Syndromal obesity due to paternal duplication 6(q24.3-q27).

The likelihood of a paternally expressing imprinted gene in chromosome region 6(q23-24) has been highlighted by cases of transient neonatal diabetes mellitus (TNDM) in which paternal uniparental disomy (UPD) for chromosome 6 or paternal duplication 6(q23-qter) was detected. We present the case of a 38-year-old man with moderate to severe intellectual delay, short stature, small hands and feet, eye abnormality, small mouth, and obesity (without hyperphagia) beginning in mid-childhood. The perinatal and neonatal histories were normal. The patient had a duplication within 6q. Fluorescence in situ hybrisation studies were performed with single and dual hybridisations using a chromosome 6 library probe, short and long arm subregional probes, 6q23-24, 6q25.3-6qter locus-specific probes, and a 6q telomere probe. The hybridisation results defined an inverted duplication of 6q24.3 to 6q27. DNA studies with microsatellite markers from 6p and 6q showed regular biparental inheritance of chromosome 6 and confirmed that the duplication was paternal in origin. Our patient appears to be the first one known to have paternal duplication of chromosome area 6(q24-q27) who did not have TNDM as an infant. He has remained nondiabetic, although obesity, without hyperphagia, has been a constant problem since its onset in mid-childhood.

Manifestations in institutionalised adults with Angelman syndrome due to deletion.

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.