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Hereditary Sensory and Autonomic Neuropathy Type II.

Authors

Kurth I1.

Source

GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2020.
2010 Nov 23 [updated 2015 Feb 19].

Author information

1
Institute of Human Genetics, University Hospital Jena, Jena, Germany

Excerpt

CLINICAL CHARACTERISTICS:

Hereditary sensory and autonomic neuropathy type II (HSAN2) is characterized by progressively reduced sensation to pain, temperature, and touch. Onset can be at birth and is often before puberty. The sensory deficit is predominantly distal with the lower limbs more severely affected than the upper limbs. Over time sensory function becomes severely reduced. Unnoticed injuries and neuropathic skin promote ulcerations and infections that result in spontaneous amputation of digits or the need for surgical amputation. Osteomyelitis is common. Painless fractures can complicate the disease. Autonomic disturbances are variable and can include hyperhidrosis, tonic pupils, and urinary incontinence in those with more advanced disease.

DIAGNOSIS/TESTING:

Diagnosis is based on clinical findings and molecular genetic testing of WNK1 (previously HSN2) (type HSAN2A), RETREG1 (previously FAM134B, JK1) (type HSAN2B), KIF1A (type HSAN2C), and SCN9A (type HSAN2D), the only genes in which mutation is known to cause HSAN2.

MANAGEMENT:

Treatment of manifestations: Treatment is symptomatic and often involves a team including neurologists, orthopedic surgeons, and physiotherapists. Training in the care of the sensory-impaired limb, often in a diabetic clinic, is important and includes self-examination especially of the feet for any signs of trauma. To prevent osteomyelitis, and hence amputations, wounds require cleaning and protection along with antiseptic treatment. To prevent callous formation the skin of neuropathic limbs requires hydration and lipid-based unguents. Appropriate shoes and socks are recommended. Surveillance: The feet should be inspected daily for injuries or sources of wear. Annual follow up in centers with comprehensive care of diabetics and/or persons with Charcot-Marie-Tooth neuropathy is recommended. Agents/circumstances to avoid: Ill-fitting shoes or other sources of trauma to the feet or hands (e.g., use protective gloves when handling hot items when cooking).

GENETIC COUNSELING:

HSAN2, which includes HSAN2A, HSAN2B, HSAN2C, and HSAN2D, is inherited in an autosomal recessive manner. At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Carrier testing of at-risk relatives and prenatal diagnosis for pregnancies at increased risk are possible if the pathogenic variants in the family are known.

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