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Galli J, Loi E, Strobio C, Micheletti S, Martelli P, Merabet LB, Pasini N, Semeraro F, Fazzi E. Neurovisual profile in children affected by Angelman syndrome. Brain Dev 2023; 45:117-125. [PMID: 36344336 DOI: 10.1016/j.braindev.2022.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/09/2022] [Accepted: 10/08/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND Angelman syndrome (AS) is a rare neurogenetic disorder caused by altered expression of the maternal copy of the UBE3A gene. Together with motor, cognitive, and speech impairment, ophthalmological findings including strabismus, and ocular fundus hypopigmentation characterize the clinical phenotype. The aim of this study was to detail the neurovisual profile of children affected by AS and to explore any possible genotype-phenotype correlations. METHODS Thirty-seven children (23 females, mean age 102.8 ± 54.4 months, age range 22 to 251 months) with molecular confirmed diagnosis of AS were enrolled in the study. All underwent a comprehensive video-recorded neurovisual evaluation including the assessment of ophthalmological aspects, oculomotor functions, and basic visual abilities. RESULTS All children had visual impairments mainly characterized by refractive errors, ocular fundus changes, strabismus, discontinuous/jerky smooth pursuit and altered saccadic movements, and/or reduced visual acuity. Comparing the neurovisual profiles between the deletion and non-deletion genetic subgroups, we found a significant statistical correlation between genotype and ocular fundus hypopigmentation (p = 0.03), discontinuous smooth pursuit (p < 0.05), and contrast sensitivity abnormalities (p < 0.01) being more frequent in the deletion subgroup. CONCLUSIONS Subjects affected by AS present a wide spectrum of neurovisual impairments that lead to a clinical profile consistent with cerebral visual impairment (CVI). Moreover, subjects with a chromosome deletion show a more severe visual phenotype with respect to ocular fundus changes, smooth pursuit movements, and contrast sensitivity. Early detection of these impaired visual functions may help promote the introduction of neurovisual habilitative programs which can improve children's visual, neuromotor, and cognitive outcomes.
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Affiliation(s)
- Jessica Galli
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy; Unit of Child Neurology and Psychiatry, ASST Spedali Civili of Brescia, Brescia, Italy.
| | - Erika Loi
- Unit of Child Neurology and Psychiatry, ASST Spedali Civili of Brescia, Brescia, Italy; Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Caterina Strobio
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Serena Micheletti
- Unit of Child Neurology and Psychiatry, ASST Spedali Civili of Brescia, Brescia, Italy
| | - Paola Martelli
- Unit of Child Neurology and Psychiatry, ASST Spedali Civili of Brescia, Brescia, Italy
| | - Lotfi B Merabet
- The Laboratory for Visual Neuroplasticity, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Nadia Pasini
- Department of Neurological and Vision Sciences, ASST Spedali Civili of Brescia, Italy
| | - Francesco Semeraro
- Department of Neurological and Vision Sciences, ASST Spedali Civili of Brescia, Italy; University of Brescia, Eye Clinic, Brescia, Italy
| | - Elisa Fazzi
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy; Unit of Child Neurology and Psychiatry, ASST Spedali Civili of Brescia, Brescia, Italy
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Michieletto P, Bonanni P, Pensiero S. Ophthalmic findings in Angelman syndrome. J AAPOS 2011; 15:158-61. [PMID: 21596294 DOI: 10.1016/j.jaapos.2010.12.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 12/03/2010] [Accepted: 12/06/2010] [Indexed: 01/16/2023]
Abstract
PURPOSE To provide detailed information about opthalmological findings in a group of patients with Angelman syndrome (AS). METHODS Consecutive patients with a genetically confirmed diagnosis of AS were submitted to ophthalmic and orthoptic examinations. Strabismus, visual acuity, cycloplegic refraction, and iris and fundus pigmentation were evaluated. Parents were also examined to compare the extent of fundus pigmentation. RESULTS A total of 34 patients were identified, representing 3 genetic classes: deletion, uniparental disomy, and mutation. Ametropia >1 D was present in 97% of cases: myopia in 9%, hyperopia in 76%, and astigmatism in 94%. Myopia and anisometropia were found only in the genetic deletion group. Strabismus, most frequently exotropia, was found in 24 patients (75%). Ocular hypopigmentation was observed in 18 subjects (53%), with choroidal involvement in 3 cases and isolated iris involvement in 4. Hypopigmentation was observed in all of the 3 genetic classes. CONCLUSIONS Ophthalmic alterations in AS were observed more frequently than has been previously reported, except for ocular hypopigmentation, which was observed less frequently.
