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Physical examination and investigations
Published in Ajay Sharma, Helen Cockerill, From Birth to Five Years, 2021
For behaviour suggestive of seizures, the behavioural phenotype of Angelman syndrome consider: Electroencephalogram (EEG).
Adenylosuccinate lyase deficiency
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
A behavioral phenotype has been reported [20] resembling Angelman syndrome. Two sisters, 11 and 12 years of age, had global developmental delay, motor apraxia, and severe deficits in speech. They also had seizures. The behavior was characterized by happy dispositions and excessive laughter. They were hyperactive and had short attention spans. They mouthed objects and had tantrums and stereotypical movements. Self-injurious behavior has been observed in this disease [1, 3, 21].
Chromosome abnormalities
Published in Angus Clarke, Alex Murray, Julian Sampson, Harper's Practical Genetic Counselling, 2019
Now that responsible genes have been identified in the critical region of chromosome 15, it is usually possible to determine the genetic basis of Prader-Willi syndrome or of Angelman syndrome. The causes of Angelman syndrome are more complex and varied: mutation in the maternally inherited UBE3A gene will lead to Angelman syndrome, just as with a deletion of the maternal 15q, paternal disomy 15 or a disturbance of the local imprinting mechanism.
Septo-optic dysplasia presenting with nystagmus, pseudo-disc edema, and fovea hypoplasia
Published in Ophthalmic Genetics, 2022
Richard Sather ΙΙΙ, Dorothy Thompson, Jacqueline Ihinger, Sandra R. Montezuma
In parallel, the child had a 293 gene panel for genes associated with inherited retinal disorders and nystagmus (Invitae Laboratory). This testing identified one pathogenic variant and one variant of uncertain significance in the SLC45A2. The SCL45A2 gene is associated with autosomal recessive oculocutaneous albinism type 4 (OCA4). The c.987del (p.Ala330Profs*68) pathogenic variant and the c.987C>G (p.Thr329Arg) variant of uncertain significance were confirmed to be on the same chromosome (in cis). Therefore, this individual is a carrier for autosomal recessive SLC45A2-related conditions. Additionally, the patient did have sequencing and deletion/duplication analysis of the OCA2 gene included on his IRD panel and no variants in OCA2 were identified. Testing for Angelman syndrome and Prader–Willi syndrome was not performed as there was no clinical suspicion for these conditions at the time of evaluation. It should be further addressed that the patient can verbalize and carry out a conversation. This would also contribute against the suspicion for Angelman syndrome.
Therapeutic approach to neurological manifestations of Angelman syndrome
Published in Expert Review of Clinical Pharmacology, 2022
Michele Ascoli, Maurizio Elia, Sara Gasparini, Paolo Bonanni, Giovanni Mastroianni, Vittoria Cianci, Sabrina Neri, Angelo Pascarella, Domenico Santangelo, Umberto Aguglia, Edoardo Ferlazzo
Angelman syndrome (AS) is a neurogenetic disorder with an estimated prevalence between 1/12,000 and 1/20,000; the incidence is unknown [1–3]. Angelman syndrome is caused by deficient expression of the maternal copy of the ubiquitin protein ligase E3A, which is responsible for the ubiquitination of macromolecules destined for degradation. E3A is encoded by the UBE3A gene located on chromosome 15q11-q13. Angelman syndrome may be due to one of four molecular etiologies: deletion, paternal uniparental disomy, imprinting defect and mutations in the maternally inherited copy of UBE3A [4]. Angelman syndrome is clinically characterized by microcephaly, facial dysmorphisms, severe intellectual disability, absent speech, epilepsy, myoclonus, dystonia, gait disturbance and a typical behavioral profile that includes a joyful attitude, low attention span and hyperactivity. Clinical variability exists among the different genetic subgroups as patients with the deletion of maternal copy of 15q11.2–13 region usually show the most severe phenotype [4,5].
Therapies in preclinical and clinical development for Angelman syndrome
Published in Expert Opinion on Investigational Drugs, 2021
Theodora Markati, Jessica Duis, Laurent Servais
Angelman syndrome (AS), first characterized by Dr Harry Angelman in 1965, is a rare genetic neurodevelopmental disorder diagnosed in one in 12,000–20,000 live births (NORD, 2018 & OMIM 105830). AS patients present with global developmental delay, learning difficulties, and particularly severe expressive language delay. Behaviorally, patients have a characteristically happy demeanor, which is usually expressed as unprovoked laughter, a love for water, and maladaptive behavior. Patients have movement disorders, including gait ataxia, tremulousness of the limbs, and generalized hypotonia of the trunk. Commonly, patients also have seizure activity and sleep disturbance [1–8]. Treatment is supportive with a focus on seizures, sleep, and behavior, as no disease-modifying or AS-specific treatments are currently available.