[P2-33] A Case of FOXP1 abnormal mutation with white matter abnormalities
【Introduction】 The FOXP1 (forkhead box P1), located in 3p13 is detected mostly in striatum, cortex and the hippocampus. The FOXP1 mutation can cause intellectual disability, speech retardation, spasticity, and hypotonia, however, there has been no report of brain MRI in a patient with FOXP1 mutation. 【Case Report】 A 3 year-old boy was delivered at 38 weeks (2,650g) with no difficulties. He showed mild motor delay, i.e., head control at 3 months, crawling at 1 year, and walking without support at 1 year and 7 months, and speaking no meaningful word at present. He presented with mild macrocephaly, orbital hypertelorism, right-front cephalic prominence, bilateral cryptorchidism, left hip joint internal rotation and severe intellectual impairment. An autistic tendency has also been pointed out. MRI showed multiple T2 prolongation in the deep and subcortical white matter. G-Banding, CMV in umbilical cord, array CGH and analysis of NSD1 gene showed no abnormality. The whole exome sequence, however, revealed de novo splicing mutation (c .975-2A＞C) of FOXP1. 【Discussion】 The FOXP1 mutation is expected to cause exon 13 skipping, and his clinical features are compatible with those in previously reported. It is, therefore, reasonably considered that his clinical manifestations result from the FOXP1 mutation. MRI showed multiple white matter lesions, similar to those observed in patients with congenital CMV infection. It is suggested that the FOXP1 mutation should be considered as a differential diagnosis of leukoencephalopathy with multifocal lesions, including congenital CMV infection, CADASIL, Fabry disease, etc.