We report a case of Angelman syndrome (AS) with paternal uniparental
disomy (pUPD) of chromosome 15. This 6-year-old girl with overgrowth had
frequent, but only provoked laughter, was mildly ataxic with limb
hypertonia, and had no intelligible speech. She had deep-set eyes,
protruding tongue, and prominent chin. The karyotype was normal. DNA
analysis with microsatellites from chromosome 15 showed no inheritance
of maternal alleles both within and outside the AS critical region.
Proximal markers showed reduction to homozygosity of paternal alleles,
intermediate markers showed nonreduction, and distal markers reduction,
thus suggesting a meiosis II nondisjunction event in the father with two
crossovers. This is, to our knowledge, the first reported case of AS due
to meiosis II nondisjunction. We present detailed physical measurements
in this patient, adding to the clinical description of the milder
phenotype in AS due to pUPD