Thursday, November 26, 2015
Inherited Disorders and Birth Defects
Chromosome - missing 7 & 11
A coworkers granddaughter was told by a doctor that she was missing chromosome 7 & 11. I am trying to find information to help her better understand what this means. Her granddaughter holds her head to one side, doesn`t speak and her development is very slow.
Most likely the problem is that your co-worker’s granddaughter is missing a piece of one of her chromosome 7s and piece of chromosome 11. I do not know of any babies being born that are missing an entire chromosome 7 or 11 - those pregnancies would miscarry.
In all of the cells of our bodies, there are structures called chromosomes which carry the genes that tell our bodies how to develop and function. Each cell should have 46 chromosomes except for sperm and eggs - they only have 23 chromosomes. Chromosomes come in pairs – a person inherits half of his chromosomes from his mother and half from his father. 44 of the chromosomes are called autosomes – non-sex chromosomes; and 2 chromosomes are the sex chromosomes – females have 2 X chromosomes and males have an X and a Y chromosome.
Occasionally, when cells divide they do not divide correctly and a piece of a chromosome could break off and be lost. This is called a deletion (missing a part). If this happens at the time of conception, it leads to problems in growth, development, mental retardation and can cause birth defects. The specific type of problems your co-worker’s granddaughter may have will depend on what piece of chromosome 7 and 11 are missing and how much is missing. The extent of the problems and mental retardation (how severe it is) is variable and depends on the individual child.
Hopefully your co-worker’s granddaughter’s parents have talked to a geneticist or genetic counselor to obtain specific information about this chromosome abnormality.
There is a very good website called Chromosome Deletion Outreach that has an excellent overview of chromosomes and different chromosome abnormalities.
Anne Matthews, RN, PhD
Associate Professor of Genetics
School of Medicine
Case Western Reserve University