Molecular cytogenetic characterization of a de novo chromosome 1q41-q42.11 microdeletion of paternal origin in a 15-year-old boy with mental retardation, developmental delay, autism and congenital heart defects.

Objective: We present molecular cytogenetic characterization of a de novo chromosome 1q41-q42.11 microdeletion of paternal origin in a mentally retarded child of a family requesting for genetic counseling of the future pregnancy.

Case Report: A 43-year-old, gravida 1, para 1, woman, who had a 15-year-old son with mental retardation, planned to have another normal child and requested for genetic counseling of the future pregnancy. Her husband was 48 years old. The 15-year-old boy had a body height of 148 cm (<3rd centile) and a body weight of 40 Kg (<35th centile). He had facial dysmorphism, mental retardation, scoliosis, abnormal gaits, tetralogy of Fallot, pulmonary stenosis and autism but did not have any history of epilepsy. Cytogenetic analysis of the boy and the parents revealed normal karyotypes. Array comparative genomic hybridization (aCGH) analysis of the family revealed a de novo 2.028-Mb 1q41-q42.11 microdeletion, or arr 1q41q42.11 (222,571,596-224,599,234) × 1.0 [GRCh37 (hg19)], encompassing 13 Online Mendelian Inheritance in Man (OMIM) genes including DISP1, SUSD4, FBXO28, TP53BP2 and WDR26 in the child. Quantitative fluorescent polymerase chain reaction analysis confirmed a paternal origin of the deletion. Fluorescence in situ hybridization analysis confirmed a 1q41 deletion.

Conclusion: Genetic counseling of the parents who have a previous child with mental retardation and who wish to have another normal child in the future pregnancy should include genetic studies, and aCGH is useful under such a circumstance.