Chromosome 1q21.1 – Microdeletion

What is Chromosome 1q21.1 – Microdeletion?

This rare disease is a genetic syndrome that occurs due to microdeletions on a specific chromosome.

It affects the development of affected individuals, especially their motor skills development.

Some individuals diagnosed with microdeletion show no symptoms of the syndrome at all, the reasons for this are still being researched.

There are less than 50 reported cases of the syndrome worldwide, to date.

What gene changes cause Chromosome 1q21.1 – Microdeletion?

The syndrome occurs when small pieces of DNA are deleted from chromosome 1 in each cell.

It is inherited in an autosomal dominant pattern, and about 50% of cases are inherited.

In the case of autosomal dominant inheritance just one parent is the carrier of the gene mutation, and they have a 50% chance of passing it onto each of their children. Syndromes inherited in an autosomal dominant inheritance are caused by just one copy of the gene mutation.

Microdeletion inheritance occurs when there is a deletion of several genes on a chromosome. The specific chromosome on which the deletions occur will determine the syndrome they cause.

What are the main symptoms of Chromosome 1q21.1 – Microdeletion?

75% of children with the syndrome will have developmental delay. This generally affects the development of their motor skills but is often mild in most cases.

Facial features associated with this syndrome are a prominent forehead, a large rounded nasal tip, a long philtrum, high arched palate, a very small head, short stature and cataracts (a clouding of the lens).

Seizures and hypotonia (low muscle tone) are also reasonably common symptoms of the syndrome.

Some individuals experience behavioral conditions, including ADHD, autism spectrum disorder. Individuals with the syndrome may also be at higher risk of developing schizophrenia.

How does someone get tested for Chromosome 1q21.1 – Microdeletion?

The initial testing for Chromosome 1q21.1 - Microdeletion syndrome can begin with facial analysis screening, through the FDNA Telehealth telegenetics platform, which can identify the key markers of the syndrome and outline the need for further testing. A consultation with a genetic counselor and then a geneticist will follow.

Based on this clinical consultation with a geneticist, the different options for genetic testing will be shared and consent will be sought for further testing.

Medical information on Chromosome 1q21.1 – Microdeletion

About 20 patients with microdeletions were reported by Brunetti-Pierri et al., (2008). The phenotype varied from normality (often in a parent) to significant disease in a child. As with microduplications of the same segment, neuropsychiatric problems were frequent. TAR (see elsewhere) can be caused by 1q21.1 microdeletions (Guastadisegni et al., 2012). A family with 3 affected (Digilio et al., 2013), had the proband with pulmonary stenosis, an ASD and VSD and hismaternal uncle with pulmonary stenosis. This deletion might occur in sporadic non-syndromal pulmonary stenosis (1 out of 27 cases).

* This information is courtesy of the L M D.
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