ABSTRACT
Costello syndrome (CS) is a rare multiple congenital abnormality syndrome characterized by a typical coarse face, developmental delay, psychomotor and growth retardation, neurologic abnormalities, cardiac and cutaneous anomalies, severe feeding difficulties with postnatal growth failure, and increased risk of tumors. Since Costello first described it in 1971 and again in 1977, over 100 cases have been reported worldwide. It was recently shown that CS is a congenital condition caused by heterozygous de novo missense mutations affecting the codon for glycine 12 or 13 of the HRAS gene. We experienced three unrelated cases with coarse faces, developmental delays, short statures, macrocephaly, and redundant skin with deep palmar and plantar creases, hypertrophic cardiomyopathy and atrial tachycardia, which are characteristic of CS.