MGI Get Phenotypes

Get phenotype annotations for a mouse gene from MGI (Mouse Genome Informatics). Returns Mammalian Phenotype (MP) ontology annotations including phenotype statements derived from mutant allele studies. Uses Alliance of Genome Resources API which integrates MGI phenotype curation data. Useful for understanding mouse gene function through loss-of-function and gain-of-function phenotypes. Example: 'MGI:98834' returns Trp53 phenotypes including tumor susceptibility, apoptosis defects, etc.