Clinical features
Intellectual disability with persistence of fetal hemoglobin syndrome (also known as Dias-Logan syndrome) is characterized by developmental delay/intellectual disability, and fetal hemoglobin that remains high in childhood (whereas is normally low after birth), infantile hypotonia, and distinctive facial characteristics.
Prevalence
Intellectual disability with persistence of fetal hemoglobin syndrome is a rare condition. To date, only few patients have been identified, and it is impossible to estimate how many people have this syndrome. However, it is expected that more patients will be identified thanks to the newer genetic technologies currently available.
Inheritance
Intellectual disability with persistence of fetal hemoglobin syndrome, caused by a microdeletion or a mutation of BCL11A, is inherited in an autosomal dominant fashion: this means that the affected people have a change in one of the two copies of the gene, which is sufficient to cause the syndrome. To date all affected individuals result from a de novoBCL11A change, i.e. the change happened in them for the first time and was not inherited from either of the parents. The recurrence risk for future pregnancies is low (probably <1%), but greater than that of the general population because of the possibility of germline mosaicism in one of the parents (where some of the maternal egg or paternal sperm cells contain the genetic alteration or chromosome problem). Prenatal testing is theoretically feasible once the pathogenic variant is known.