A ternary complex comprised of SHOC2, MRAS, and PP1 (SHOC2 complex) functions as a RAF S259 holophosphatase and gain-of-function mutations in SHOC2, MRAS, and PP1 that promote complex formation are found in Noonan syndrome.
Recently, six patients with craniosynostosis and Noonan syndrome involving KRAS mutations were described in a review, and a patient with craniosynostosis and Noonan syndrome involving a SHOC2 mutation has also been reported.
We reported for the first time a case of 13-year-old boy with NS with loose anagen hair (NSLAH) resulting from mutation in SHOC2 who developed an autoimmune disorder that fulfilled four American College of Rheumatology (ACR) criteria for the classification of SLE (polyarthritis, pericarditis, antinuclear antibodies, and anti-DNA antibodies).
SHOC2 is mutated in Noonan syndrome and plays a key role in the activation of the ERK-MAPK pathway, which is upregulated in the majority of human cancers.
Severe craniosynostosis with Noonan syndrome phenotype associated with SHOC2 mutation: clinical evidence of crosslink between FGFR and RAS signaling pathways.
PTPN11 (39.0%), SOS1 (20.3%), RAF1 (6.8%), KRAS (5.1%), and BRAF (1.7%) mutations were identified in NS; BRAF (41.2%), SHOC2 (23.5%), and MEK1 (5.9%) mutations in cardiofaciocutaneous syndrome; and HRAS and PTPN11 mutations in Costello syndrome and LEOPARD syndrome, respectively.
Clinical testing of genes causative of Noonan syndrome and related disorders detected the previously reported, pathogenic, de novo SHOC2 missense mutation predicting p.Ser2Gly.
Activating mutations in MRAS (as well as SHOC2 and PP1) do occur in the RASopathy Noonan syndrome, underscoring a key role for MRAS within the RAS-ERK pathway.
Germline mutations in genes encoding small GTPases of the RAS family (KRAS and NRAS), modulators of RAS function (PTPN11, SOS1 and SHOC2) or downstream signal transducers (RAF1) are causative for NS.
Gene expression profiling was also resolved in five subjects with Noonan-like syndrome with loose anagen hair (NS/LAH), a condition clinically related to NS and caused by an invariant mutation in SHOC2.
Gene-related Chinese NS facial features were described using artificial intelligence (AI).NGS identified pathogenic variants in 103 Chinese patients in eight NS-related genes: PTPN11 (48.5%), SOS1 (12.6%), SHOC2 (11.7%), KRAS (9.71%), RAF1 (7.77%), RIT1 (6.8%), CBL (0.97%), NRAS (0.97%), and LZTR1 (0.97%).
In order to understand the contribution of SHOC2 mutations to the clinical manifestations of Noonan syndrome and related disorders, we analyzed SHOC2 in 92 patients with Noonan syndrome and related disorders who did not exhibit PTPN11, KRAS, HRAS, BRAF, MAP2K1/2, SOS1 or RAF1 mutations.
Noonan-like syndrome with loose anagen hair (NS/LAH; OMIM 607721), recently related to the invariant c.4A>G missense change in SHOC2, is characterized by features reminiscent of Noonan syndrome.
A recurrent activating mutation in SHOC2 (p.Ser2Gly) causes Mazzanti syndrome, a RASopathy characterized by features resembling Noonan syndrome and distinctive ectodermal abnormalities.
In order to understand the contribution of SHOC2 mutations to the clinical manifestations of Noonan syndrome and related disorders, we analyzed SHOC2 in 92 patients with Noonan syndrome and related disorders who did not exhibit PTPN11, KRAS, HRAS, BRAF, MAP2K1/2, SOS1 or RAF1 mutations.
Clinical testing of genes causative of Noonan syndrome and related disorders detected the previously reported, pathogenic, de novo SHOC2 missense mutation predicting p.Ser2Gly.