[Phenotypic and genetic analysis of four patients with 13q33-q34 microdeletion].

Objective: To explore the correlation between 13q33-q34 microdeletion and clinical phenotype.

Methods: Routine chromosomal banding was performed to analyze the karyotype, while array-based comparative genomic hybridization (aCGH array) and single nucleotide polymorphism array(SNP array) were employed to investigate the genome copy number variations.

Results: The karyotype of patient 1 was 46, XY, 9qh+,13qs. Patient 2 showed 46, XX, der (13). Patient 3 showed 46, XX, r(13) (p11.2q32) [43]/45, XX, 13[4]/46, XX, r(13;13) [2]/47, XX, 2r(13;13) [1]. Patient 4 did not undergo chromosome karyotyping analysis. Array analysis showed that four patients have different microdeletions in 13q33-34 region and had common features of 13q33-q34deletion including intellectual disability, facial dysmorphism, microcephaly, hypotonia, low birth weight and genital abnormality.

Conclusion: The severity of phenotypes showed no correlation with the size of deletion in 13q33-q34. The lower percentage of patients with congenital heart disease suggested a complex pathogenesis of such disease. EFNB2, LIG4 and SOX1 in 13q33-34 region are promising candidates for mental retardation. LIG4 was also a likely candidate for microcephaly.