2q37 monosomy is a rare
genetic disorder
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...
caused by a
deletion of a segment at the end of
chromosome 2
Chromosome 2 is one of the twenty-three pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 2 is the second-largest human chromosome, spanning more than 242 million base pairs and representing almost e ...
.
Signs and symptoms
Almost all people with this syndrome have some degree of
intellectual disability
Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation,Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signifi ...
and
facial dysmorphism
A dysmorphic feature is an abnormal difference in body structure. It can be an isolated finding in an otherwise normal individual, or it can be related to a congenital disorder, genetic syndrome or birth defect. Dysmorphology is the study of dysm ...
(round face, deep-set eyes, thin upper lip). Behavioural problems are common.
Brachymetaphalangism (
metacarpal
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...
or
metatarsal
The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the med ...
shortening) is reported in ~50% of cases overall, but is typically not evident below the age of 2 years. There is striking phenotypic variability, and the size and extent of the deleted region cannot be used as accurate predictors of prognosis. Some patients have additional problems such as
congenital heart disease
A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular ...
and
seizures
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or neural oscillation, synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much o ...
.
Genetics
The minimal deletion causing this syndrome has been defined as a 3 megabase region that contains the genes
GPR35
G protein-coupled receptor 35 also known as GPR35 is a G protein-coupled receptor which in humans is encoded by the ''GPR35'' gene. Heightened expression of GPR35 is found in immune and gastrointestinal tissues, including the crypts of Lieberkühn ...
,
GPC1
Glypican-1 (GPC1) is a protein that in humans is encoded by the ''GPC1'' gene. GPC1 is encoded by human ''GPC1'' gene located at 2q37.3. GPC1 contains 558 amino acids with three predicted heparan sulfate chains.
Function
Cell surface heparan su ...
and
STK25
Serine/threonine-protein kinase 25 is an enzyme that in humans is encoded by the ''STK25'' gene.
Interactions
STK25 has been shown to interact with STRN, PDCD10 and MOBKL3
Mps one binder kinase activator-like 3 is an enzyme that in humans is enco ...
.
Almost all deletions are found to be terminal deletions at the end of chromosome 2. There is a high frequency of ''de novo'' deletions, but multiple cases within a single family are also observed. Equal proportions of maternally and paternally derived
rearrangements were seen in Aldred's series. No common breakpoints for the deletion were identified indicating that the 2q37 rearrangement is unlikely to be mediated by
non-homologous recombination
Illegitimate recombination, or nonhomologous recombination, is the process by which two unrelated double stranded segments of DNA are joined. This insertion of genetic material which is not meant to be adjacent tends to lead to genes being broken ...
and
low-copy repeats.
In a study of 20 patients,
no clear relationship was found between clinical features and the size or position of the
monosomic
Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more complete sets of chromosomes. A cell with any ...
region.
Diagnosis
See also
*
2q37 deletion syndrome
References
External links
*
Genetics home reference for 2q37 deletion syndrome
{{Chromosomal abnormalities
Human genetics
Autosomal monosomies and deletions