Chiari 1 malformation in patient with Noonan syndrome: A case report and review of literature.

Background: Different theories exist about the pathogenesis of Chiari 1 malformations (CM-I), but none of them is thought to be exhaustive. Likewise, the role of genetic factors contributing to these conditions has not yet been elucidated, but there is a co-occurrence of CM-I with genetic syndromes such as Noonan syndrome (NS) and other RASopathies. Case Description: We describe the case of a 16-year-old female known with NS, currently presenting with Valsalva-induced headaches. Imaging of the brain and spine showed a CM-I with extensive syringohydromyelia. The patient was treated with a foramen magnum decompression and C1 laminectomy with duraplasty. The postoperative course was uneventful and the symptoms improved postoperatively. Conclusion: In the literature, sixteen cases of CM-I in patients with NS are reported. Our reported case illustrates the co-occurrence between CM-I and RASopathies. We review current literature about the understanding of the possible association or pathogenetic link between the two conditions. This case report highlights the clinical importance of recognizing the co-occurrence of CM-I and NS, potentially guiding early diagnosis and management strategies.