Clinical-Neurological, cytogenetic and molecular aspects of Prader-Willi and Angelman syndromes

The Prader-Willi syndrome (PWS) and the Angelman syndrome (AS) are human neurogenetic disorders involving the imprinting mechanism, at the 15q11-13 chromosome region. The predominant genetic defects in PW are 15q 11-13 deletions of paternal origin and maternal chromosome 15 uniparental disomy. In contrast, maternal deletions and paternal chromosome 15 uniparental disomy are associated with a different neurogenetic disorder, the AS. In both disorders, these mutations are associated with parent-of-origin specific methylation at several 15q 11-13 loci. We studied 5 patients suspect of PWS and 4 patients suspect of AS who were referred to the Medical Genetics Unit at the University Hospital of Medical School from Ribeirão Preto. Our objective was to establish the correct clinical and etiological diagnosis in these cases. We used conventional cytogenetics, methylation analysis with the probe KB 17 (CpG island of the SNRPN gene) by Southern blotting after digestion with the Xba I and Not I restriction enzymes. We studied in patients and their parents the segregation of the (CA)n repeats polymorphisms by PCR, using the primers 196 and IR4-3R. All the patients had normal conventional cytogenetical analysis. We confirmed 3 cases of PWS: one by de novo deletion, one by maternal chromosome 15 uniparental disomy and one case with no defined cause determined by the used primers. We confirmed 2 cases of AS, caused by de novo deletion at the 15q 11-13 region, and one case with normal molecular analysis but with strong clinical characteristics

Somatic and germ cell cytogenetic studies and AZF microdeletion screening in infertile men

Clinical and cytogenetic studies were performed in 65 infertile individuals, and 56 of them were also screened for microdeletions in Yq11 (AZF region). Relevant environmental etiological factors were identified in 10 cases (15.4%). Sertoli-cell-only syndrome was diagnosed in six patients (9,2%). Karyotype abnormalities were detected in six individuals, and five other patients presented desynapsis of bivalents in meiosis. Three out of the 56 patients studied were carriers of microdeletions in the AZF region, one of them also presenting a chromosomal mosaicism for an extra i(22p).27447748

Atypical presentation of Prader-Willi syndrome with Klinefelter (XXY karytype) and craniosynostosis Síndrome de Prader-Willi em paciente com Klinefelter (cariótipo XXY) e craniossinostose

Prader-Willi syndrome is a mental retardation genetic disorder also characterized by hypogonadism, hyperphagia and obesity. We report on a four-years-old boy, born to consanguineous parents, with uncommon co-occurrence of Prader-Willi syndrome, 47,XXY karyotype (Klinefelter syndrome) and coronal craniosynostosis. These are different unrelated conditions and it was not described before in the same patient to the best of our knowledge.<br>A síndrome de Prader-Willi é afecção genética de deficiência mental associada a hipogonadismo hipogonadotrófico, hiperfagia e obesidade. Descrevemos o caso de menino de 4 anos de idade, filho de casal consangüíneo, apresentando três condições clínicas não relacionadas: síndrome de Prader-Willi, cariótipo 47,XXY (compatível com síndrome de Klinefelter) e craniossinostose coronal. Ao nosso conhecimento, não foi relatado caso semelhante previamente na literatura