Genetics


Genetics

The gene responsible for Alström Syndrome was discovered by scientists at the Jackson Laboratory in Maine, USA, and scientists at Southampton University, England, simultaneously.

The ALMS1 gene provides instructions for making a protein, of which the function is unknown. Researchers believe that the protein may play a role in hearing, vision, regulation of body weight, and functions of the heart, kidney, lungs, and liver. It may also affect how the pancreas regulates insulin, a hormone that helps control blood sugar levels.The gene responsible for Alström Syndrome was discovered by scientists at the Jackson Laboratory in Maine, USA, and scientists at Southampton University, England, simultaneously.

Alström Syndrome is an autosomal recessive condition meaning that both parents must carry one copy of the ALMS1 gene with a significant mutation to have an affected child. There is a 1 in 4 chance of having an affected child with each pregnancy.

Almost all of our genes come in pairs, one inherited from each of our parents. Most parents are not aware that they carry an alteration in ALMS1 gene until the birth of an affected child.  Carriers of Alström Syndrome have one copy of the altered or mutated gene, but do not have any visible symptoms of Alström Syndrome. A recessive condition like  Alström Syndrome results when a child inherits two copies of the altered ALMS1, one from each parent. Both parents must be carriers in order for any of their children to be affected.   Couples in which the man and the woman are each carriers of an alteration in ALMS1, have a 25% chance with each pregnancy of conceiving a child with Alström Syndrome. There is a 50% chance of producing a child who is a carrier like the parents and a 25% chance that the child will be neither a carrier or affected. Please see the diagram below:

One fifth of the world’s population live in communities where consanguineous marriages are common (of the same blood origin). In the UK, these include those of Pakistani, Middle Eastern, Bangladeshi, Turkish and some groups of Indian origin, plus Irish travellers and some refugees. ASUK has built supportive relationships within these communities to support families, no matter what their race or cultural background.

 Where an autosomal recessive condition like Alström Syndrome is identified within these populations, parents and extended family members are at increased risk of having additional children affected.

Within Bangladeshi, Turkish and some groups of Indian origin, plus Irish travellers and some refugees there are consanguineous marriages, recessively inherited disorders like AS tend to cluster in extended families that are connected by familial links based on blood ties, consolidated through marriage.

Genetic counselling is available locally and can be accessed via the AS specialised multi-disciplinary clinics in Birmingham. This can provide the whole family with relevant information to enable them to make informed choices about future pregnancies and to help them understand the genetic basis of the condition.

An introductory guide, Consanguineous Marriage and Inherited Disorders is now available from Dr Aamra Darr BSc (Hons), PhD, Director of Genetics Communication Diversity (GCD) here.

ASUK has built supportive relationships and works within all communities to support all families affected, no matter what their race of cultural background. For further information, contact Kerry
Leeson-Beevers on 01709 210151 or email kerry.leeson@alstrom.org.uk

Genetic Alliance UK can help families who may be worried that they will pass on a genetic condition to their child.

Further information about genetics is provided by Genetic Alliance UK with specific information sheets available to download. Please follow the link to their website to find out more https://www.geneticalliance.org.uk/information/

Media Reviewed: March 2017
Next Review: March 2019