Bibliographie

1. J. BRAECKEVELDT, G. POINT and G. VANDERMOT, Angelman syndrome : 23 years clinical history of first Belgian diagnosed case ;
2. F. THERASSE, Bernard DAN, P. HILBERT and L. VAN MALDERGEM, Institutionalized adults with Angelman syndrome.

Undiagnosed institutionalised patients were reviewed in an attempt to identify those with Angelman syndrome (AS). The aim was to test these patients for deletion of chromosome 15(q11-13) and to describe the adult phenotype. The selection criteria included severe intellectual disability, ataxic or hypermotoric limb movements, lack of speech, a "happy" demeanour, epilepsy, and facial appearance consistent with the diagnosis. Patients were examined, medical records perused, and patients' doctors contacted as required. Genetic tests performed included routine cytogenetics, DNA methylation analysis (with probe PW71B), and fluorescence in situ hybridisation (with probes D15S10, GABRbeta3, or SNRPN). A deletion in the AS region was detected in 11 patients (9 males and 2 females) of 22 tested. The mean age at last review (March 1996) was 31.5 years (range 24 to 36 years). Clinical assessment documented findings of large mouth and jaw with deep set eyes, and microcephaly in nine patients (two having a large head size for height). No patient was hypopigmented; 1/11 patients was fair. Outbursts of laughter occurred in all patients but infrequently in 7/11 (64%) and a constant happy demeanour was present in 5/11 (46%). All had epilepsy, with improvement in 5/11 (46%), no change in 4 (36%), and deterioration in 2 (18%). The EEG was abnormal in 10/10 patients. Ocular abnormalities were reported in 3/8 patients (37.5%) and 4/11 (36%) had developed kyphosis. Two had never walked. All nine who walked were ataxic with an awkward, clumsy, heavy, and/or lilting gait. No patient had a single word of speech but one patient could use sign language for two needs (food and drink). Our data support the concept that AS resulting from deletion is a severe neurological syndrome in adulthood. The diagnosis in adults may not be straightforward as some manifestations change with age. Kyphosis and keratoconus are two problems of older patients.

We studied the clinical and EEG-findings in 28 adult patients (aged 20-53 years) with Angelman syndrome (AS). Twenty-three showed a maternal chromosome 15q11-13 deletion; in 5, the diagnosis was based on a combination of typical clinical findings. Compared to the clinical manifestations present in childhood, "coarsening" of facial traits (100%), thoracic scoliosis (71%), and being wheelchair-bound (39%) were found more frequently. Paroxysms of laughter were still observed in adulthood (79%), but less frequently than in childhood. Most adult patients could feed themselves, but needed help with many daily activities. The majority (82%) had epileptic seizures. Abnormal EEG-activity consisting of 2-3/s rhythmic triphasic waves of high amplitude with a maximum over the frontal regions, which has been identified in many AS children, was found in 67% of these adult patients.