gulino*
1   Pediatrics Postgraduate Residency Program, University of Catania, Catania, Italy
,
Federica Dierna*
1   Pediatrics Postgraduate Residency Program, University of Catania, Catania, Italy
,
Antonio Zanghì*
2   Department of Medical and Surgical Sciences and Advanced Technologies, Research Center for Surgery of Complex Malformation Syndromes of Transition and Adulthood, University of Catania, Catania, Italy
,
Michele Vecchio
3   Department of Biomedical and Biotechnological Sciences, Rehabilitation Unit, University of Catania, Catania, Italy
,
Stefania Salafia
4   Unit of Pediatrics, Lentini Hospital, Lentini, Italy
,
Francesco Marino
5   Department of Medical Surgical Sciences and Advanced Technologies, University Hospital Policlinico “G. Rodolico-San Marco”, Catania, Italy
,
Pietro Foti
6   Department of Medical Surgical Sciences and Advanced Technologies, Unit of Radiology 1, University Hospital Policlinico “G. Rodolico-San Marco”, Catania, Italy
,
Giuseppe Belfiore
6   Department of Medical Surgical Sciences and Advanced Technologies, Unit of Radiology 1, University Hospital Policlinico “G. Rodolico-San Marco”, Catania, Italy
,
Antonio Basile
6   Department of Medical Surgical Sciences and Advanced Technologies, Unit of Radiology 1, University Hospital Policlinico “G. Rodolico-San Marco”, Catania, Italy
,
Martino Ruggieri
7   Department of Clinical and Experimental Medicine, Unit of Clinical Pediatrics, University of Catania, Catania, Italy
,
Agata Polizzi
8   Chair of Pediatrics, Department of Educational Sciences, Chair of Pediatrics, University of Catania, Catania, Italy
› Author Affiliations
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Abstract

Recent progress in developmental biology, molecular genetics, and neuroimaging has enabled a more profound comprehension of developmental disorders affecting the embryonic midbrain and hindbrain, which manifest clinically. The purpose of this review is to describe anomalies of the midbrain/hindbrain such as pontocerebellar hypoplasia (PCH), congenital disorders of glycosylation (CDG), cerebellar hemisphere hypoplasia. PCH is a group of disorders that is both clinically and genetically diverse. These disorders are identified by the hypoplasia and degeneration of the cerebellum and ventral pons. A total of 18 distinct clinical subtypes of PCH, each linked to pathogenic variants in 19 different genes, have been documented, like mutations in TSEN54 (coding a subunit of tRNA splicing endonucleases complex) and TBC1D23 which display moderate-to-severe intellectual disability (ID) and microcephaly. CDG represent a set of inherited conditions marked by impaired glycosylation of proteins and lipids. The most prevalent subtype among CDG is PMM2-CDG, inherited in a recessive manner, causing reduced activity of phosphomannomutase. Its phenotype varies from mild to severe, involving the central nervous system and affecting many other organs as well. Patients who are severely affected also exhibit visceral symptoms alongside severe ID and other neurological manifestations. Cerebellar hypoplasia (CH) is characterized by a cerebellum of diminished volume while maintaining its shape. CH exhibits a diverse range of neuroradiologic features, etiologies, clinical characteristics, and neurodevelopmental involvement. Cerebello–oculo–facio–genital syndrome is linked to a recessive MAB21L1 mutation. Jubert's syndrome, associated with a rare autosomal recessive mutation, is identified on magnetic resonance imaging by cerebellar worm hypoplasia and midbrain malformations. The rhombencephalosynapsis, characterized by vermian agenesis or hypogenesis with the fusion of the cerebellar hemispheres, emerges during embryogenesis. It can manifest alone or in conjunction with other and/or extracerebral abnormalities.



Publication History

Received: 18 December 2023

Accepted: 03 April 2024

Article published online:
29 May 2024

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