Abstract:

BACKGROUND: Deletion of 13q13.3 is an extremely rare event.
CASE: We report on a 25-month-old girl with neurodevelopmental disorder and intellectual disability. She had dysmorphic facies characterized by synophrys, long and narrow palpebral fissures; and a large, round face with small organs such as the eyes and mouth positioned near the center. She was hypotonic and had autism-like behaviors. Blood tests and brain MRI revealed no specific findings.
However, G-banding chromosome analysis showed an apparently balanced translocation: 46,XX,t(7,13)(q11.23;q12.3). Both parents had normal karyotypes.
Furthermore, her abnormal phenotype and chromosomal breakpoint lesion were suspected to be associated. Hence, we conducted array comparative genomic hybridization, which revealed a 3.2 Mb novel pathological microdeletion at 13q13.3 involving 17 genes including neurobeachin (NBEA), a neurodevelopment disorder gene. Furthermore, fluorescence in situ hybridization using probes adjacent to the microdeletion suggested a concomitant occurrence of the deletion and translocation as the structural basis of this rare genomic variant.
CONCLUSION: NBEA may have roles in her neurodevelopmental phenotypes, whereas other genes within the 13q13.3 microdeletion may contribute to her dysmorphic features.

日本語要旨:

NCNP病院小児神経科において、知的障害と小奇形を伴う2歳女児の遺伝学的解析を行い、均衡型転座：46,XX,t(7,13)(q11.23;q12.3) とともに、13q13.3に neurobeachin (NBEA)を含む17遺伝子が存在する領域（3,2Mb）の欠失を見いだした。