Autosomal Dominant: Marfan Syndrome Autosomal Dominant: Marfan Syndrome Genes are inherited from our biological parents in specific ways. One of the basic patterns of inheritance of our genes is called autosomal dominant inheritance. W...
Autosomal Recessive: Cystic Fibrosis, Sickle Cell Anemia, Tay Sachs Disease Autosomal Recessive: Cystic Fibrosis, Sickle Cell Anemia, Tay-Sachs Disease Genes are inherited from our biological parents in specific ways. One of the basic patterns of inheritance of our genes is ...
Before Your Next Pregnancy Before Your Next Pregnancy What to do before (and during) your next pregnancy to lessen the chance for birth defects? If you are planning to become pregnant, taking certain steps can help reduce risk...
Biochemical Genetic Testing Biochemical Genetic Testing What is biochemical genetic testing? Biochemical genetic testing involves the study of enzymes in the body that may be abnormal in some way. The enzymes may be deficient o...
Chance a Chromosome Abnormality Will Occur Again: Numerical, Structural (Inherited and De Novo), Mosaicism Chance a Chromosome Abnormality Will Occur Again: Numerical, Structural (Inherited and De Novo), Mosaicism What is the chance for a chromosome abnormality to happen again? The chance for a chromosome...
Chromosome Abnormalities Chromosome Abnormalities There are many different types of chromosome abnormalities that require clinical care by a physician or other healthcare professional. Listed in the directory below are some,...
Chromosome Studies: Karyotype, Extended Banding, Fluorescence In Situ Hybridization (FISH), and Chromosomal Microarray Analysis Chromosome Studies: Karyotype, Extended Banding, Fluorescence In Situ Hybridization (FISH), and Chromosomal Microarray Analysis What type of testing is available to determine whether a child has a ge...
Down Syndrome (Trisomy 21) Down Syndrome (Trisomy 21) What are trisomies? The term trisomy is used to describe the presence of three chromosomes, rather than the usual matched pair of chromosomes. For example, if a baby is bor...
Dyskeratosis Congenita Dyskeratosis Congenita Dyskeratosis congenita is a congenital disease, meaning it is present at birth. It was initially thought to only affect the skin and nails, but today experts understand that dy...
Evaluating a Child for Birth Defects Evaluating a Child for Birth Defects There are many tests that help to evaluate a child for birth defects. Listed in the directory below are some, for which we have provided a brief overview. Overvie...
Examples of Nonteratogenic Agents Examples of Nonteratogenic Agents A nonteratogenic agent is one which does not cause birth defects. What are some examples of nonteratogenic agents? Spermicides. Spermicides are agents which impair t...
Examples of Teratogens Examples of Teratogens There are many different examples of teratogens that cause birth defects. Listed in the directory below are some, for which we have provided a brief overview. Fetal Alcohol Syn...
Fetal Alcohol Syndrome Fetal Alcohol Syndrome What is fetal alcohol syndrome (FAS)? An infant born to a mother who drinks alcohol during pregnancy can have problems included in a group of disorders called fetal alcohol spe...
Genetic Services for Children: When, Where, How Genetic Services for Children: When, Where, How When does a child need genetic services? There are many features that can be present in a child which would indicate a referral is needed for genetic s...
Glossary - Medical Genetics Glossary - Medical Genetics | A | | B | | C | | D | | E | | F | | G | | H | | I | | J | | K | | L | | M | | N | | O | | P | | Q | | R | | S | | T | | U | | V | | W | | X | | Y | | Z | A back to top a...
Home Page - Medical Genetics Topic Index Overview of Birth Defects Chromosome Abnormalities Single Gene Defects The Difference Between a Chromosome Abnormality and a Single Gene Defect Multifactorial Inheritance Teratogens Non-T...
How Chromosome Abnormalities Happen: Meiosis, Mitosis, Maternal Age, Environment How Chromosome Abnormalities Happen: Meiosis, Mitosis, Maternal Age, Environment How do chromosome abnormalities happen? Chromosome abnormalities typically occur as a result of one, or more, of the f...
Identification, Treatment, and Prevention of Birth Defects Identification, Treatment, and Prevention of Birth Defects Identifying, treating, and preventing birth defects has been and continues to be a primary goal of genetic research. The Human Genome Projec...
Identifying Teratogens Identifying Teratogens What studies are conducted to determine whether an agent is a teratogen? The following studies may be conducted to determine whether or not an agent is a teratogen: Animal stud...
Medical History and Genetic Testing Medical History and Genetic Testing To evaluate a child for birth defects, health care providers not only look at a child's newborn screening test results, but also look at the prenatal history of th...
Mitochondrial Inheritance: Leber's Optic Atrophy Mitochondrial Inheritance: Leber's Optic Atrophy What is mitochondrial inheritance? The normal 46 chromosomes in our body are contained in the center of our cells, which is called the nucleus. Mitoch...
Mosaic Down Syndrome Mosaic Down Syndrome What is mosaic Down syndrome? Mosaicism, used to describe the presence of more than one type of cell in a person, is usually described as a percentage. For example, when a baby i...
Mosaicism Mosaicism What is mosaicism? The term mosaicism is used to describe the presence of more than one type of cell in a person. For example, a person may have some of the cells in their body with 46 chro...
