A rare syndrome including neonatal and infantile hypotonia and failure to thrive, cystinuria type 1 and nephrolithiasis, growth retardation due to growth hormone deficiency, and minor facial dysmorphism. The disease is Monarch Disease Ontology term MONDO_0011669 (hypotonia-cystinuria syndrome). Also known as: HCS, cystinuria with mitochondrial disease, hypotonia-cystinuria syndrome type 1, hypotonia-cystinuria type 1 syndrome.