Component of the mitochondrial small ribosomal subunit (mt-SSU), essential for mitochondrial protein synthesis (PubMed:25556185, PubMed:25838379). Mature mammalian 55S mitochondrial ribosomes consist of a small (28S) and a large (39S) subunit. The 28S small subunit contains a 12S ribosomal RNA (12S mt-rRNA) and 30 different proteins. The 39S large subunit contains a 16S rRNA (16S mt-rRNA), a copy of mitochondrial valine transfer RNA (mt-tRNA(Val)), which plays an integral structural role, and 52 different proteins (PubMed:25838379). The disease is caused by variants affecting the gene represented in this entry. Belongs to the universal ribosomal protein uS7 family.