Premium
Two novel germline KRAS mutations: expanding the molecular and clinical phenotype
Author(s) -
Stark Z,
GillessenKaesbach G,
Ryan MM,
Cirstea IC,
Gremer L,
Ahmadian MR,
Savarirayan R,
Zenker M
Publication year - 2012
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/j.1399-0004.2011.01754.x
Subject(s) - kras , noonan syndrome , missense mutation , genetics , germline mutation , mutation , phenotype , germline , biology , cancer research , medicine , gene
Stark Z, Gillessen‐Kaesbach G, Ryan MM, Cirstea IC, Gremer L, Ahmadian MR, Savarirayan R, Zenker M. Two novel germline KRAS mutations: expanding the molecular and clinical phenotype. Noonan and Cardio‐facio‐cutaneous (CFC) syndromes are characterized by typical dysmorphic features, cardiac defects, short stature, variable ectodermal anomalies, and intellectual disability. Both belong to the Ras/mitogen‐activated protein kinase pathway group of disorders and clinical features overlap other related conditions, notably LEOPARD and Costello syndromes. KRAS mutations account for about 2% of reported Noonan and <5% of reported CFC cases. The mutation spectrum includes recurrent missense changes clustering in particular domains of the KRAS protein and conferring gain‐of‐function. We report three patients from two unrelated families with novel missense KRAS mutations, p.K147E and p.Y71H. Both mutations affect a residue which is highly conserved in KRAS and other RAS isoforms. One of the families includes a mother and son pair who represent the first report of a vertically transmitted KRAS mutation. In addition, the mother and son pair had peripheral neuropathy, complicated by Charcot arthropathy in the mother. An unusual phenotypic effect of the specific KRAS mutation or a coincidence of two independent disorders may be considered. KRAS mutation‐associated phenotypes appear to be subject to considerable clinical heterogeneity. All three cases highlight the challenges of clinical assessment in KRAS mutation‐positive patients, and the utility of molecular testing as an adjunct to diagnosis.