Coffin-Lowry syndrome
Encyclopedia
Coffin-Lowry syndrome is a genetic disorder
that is X-linked dominant
and which causes severe mental problems sometimes associated with abnormalities of growth, cardiac abnormalities, kyphoscoliosis
, as well as auditory and visual abnormalities.
Coffin-Lowry syndrome was independently described by Dr. Coffin and his associates in 1966 and later described by Dr. Lowry and associates in 1971. Dr. Temtamy showed that the cases represented a single syndrome in 1975.
s in the RPS6KA3
gene
. This gene is located on the short arm of the X chromosome
(Xp22.2). The RPS6KA3 gene makes a protein
that is involved with signaling within cell
s. Researchers believe that this protein helps control the activity of other genes and plays an important role in the brain. The protein is involved in cell signaling pathways that are required for learning, the formation of long-term memories, and the survival of nerve cells. The protein RSK2 which is encoded by the RPS6KA3 gene is a kinase which phosphorylates some substrates like CREB and histone H3. RSK2 is involved at the distal end of the Ras/MAPK signaling pathway. Mutations in the RPS6KA3 disturb the function of the protein, but it is unclear how a lack of this protein causes the signs and symptoms of Coffin-Lowry syndrome. At this time more than 120 mutations have been found. Some people with the features of Coffin-Lowry syndrome do not have identified mutations in the RPS6KA3 gene. In these cases, the cause of the condition is unknown.
This condition is inherited in an X-linked dominant pattern. A condition is considered X-linked if the gene that causes the disorder is located on the X chromosome (one of the two sex chromosomes). The inheritance is dominant if one copy of the altered gene is sufficient to cause the condition. In most cases, males experience more severe symptoms of the disorder than females. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
A majority of boys with Coffin-Lowry syndrome have no history of the condition in their families. These cases are caused by new mutations in the RPS6KA3 gene (de novo mutations). A new mutation means that neither parent has the altered gene, but the affected individual could pass it on to his children.
.
Patients may also have an underdeveloped upper jaw bone, abnormally prominent brows, or widely spaced eyes.
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....
that is X-linked dominant
X-linked dominant
X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome. As an inheritance pattern, it is less common than the X-linked recessive type...
and which causes severe mental problems sometimes associated with abnormalities of growth, cardiac abnormalities, kyphoscoliosis
Kyphoscoliosis
Kyphoscoliosis describes an abnormal curvature of the spine in both a coronal and sagittal plane. It is a combination of kyphosis and scoliosis. Kyphoscoliosis is a musculoskeletal disorder causing chronic underventilation of the lungs and may be one of the major causes of pulmonary hypertension...
, as well as auditory and visual abnormalities.
History
It was characterized by Grange S. Coffin (1923– )in 1966 and Robert Brian Lowry (1932– ) in 1971.Coffin-Lowry syndrome was independently described by Dr. Coffin and his associates in 1966 and later described by Dr. Lowry and associates in 1971. Dr. Temtamy showed that the cases represented a single syndrome in 1975.
Causes
The syndrome is caused by mutationMutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
s in the RPS6KA3
RPS6KA3
Ribosomal protein S6 kinase, 90kDa, polypeptide 3, also known as RPS6KA3, is an enzyme that in humans is encoded by the RPS6KA3 gene.- Function :This gene encodes a member of the RSK family of serine/threonine kinases...
gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
. This gene is located on the short arm of the X chromosome
X chromosome
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...
(Xp22.2). The RPS6KA3 gene makes a protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
that is involved with signaling within cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
s. Researchers believe that this protein helps control the activity of other genes and plays an important role in the brain. The protein is involved in cell signaling pathways that are required for learning, the formation of long-term memories, and the survival of nerve cells. The protein RSK2 which is encoded by the RPS6KA3 gene is a kinase which phosphorylates some substrates like CREB and histone H3. RSK2 is involved at the distal end of the Ras/MAPK signaling pathway. Mutations in the RPS6KA3 disturb the function of the protein, but it is unclear how a lack of this protein causes the signs and symptoms of Coffin-Lowry syndrome. At this time more than 120 mutations have been found. Some people with the features of Coffin-Lowry syndrome do not have identified mutations in the RPS6KA3 gene. In these cases, the cause of the condition is unknown.
This condition is inherited in an X-linked dominant pattern. A condition is considered X-linked if the gene that causes the disorder is located on the X chromosome (one of the two sex chromosomes). The inheritance is dominant if one copy of the altered gene is sufficient to cause the condition. In most cases, males experience more severe symptoms of the disorder than females. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
A majority of boys with Coffin-Lowry syndrome have no history of the condition in their families. These cases are caused by new mutations in the RPS6KA3 gene (de novo mutations). A new mutation means that neither parent has the altered gene, but the affected individual could pass it on to his children.
Prognosis
There is no cure and no standard course of treatment for Coffin-Lowry syndrome. Treatment is symptomatic and supportive, and may include physical and speech therapy and educational services.Growth
In utero growth is normal but post natal growth is retarded. Patients are sometimes microcephalicMicrocephaly
Microcephaly is a neurodevelopmental disorder in which the circumference of the head is more than two standard deviations smaller than average for the person's age and sex. Microcephaly may be congenital or it may develop in the first few years of life...
.
Skeleton
Progressive kyphoscoliosis affects 1 in 2 patients. Micrognathia is also associated with this syndrome.Patients may also have an underdeveloped upper jaw bone, abnormally prominent brows, or widely spaced eyes.
Vision and audition
Auditory abnormalities are frequent and often present. Vision abnormalities are not often present.External links
- http://ghr.nlm.nih.gov/condition/coffin-lowry-syndrome
- http://www.wrongdiagnosis.com/c/coffin_lowry_syndrome/symptoms.htm