Publicação

An explanation for another familial case of Rett syndrome: maternal germline mosaicism

Detalhes bibliográficos
Resumo:	Rett syndrome (RTT; OMIM#312750) is a severe neurodevelopmental disorder that affects mainly girls. It has an estimated incidence of 1:10,000-15,000 females. Mutations in the X-linked gene methyl CpG-binding protein 2 (MECP2) have been found in most patients. The most accepted explanation for the sex bias is that the Rett mutation in sporadic cases has its origin in the paternal germline X chromosome and can thus only be transmitted to females. The majority of cases are sporadic (99.5%) but some familial cases have been described. These cases can either be explained by germline mosaicism or by asymptomatic carrier mothers with skewing of X-inactivation towards the wild-type MECP2 allele. We describe one of the few familial cases of RTT in which a maternal germline mosaicism is the most likely explanation. The mutation p.Arg270fs (c.808delC) was identified in both a girl with classical RTT and her brother who had the severe neurological phenotype usually described in males. The mutation was absent in DNA extracted from blood of both parents. These type of events must be taken into consideration in the genetic counselling of families after the diagnosis of a first case of RTT in a female or a MECP2 mutation in a male.
Autores principais:	Venâncio, Margarida
Outros Autores:	Santos, Mónica; Pereira, Susana Aires; Maciel, P.; Saraiva, Jorge M.
Assunto:	Child, Preschool Female Humans Infant Male Methyl-CpG-Binding Protein 2 Rett Syndrome Mosaicism Mothers Maternal germline mosaicism MECP2
Ano:	2007
País:	Portugal
Tipo de documento:	artigo
Tipo de acesso:	acesso aberto
Instituição associada:	Universidade do Minho
Idioma:	inglês
Origem:	RepositóriUM - Universidade do Minho

Descrição
Resumo:	Rett syndrome (RTT; OMIM#312750) is a severe neurodevelopmental disorder that affects mainly girls. It has an estimated incidence of 1:10,000-15,000 females. Mutations in the X-linked gene methyl CpG-binding protein 2 (MECP2) have been found in most patients. The most accepted explanation for the sex bias is that the Rett mutation in sporadic cases has its origin in the paternal germline X chromosome and can thus only be transmitted to females. The majority of cases are sporadic (99.5%) but some familial cases have been described. These cases can either be explained by germline mosaicism or by asymptomatic carrier mothers with skewing of X-inactivation towards the wild-type MECP2 allele. We describe one of the few familial cases of RTT in which a maternal germline mosaicism is the most likely explanation. The mutation p.Arg270fs (c.808delC) was identified in both a girl with classical RTT and her brother who had the severe neurological phenotype usually described in males. The mutation was absent in DNA extracted from blood of both parents. These type of events must be taken into consideration in the genetic counselling of families after the diagnosis of a first case of RTT in a female or a MECP2 mutation in a male.