If the syndrome was found in the family, chances of a second child with the syndrome are 50%, because the syndrome is autosomal dominant. The effect of the syndrome on the child cannot be predictedThe syndrome can be detected with fluorescence in situ hybridization. For parents with a child with the syndrome, it is advisable to consult a physician before another pregnancy. Management
Treatment of cause: Due to the genetic cause, no treatment of the cause is possible.Treatment of manifestations: routine treatment of ophthalmologic, cardiac, and neurologic findings; speech, occupational, and physical therapies as appropriate; specialized learning programs to meet individual needs; antiepileptic drugs or antipsychotic medications as needed.Surveillance: routine pediatric care; routine developmental assessments; monitoring of specific identified medical issues. Prevalence
As of October 2012, Unique, an international rare chromosome disorder group and registry, has 64 genetically confirmed cases of this deletion worldwide. Research
On several locations in the world people are studying on the subject of 1q21.1 deletion syndrome. The syndrome was identified for the first time with people with heart abnormalities. The syndrome has later been found in patients with schizophrenia. Research is done on patients with a symptom of the syndrome, to find more patients with the syndrome.There may be a relation between autism and schizophrenia. Literature shows that nine locations have been found on the DNA where the syndromes related to autism or schizophrenia can be found, the so-called "hotspots": 1q21.1, 3q29, 15q13.3, 16p11.2, 16p13.1, 16q21, 17p12, 21q11.2 and 21q13.3.
This part of 1q21.1 is involved in the development of the brain. It is assumed to be a dosage-sensitive gene. When this gene is not available in the 1q21.1 area, it leads to microcephaly. HYDIN2 is a recent duplication (found only in humans) of the HYDIN gene found on 16q22.2. Research on the genes CHD1L and PRKAB2 within lymphoblast cells  lead to the conclusion that anomalies appear with the 1q21.1-deletion syndrome:

CHD1L is an enzyme which is involved in untangling the chromatides and the DNA repair system. With 1q21.1 deletion syndrome a disturbance occurs, which leads to increased DNA breaks. The role of CHD1L is similar to that of helicase with the Werner syndrome
PRKAB2 is involved in maintaining the energy level of cells. With 1q21.1-deletion syndrome this function was attenuated.GJA5 has been identified as the gene that is responsible for the phenotypes observed with congenital heart diseases on the 1q21.1 location. In case of a duplication of GJA5 tetralogy of Fallot is more common. In case of a deletion other congenital heart diseases than tetralogy of Fallot are more common. References
Further reading
External links
DECIPHER database entry for 1q21.1 deletion syndrome
1q21.1 deletion, GeneReviews NCBI Bookshelf
Orpha.net