Paternal transmission of a FMR1 full mutation allele

We present a 16‐year‐old girl with a mild fragile X syndrome phenotype. FMR1 gene study showed that the patient inherited a mosaic premutation‐full mutation with an unmethylated uninterrupted allele (175, >200 CGG) from her father. The father showed an 88 CGG uninterrupted unmethylated allele in blood and sperm cells. To our knowledge, this is the first case of a FMR1 mosaic premutation‐full mutation allele inherited from a PM father. In our opinion, the most likely explanation could be a postzygotic somatic expansion. We can conclude that in rare cases of a child with a full mutation whose mother does not carry a premutation, the possibility of paternal transmission should be considered.

Source: American Journal of Medical Genetics Part A - August 16, 2017 Category: Genetics & Stem Cells Authors: Maria Isabel Alvarez ‐Mora, Miriam Guitart, Laia Rodriguez‐Revenga, Irene Madrigal, Elisabeth Gabau, Montserrat Milà Tags: CLINICAL REPORT Source Type: research