[Prenatal genetic diagnosis for a fetus with atypical neurofibromatosis type 1 microdeletion].

OBJECTIVE: To analyze the correlation between atypical neurofibromatosis type 1(NF1) microdeletion and fetal phenotype.

METHODS: Fetal blood sampling was carried out for a woman bearing a fetus with talipes equinovarus. G-banded karyotyping and single nucleotide polymorphism array (SNP-array) were performed on the fetal blood sample. Fluorescence in situ hybridization (FISH) was used to confirm the result of SNP array analysis. FISH assay was also carried out on peripheral blood specimens from the parents to ascertain the origin of mutation.

RESULTS: The karyotype of fetus was found to be 46, XY by G-banding analysis. However, a 3.132 Mb microdeletion was detected in chromosome region 17q11.2 by SNP array, which overlaped with the region of NF1 microdeletion syndrome. Analyzing of the specimens from the fetus and its parents with FISH has confirmed it to be a de novo deletion.

CONCLUSION: Talipes equinovarus may be an abnormal sonographic feature of fetus with atypical NF1 microdeletion which can be accurately diagnosed with SNP array.