Hypotonia-cystinuria type 1

**Definition:** This is a rare syndrome including neonatal and infantile hypotonia and failure to thrive, cystinuria type 1, nephrolithiasis, growth retardation due to growth hormone deficiency, and minor facial dysmorphism due to a homozygous deletion of two contiguous genes on chromosome 2: SLC3A1 and PREP (2p21).