People with 17q12 microdeletions who have normal fertility have a 50% chance of passing the deletion down to their offspring. Environmental factors have not been implicated in the syndrome. Diagnosis
Like other chromosomal microdeletions, 17q12 microdeletion syndrome is diagnosed via fluorescence in situ hybridization. Traditional karyotyping, used to diagnose major chromosomal disorders such as aneuploidy, is rarely sensitive enough to detect microdeletions. Treatment
As the underlying 17q12 microdeletion is an innate genetic disorder, it cannot by itself be treated. Rather, treatment is symptomatic and supportive. The high prevalence of kidney disease indicates routine monitoring of renal function, particularly in people taking potentially nephrotoxic medications such as lithium. The comorbities involved in 17q12 microdeletion syndrome require caution in medical treatment; for instance, the increased risk of diabetes requires strict monitoring for post-transplantation diabetes mellitus in kidney transplant patients, as does the risk of weight gain and diabetes from neuroleptic drugs in those with a mental health diagnosis. Epidemiology
The prevalence of 17q12 microdeletion syndrome is unknown, and it is likely to be underdiagnosed. 17q12 microdeletions are estimated to occur in approximately 1 in 600 people on the autism spectrum and 1 in 1,600 with schizophrenia, but are far rarer in the general population. General prevalence is estimated to be between 1 in 14,000 and 1 in 62,500.In addition to the increased prevalence in autism and schizophrenia, some other clinical populations have increased prevalence of 17q12 microdeletion syndrome. The condition occurs in approximately 2% of those with congenital kidney abnormalities and 3-6% of women with Müllerian agenesis.
17q12 microdeletion syndrome, also known as 17q12 deletion syndrome, is a rare chromosomal anomaly caused by the deletion of a small amount of material from a region in the long arm of chromosome 17. It is typified by deletion of the HNF1B gene, resulting in kidney abnormalities and renal cysts and diabetes syndrome. It also has neurocognitive effects, and has been implicated as a genetic factor for autism and schizophrenia. 17q12 microdeletion syndrome is not to be confused with 17q12 microduplication syndrome, caused by the addition of genetic material in the same region from which it is removed in the microdeletion, or 17q21.31 microdeletion syndrome, another name for Koolen–De Vries syndrome. Presentation
17q12 microdeletions have a variable phenotype, ranging from few or no symptoms to severe disability. The condition is thought to be underdiagnosed, and cases with milder phenotypes may not reach clinical attention unless they have an affected child themselves. The most characteristic symptom is renal cysts and diabetes syndrome (RCAD), also known as "type 5 diabetes", which is caused by deletion of the associated HNF1B gene in the region. RCAD is associated with kidney abnormalities and a characteristic form of diabetes that causes atrophy of the pancreas. However, some people with 17q12 microdeletions have normal renal function. RCAD is diagnosed in approximately 40% of people with 17q12 microdeletions, usually prior to age 25, while kidney abnormalities more broadly occur in approximately 85-90%.People with 17q12 microdeletions have a characteristic facial phenotype, albeit a subtle one not usually obvious in daily life.