Diagnosis of PWS and AS in neonates often involves a combination of clinical evaluation and genetic testing. Clinical signs such as hypotonia, feeding difficulties, and developmental delays may prompt genetic testing. The most common diagnostic tests include: 1. Methylation analysis, which can detect most cases of PWS and AS by identifying abnormalities in the imprinting pattern. 2. FISH (Fluorescence In Situ Hybridization) or MLPA (Multiplex Ligation-dependent Probe Amplification) to detect deletions in chromosome 15. 3. SNP array or karyotyping to detect uniparental disomy. 4. Sequencing of the UBE3A gene in suspected AS cases where deletions or UPD are not found.
