I dont think that surname being from portuguese roots,
Probably it was writen the way they pronouced it.
Yet, I cant think of a name with that sound
Karlushko - Itajai/SC/Brasil - New York/USA
Pesquisando:
Alemanha, Belgica, Brasil, Luxemburgo, Italia, Portugal, Açores, Espanha
Agueda, Aguiar, André, Antunes, Arruda, Baptista, Beirao, Brasil, Bulcão, Cardoso, Correia, Costa, Dias, Dutra, Faria, Fernandes, Ferreira, Figueiro, Gaspar, Gato, Gomes Gonçalves, Guedes, Jorge, Leal, Lemos, Macedo, Machado, Marques, Martins, Matos, Mello, Miranda, Moreira, Nascimento, Netto, Nogueira, Nunes, Oliveira, Pereira, Ponte, Quadrado, Rebello, Rodrigues,
Santos, Silva, Silveira, Simão, Sodré, Souza, Vieira, Zabuya, Fiorenzano, Bertemes, Reinert, Ottekier, Van der Gocht, de Pres, Hesse, Laux, Schumer, Jungklaus.