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Affiliation(s)
- Paola Michieletto
- IRCCS Eugenio Medea, polo di Conegliano e Pieve di Soligo (TV), Italy
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Horsler K, Oliver C. The behavioural phenotype of Angelman syndrome. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2006; 50:33-53. [PMID: 16316429 DOI: 10.1111/j.1365-2788.2005.00730.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
BACKGROUND The purpose of this review is to examine the notion of a behavioural phenotype for Angelman syndrome and identify methodological and conceptual influences on the accepted presentation. METHODS Studies examining the behavioural characteristics associated with Angelman syndrome are reviewed and methodology is described. RESULTS Potential bias in the description of the phenotype emerges with the use of case and cohort studies with the absence of comparison groups. A trend in the literature from a direct gene effect to a socially mediated effect on laughter is evident. CONCLUSION Evidence for a behavioural phenotype of Angelman syndrome has begun to emerge. However, by adopting the concept of a 'behavioural phenotype', attention may become biased towards the underlying biological basis of the syndrome, with developmental and environmental factors being overlooked.
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Affiliation(s)
- K Horsler
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, UK
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Saitoh S, Wada T, Okajima M, Takano K, Sudo A, Niikawa N. Uniparental disomy and imprinting defects in Japanese patients with Angelman syndrome. Brain Dev 2005; 27:389-91. [PMID: 16023557 DOI: 10.1016/j.braindev.2003.12.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Revised: 11/24/2003] [Accepted: 12/16/2003] [Indexed: 10/25/2022]
Abstract
We examined 54 patients with deletion-negative Angelman syndrome (AS) using DNA methylation testing and microsatellite polymorphism analysis, and identified three patients with paternal uniparental disomy (UPD) and seven patients with imprinting defects (ID). The three patients with UPD were shown to have paternal isodisomy 15, which we hypothesized to have arisen from duplication of chromosome 15. Two of the patients with ID were siblings and carried microdeletions of the imprinting center (IC), while the remaining five patients had no evidence of deletions and represented sporadic cases. Two of the three patients with UPD and two of the seven patients with ID had not developed seizures. The only patients displaying microcephaly were those with ID who had microdeletions at the IC. These data support the previous findings that indicate that patients with UPD and ID may have a milder phenotype of AS.
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Affiliation(s)
- Shinji Saitoh
- Department of Pediatrics, Graduate School of Medicine, Hokkaido University, N-15, W-7, Sapporo 060-8638, Japan.
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Abstract
Angelman syndrome (AS) is a neurodevelopmental disorder characterised by severe learning difficulties, ataxia, a seizure disorder with a characteristic EEG, subtle dysmorphic facial features, and a happy, sociable disposition. Most children present with delay in developmental milestones and slowing of head growth during the first year of life. In the majority of cases speech does not develop. Patients with AS have a characteristic behavioural phenotype with jerky movements, frequent and sometimes inappropriate laughter, a love of water, and sleep disorder. The facial features are subtle and include a wide, smiling mouth, prominent chin, and deep set eyes. It is caused by a variety of genetic abnormalities involving the chromosome 15q11-13 region, which is subject to genomic imprinting. These include maternal deletion, paternal uniparental disomy, imprinting defects, and point mutations or small deletions within the UBE3A gene, which lies within this region. UBE3A shows tissue specific imprinting, being expressed exclusively from the maternal allele in brain. The genetic mechanisms identified so far in AS are found in 85-90% of those with the clinical phenotype and all interfere with UBE3A expression.
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Affiliation(s)
- J Clayton-Smith
- Academic Department of Medical Genetics, St Mary's Hospital, Manchester, UK.
