Letterer-Siwe disease
Encyclopedia
Letterer–Siwe disease is a genetic disorder
considered to be a type of histiocytosis
(a condition where histiocytes proliferate in the body). It is sometimes classified as a form of Langerhans cell histiocytosis
, or as a form of histiocytosis X. It is most commonly seen in children less than two years old. The disorder is believed to be inherited in an autosomal
recessive pattern.
It is named for Erich Letterer and Sture Siwe.
, hepatosplenomegaly
, and seborrhea-like lesions on the skin.
Letterer–Siwe disease is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder is located on an autosome
, and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry
one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.
Genetic disorder
A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....
considered to be a type of histiocytosis
Histiocytosis
In medicine, histiocytosis refers to an excessive number of histiocytes, , and is typically used to refer to a group of rare diseases which share this as a characteristic...
(a condition where histiocytes proliferate in the body). It is sometimes classified as a form of Langerhans cell histiocytosis
Langerhans cell histiocytosis
Langerhans cell Histiocytosis is a rare disease involving clonal proliferation of Langerhans cells, abnormal cells deriving from bone marrow and capable of migrating from skin to lymph nodes...
, or as a form of histiocytosis X. It is most commonly seen in children less than two years old. The disorder is believed to be inherited in an autosomal
Autosome
An autosome is a chromosome that is not a sex chromosome, or allosome; that is to say, there is an equal number of copies of the chromosome in males and females. For example, in humans, there are 22 pairs of autosomes. In addition to autosomes, there are sex chromosomes, to be specific: X and Y...
recessive pattern.
It is named for Erich Letterer and Sture Siwe.
Signs and symptoms
Symptoms include lymphadenopathyLymphadenopathy
Lymphadenopathy is a term meaning "disease of the lymph nodes." It is, however, almost synonymously used with "swollen/enlarged lymph nodes". It could be due to infection, auto-immune disease, or malignancy....
, hepatosplenomegaly
Hepatosplenomegaly
Hepatosplenomegaly is the simultaneous enlargement of both the liver and the spleen . Hepatosplenomegaly can occur as the result of acute viral hepatitis or infectious mononucleosis, or it can be the sign of a serious and life threatening lysosomal storage disease...
, and seborrhea-like lesions on the skin.
Genetics
Autosome
An autosome is a chromosome that is not a sex chromosome, or allosome; that is to say, there is an equal number of copies of the chromosome in males and females. For example, in humans, there are 22 pairs of autosomes. In addition to autosomes, there are sex chromosomes, to be specific: X and Y...
, and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry
Genetic carrier
A genetic carrier , is a person or other organism that has inherited a genetic trait or mutation, but who does not display that trait or show symptoms of the disease. They are, however, able to pass the gene onto their offspring, who may then express the gene...
one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.