RESUMO
OBJECTIVE: The present study is aimed at performing the molecular characterization of a Tunisian family with piebaldism. METHODS: As the proband and her mother showed a severe phenotype, we first chose to screen exons 10, 11, 12, 13, 16, 17 and 18 of the KIT proto-oncogene by direct sequencing. RESULTS: Direct sequencing analysis showed a C to T substitution at 1939 in exon 13 (c.1939C>T) in heterozygous state in the patient and her mother. The mutation was not found in their unaffected family members or normal controls. CONCLUSION: Our results provide additional support that mutations in the tyrosine kinase domain of the KIT gene are responsible for the severe form of piebaldism.
Assuntos
Mutação de Sentido Incorreto , Piebaldismo/genética , Mutação Puntual , Proteínas Proto-Oncogênicas c-kit/genética , Substituição de Aminoácidos , Domínio Catalítico , Éxons/genética , Feminino , Humanos , Lactente , Masculino , Fenótipo , Estrutura Terciária de Proteína , Proto-Oncogene Mas , Análise de Sequência de DNA , TunísiaRESUMO
Sanjad-Sakati syndrome (SSS) (OMIM 241410) is a rare autosomal recessive disorder characterized by congenital hypoparathyroidism with growth and mental retardation associated with seizures and a characteristic physiognomy. SSS molecular pathology has been shown to be due to mutations in the TBCE gene on chromosome 1q42-q43. All affected patients of Arab origin are homozygous for a 12-bp (155-166del) deletion in exon 3 of this gene. We report on a Tunisian child with SSS who was homozygous for the 155-166del mutation. Our findings provide additional support of the common (155-166del) deletion founder effect in exon 3 of the TBCE gene in Arab patients. It is very likely that this mutation originated in the Middle East and was introduced in Tunisia by the Banu Hilal invaders.