Background: Noonan syndrome is an autosomal dominant syndrome that is characterized by specific features including congenital heart defect, namely pulmonary stenosis, thorax deformity, short stature, and skin manifestations. Moreover, the syndrome is characterized by dysmorphic facial features of low-set ears, hypertelorism, ptosis, and downward slanting palpebral fissures. Noonan syndrome is associated with RASopathies, a group of overlapping genotype-phenotype-related syndromes. Eleven genes have been found to be causing Noonan syndrome, including PTPN11, SOS1, CBL, BRAF, RAF1, SHOC2, MAP2K1, RIT1, NRAS, KRAS, and RRAS. It has been reported that NRAS mutation was detected in Noonan syndrome which is very limited and estimated to be only 2% of all Noonan syndrome cases.
Case Presentation: In this paper, we report a rare case of mutation of the NRAS gene causing Noonan syndrome type 6 in a 10-year-old Saudi child. The patient in his early infancy had early motor delay. Moreover, he had some of the characteristics of the disease, namely the dysmorphic features, including low-set ears, hypertelorism, short neck, downward slanting palpebral fissures, and wide-spaced nipples. He has left eye ptosis and refractory errors. In addition, the echocardiogram showed pulmonary stenosis.
Conclusion: Noonan syndrome is a clinically and genetically heterogenous autosomal dominant disorder. The classical clinical features used to diagnose it include short stature and congenital heart disease. However, it can affect all body systems. Thus, achieving an accurate diagnosis is crucial.
Key words: RASopathies, Noonan syndrome, NRAS, Autosomal dominant, Saudi Arabia
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