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Lossie AC, Whitney MM, Amidon D, Dong HJ, Chen P, Theriaque D, Hutson A, Nicholls RD, Zori RT, Williams CA, Driscoll DJ. Distinct phenotypes distinguish the molecular classes of Angelman syndrome. J Med Genet 2001; 38:834-45. [PMID: 11748306 PMCID: PMC1734773 DOI: 10.1136/jmg.38.12.834] [Citation(s) in RCA: 237] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Angelman syndrome (AS) is a severe neurobehavioural disorder caused by defects in the maternally derived imprinted domain located on 15q11-q13. Most patients acquire AS by one of five mechanisms: (1) a large interstitial deletion of 15q11-q13; (2) paternal uniparental disomy (UPD) of chromosome 15; (3) an imprinting defect (ID); (4) a mutation in the E3 ubiquitin protein ligase gene (UBE3A); or (5) unidentified mechanism(s). All classical patients from these classes exhibit four cardinal features, including severe developmental delay and/or mental retardation, profound speech impairment, a movement and balance disorder, and AS specific behaviour typified by an easily excitable personality with an inappropriately happy affect. In addition, patients can display other characteristics, including microcephaly, hypopigmentation, and seizures. METHODS We restricted the present study to 104 patients (93 families) with a classical AS phenotype. All of our patients were evaluated for 22 clinical variables including growth parameters, acquisition of motor skills, and history of seizures. In addition, molecular and cytogenetic analyses were used to assign a molecular class (I-V) to each patient for genotype-phenotype correlations. RESULTS In our patient repository, 22% of our families had normal DNA methylation analyses along 15q11-q13. Of these, 44% of sporadic patients had mutations within UBE3A, the largest percentage found to date. Our data indicate that the five molecular classes can be divided into four phenotypic groups: deletions, UPD and ID patients, UBE3A mutation patients, and subjects with unknown aetiology. Deletion patients are the most severely affected, while UPD and ID patients are the least. Differences in body mass index, head circumference, and seizure activity are the most pronounced among the classes. CONCLUSIONS Clinically, we were unable to distinguish between UPD and ID patients, suggesting that 15q11-q13 contains the only significant maternally expressed imprinted genes on chromosome 15.
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Affiliation(s)
- A C Lossie
- R C Philips Unit and Division of Genetics, Department of Pediatrics, University of Florida, Gainesville, FL 32610-0296, USA
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Meguro M, Kashiwagi A, Mitsuya K, Nakao M, Kondo I, Saitoh S, Oshimura M. A novel maternally expressed gene, ATP10C, encodes a putative aminophospholipid translocase associated with Angelman syndrome. Nat Genet 2001; 28:19-20. [PMID: 11326269 DOI: 10.1038/ng0501-19] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lack of a maternal contribution to the genome at the imprinted domain on proximal chromosome 15 causes Angelman syndrome (AS) associated with neurobehavioral anomalies that include severe mental retardation, ataxia and epilepsy. Although AS patients have infrequent mutations in the gene encoding an E6-AP ubiquitin ligase required for long-term synaptic potentiation (LTP), most cases are attributed to de novo maternal deletions of 15q11-q13. We report here that a novel maternally expressed gene, ATP10C, maps within the most common interval of deletion and that ATP10C expression is virtually absent from AS patients with imprinting mutations, as well as from patients with maternal deletions of 15q11-q13.
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Affiliation(s)
- M Meguro
- Core Research for Evolutional Science and Technology project, Department of Molecular and Cell Genetics, School of Life Sciences, Faculty of Medicine, Tottori University, Tottori, Japan
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Fridman C, Varela MC, Kok F, Diament A, Koiffmann CP. Paternal UPD15: further genetic and clinical studies in four Angelman syndrome patients. AMERICAN JOURNAL OF MEDICAL GENETICS 2000; 92:322-7. [PMID: 10861661 DOI: 10.1002/1096-8628(20000619)92:5<322::aid-ajmg6>3.0.co;2-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Among 25 patients diagnosed with Angelman syndrome, we detected 21 with deletion and 4 with paternal uniparental disomy (UPD), 2 isodisomies originating by postzygotic error, and 1 MII nondisjunction event. The diagnosis was obtained by molecular techniques, including methylation pattern analysis of exon 1 of SNRPN and microsatellite analysis of loci within and outside the 15q11-q13 region. Most manifestations present in deletion patients are those previously reported. Comparing the clinical data from our and published UPD patients with those with deletions we observed the following: the age of diagnosis is higher in UPD group (average 7 3/12 years), microcephaly is more frequent among deletion patients, UPD children start walking earlier (average age 2 9/12 years), whereas in deletion patients the average is 4 (1/2) years, epilepsy started later in UPD patients (average 5 10/12 years) than in deletion patients (average 1 11/12 years), weight above the 75th centile is reported mainly in UPD patients, complete absence of speech is more common in the deleted (88.9%) than in the UPD patients because half of the children are able to say few words. Thus, besides the abnormalities already described, the UPD patients have somewhat better verbal development, a weight above the 75th centile, and OFC in the upper normal range.
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Affiliation(s)
- C Fridman
- Department of Biology, Institute of Bioscience, University of São Paulo, Brazil.
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