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.
Affected individuals may also have weak deep tendon reflexes, such as the reflex being tested when a doctor taps the knee with a hammer. Some people with HSAN2 experience a diminished sense of taste due to the loss of a type of taste bud on the tip of the tongue called lingual fungiform papillae. Type 2, congenital sensory neuropathy (also historically known as Morvans disease), is characterized by onset of symptoms in early infancy or childhood. Upper & lower extremities are affected with chronic ulcerations and multiple injuries to fingers and feet. Pain sensation is affected predominantly and deep tendon reflexes are reduced. Autoamputation of the distal phalanges is common and so is neuropathic joint degeneration. The NCV shows reduced or absent sensory nerve action potentials and nerve biopsy shows total loss of myelinated fibers and reduced numbers of unmyelinated fibers. It is inherited as an autosomal recessive condition. Genes related to Hereditary sensory and autonomic neuropathy Type 2:
There are two types of HSAN2, called HSAN2A and HSAN2B, each caused by mutations in a different gene. HSAN2A is caused by mutations in the WNK1 gene, and HSAN2B is caused by mutations in the RETREG1 gene (FAM134B). Although two different genes are involved, the signs and symptoms of HSAN2A and HSAN2B are the same. The WNK1 gene provides instructions for making multiple versions (isoforms) of the WNK1 protein. HSAN2A is caused by mutations that affect a particular isoform called the WNK1/HSN2 protein.