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Diseases

Genetic and Rare Diseases Information Center (GARD)

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Split hand split foot nystagmus


Other Names for this Disease
  • Karsch-Neugebauer syndrome
  • KNS
  • Split hand nystagmus syndrome
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Overview



What is split hand split foot nystagmus?

What are the symptoms of split hand split foot nystagmus?

How is split hand split foot nystagmus inherited?

What is the prognosis for split hand split foot nystagmus?


What is split hand split foot nystagmus?

Split hand split foot nystagmus is a rare congenital syndrome characterized by split hand and split foot deformity and eye abnormalities, especially nystagmus. It is thought to have an autosomal dominant mode of inheritance. Currently, the underlying genetic defect has not been identified. The outlook for children with this condition is good.[1]
Last updated: 10/17/2013

What are the symptoms of split hand split foot nystagmus?

People with this condition are born with split hands and feet. Split hands and split foot refers to a developmental malformation consisting of missing digits (fingers and/or toes), a deep median cleft (cleft down the center of the hand or foot), and fusion of remaining digits.[2] People with this syndrome also have rapid involuntary movements of the eyes, called nystagmus.[3] Abnormalities of the teeth can occur rarely.[4]
Last updated: 10/17/2013

How is split hand split foot nystagmus inherited?

Split hand split foot nystagmus is thought to be inherited in an autosomal dominant fashion. A person with an autosomal dominant condition has a 50% chance of passing the condition on to their children.[5] Click here to learn more about autosomal dominant inheritance.

Sometimes a person is the only one in their family with the autosomal dominant disorder. One explanation for this is that the person has a de novo or new mutation. De novo mutations refer to a change in a gene that is present for the first time in one family member as a result of a mutation in the mother’s egg or father’s sperm, or in the fertilized egg itself.

In addition, there have been a couple of case reports where unaffected parents had more than one child with split hand split foot nystagmus. It is thought that this may have been due to germline mosaicism. In germline mosaicism, one of the unaffected parents has the disease-causing genetic mutation in some of his/her eggs or sperm only. Click here to learn more about mosaicism.
Last updated: 11/1/2013

What is the prognosis for split hand split foot nystagmus?

In general, the prognosis of children with split hand split foot nystagmus seems to be favorable.[1] The degree of disability caused by the loss of function in the limbs and by the eye problems, is largely determined by the degree of severity of these defects.[1]
Last updated: 11/1/2013

References
  1. Wong SC, Cobben JM, Hiemstra S, Robinson PH, Heeg M. Karsch-Neugebauer Syndrome in Two Sibs with Unaffected Parents. American Journal of Medical Genetics. January 13, 1998; 75(2):207-210. http://www.ncbi.nlm.nih.gov/pubmed/9450888.
  2. D’Alton ME, Crombleholme TM, Bianchi DW. Ectrodactyly. Fetology. New York, NY: McGraw-Hill; 2000;
  3. Eye Movement - Uncontrollable. MedlinePlus. 2007; http://www.nlm.nih.gov/medlineplus/ency/article/003037.htm. Accessed 10/17/2008.
  4. Mathian VM, Sundaram AM, Karunakaran R et al. J Pharm Bioallied Sci. August 2012; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3467867/. Accessed 10/17/2013.
  5. What are the different ways in which a genetic condition can be inherited?. Genetics Home Reference Web site. September 23, 2013; http://ghr.nlm.nih.gov/handbook/inheritance/inheritancepatterns. Accessed 9/24/2013.