You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Variant", "Disease", "Species", "CellLine", "Chemical", "Gene"].

Please return the output as a JSON object of the format: {"CellLine": ["hRPTEC", ...], "Chemical": ["Glucose", ...], "Disease": ["Diabetes", ...], "Gene": ["HNF-6", ...], "Species": ["Patients", ...], "Variant": ["Pro75Ala", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Two distinct mutations at a single BamHI site in phenylketonuria. Classical phenylketonuria is an autosomal recessive disease caused by a deficiency of hepatic phenylalanine hydroxylase (PAH). The abolition of an invariant BamHI site located in the coding sequence of the PAH gene (exon 7) led to the recognition of two new point mutations at codon 272 and 273 (272gly----stop and 273ser----phe, respectively). Both mutations were detected in north eastern France or Belgium and occurred on the background of RFLP haplotype 7 alleles. The present study supports the view that the clinical heterogeneity in PKU is accounted for by the large variety of mutant genotypes associated with PAH deficiencies..
{"CellLine": [], "Chemical": [], "Disease": ["PAH deficiencies", "deficiency of hepatic phenylalanine hydroxylase", "Classical phenylketonuria", "phenylketonuria", "autosomal recessive disease", "PKU"], "Gene": ["PAH"], "Species": [], "Variant": ["272gly----stop", "273ser----phe"]}