Best Answer: Chordata refers to the presence of a nerve chord running from the head to the back, which may or may not be accompanied by vertebrae. All animals with backbones are members of the chordate phylum, but not all chordates have bones (lancelets and tunicates are chordates lacking real bones).
Angelman syndrome (AS) is a genetic disorder that causes developmental delay, intellectual disability, speech problems, seizures (epilepsy), and problems with movement and balance (ataxia).ngelman syndrome (AS) is a severe neurodevelopmental disorder caused by maternal deficiency of the imprinted gene UBE3A. Individuals with AS suffer from intellectual disability, speech impairment, and motor dysfunction. Currently there is no cure for the disease.
The most common cause of Angelman syndrome is a deletion of the maternal chromosome region 15q11-q13, which includes the UBE3A gene. Importantly, mutations and deletions of the UBE3A gene are sufficient to cause Angelman syndrome, making UBE3A the single gene responsible for the core symptoms of the disorder. Two major deletion classes known as class I and class II deletions in the 15q11-q13 region both cause Angelman syndrome.