Table 2.

Human bone diseases associated with a failure in amino acid metabolism

Amino acid name	Genes	Disease name	Bone defects	References
Alanine	GPT	Nonalcoholic fatty liver disease	Lower bone mineral density	[40]
Proline	PYCR2		Microcephaly, facial dysmorphism, and developmental delay	[42]
Asparagine	ASNS		Epilepsy, developmental delay, and progressive microcephaly	[46]
Phenylalanine	PAH	Phenylketonuria	Osteopenia	[85–87]
Tyrosine		Dopamine-related diseases (e.g., Parkinson’s disease, Schizophrenia)	Osteoporosis	[93–95]