Multifactorial Inheritance and Birth Defects Multifactorial Inheritance What is multifactorial inheritance? Multifactorial inheritance means that many factors are involved in causing a birth defect. The factors are usually both genetic and envi...
Nontraditional Inheritance Nontraditional Inheritance Inheritance patterns that do not fall into the chromosomal, single-gene, or multifactorial categories, are referred to as "nontraditional." Listed in the directory below ar...
Numerical Abnormalities: Overview of Trisomies and Monosomies Numerical Abnormalities: Overview of Trisomies and Monosomies What are numerical chromosome abnormalities? Numerical abnormalities are one type of chromosome abnormality. These types of birth defects...
Online Resources - Medical Genetics Online Resources - Medical Genetics This website was compiled from a variety of sources including many of the online resources listed below, but is not intended to substitute or replace the professio...
Other Arrangements: Rings and Inversions Other Arrangements: Rings and Inversions What is an inversion? There are other ways in which the structure of a chromosome can be altered. One example is called an "inversion." The term "inversion" i...
Overview of Birth Defects Overview of Birth Defects What is a birth defect? A "birth defect" is a health problem or physical change, which is present in a baby at the time he or she is born. Birth defects may be very mild, wh...
Overview of Chromosome Abnormalities Overview of Chromosome Abnormalities What is a chromosome? The human body is made up of cells. For example, when you have a sunburn and your skin peels, then you are shedding skin "cells." In the cen...
Overview of Newborn Screening for Birth Defects Overview of Newborn Screening for Birth Defects What is newborn screening? "State newborn screening" refers to a test performed on every baby born in every state of the country within the first few d...
Overview of Single Gene Defects Overview of Single Gene Defects What are genes? Genes are what determine your traits, such as eye color and blood type. They are contained on our chromosomes, which normally number 46 (23 pairs) in e...
Phenytoin (Dilantin) Phenytoin (Dilantin) What is Phenytoin (Dilantin)? Phenytoin (or Dilantin) is a medication used to treat epilepsy (seizure disorder). If Phenytoin is taken by the mother in the first trimester, there...
Single Gene Defects Single Gene Defects There are many different single gene defects that require clinical care by a physician or other healthcare professional. Listed in the directory below are some, for which we have ...
Structural Abnormalities: Deletions (Cri du Chat) and Duplications (Pallister Killian) Structural Abnormalities: Deletions (Cri du Chat) and Duplications (Pallister Killian) What are structural chromosome abnormalities? Structural chromosome abnormalities occur when there is a change i...
Studies for Single Gene Defects: DNA (Direct and Indirect) Studies for Single Gene Defects: DNA (Direct and Indirect) What are the different studies for single gene defects? Genes are made up of the chemical DNA. To study genes, you have to analyze the DNA t...
Support Groups Support Groups This page contains links to other Internet sites with information about support groups for parents affected by a birth defect. We hope you find these sites helpful, but please remember...
Teratogens Teratogens Teratogens are substances found the in the environment that can cause a birth defect. There are many different teratogens, and some are listed in the directory below are some, for which we...
Teratogens Overview Teratogens Overview What is a teratogen? A teratogen is an agent that can cause or increase the chance of a birth defect. It is usually something in the environment that the mother may be exposed to ...
Testing for Birth Defects Testing for Birth Defects There are many types of tests that may be performed to determine whether a child has a genetic birth defect. Listed in the directory below are some, for which we have provid...
The Difference Between a Chromosome Abnormality and a Single Gene Defect The Difference Between a Chromosome Abnormality and a Single Gene Defect What is the difference between a chromosome abnormality and a single gene defect? There are approximately 25,000 genes contain...
The Human Genome Project The Human Genome Project The Human Genome Project (HGP), according to the National Human Genome Research Institute, was the international, collaborative research program formed to complete the mappin...
Topic Index - Medical Genetics Topic Index - Medical Genetics Medical Genetics Home Overview of Birth Defects Chromosome Abnormalities Overview of Chromosome Abnormalities Types of Chromosome Abnormalities Numerical Abnormalities:...
Translocation Down Syndrome Translocation Down Syndrome What is translocation Down syndrome? Translocation Down syndrome refers to the type of Down syndrome that is caused by rearranged chromosome material. In this case, there ...
Translocations Translocations What are translocations? The term translocation is used when the location of specific chromosome material changes. There are two main types of translocations: reciprocal and Robertsoni...
Trinucleotide Repeats: Fragile X Syndrome Trinucleotide Repeats: Fragile X Syndrome What are trinucleotide repeats? DNA, the chemical that makes up our genes, contains a "code" of three letter words known as "codons" or "trinucleotide repeat...
Types of Chromosome Abnormalities Types of Chromosome Abnormalities There are many different types of chromosome abnormalities that require clinical care by a physician or other healthcare professional. Listed in the directory below ...
Uniparental Disomy: Prader-Willi Syndrome, Angelman Syndrome Uniparental Disomy: Prader-Willi Syndrome, Angelman Syndrome What is uniparental disomy? Normally, we inherit one copy of each chromosome pair from our biological mother, and the other copy of the ch...
Uses of Genetic Testing Uses of Genetic Testing What are the uses of genetic testing which may be important for me to know? Diagnostic testing Diagnostic testing is used to identify or confirm the diagnosis of a disease or ...
Varicella and Pregnancy Varicella and Pregnancy What is varicella? Varicella (or chickenpox) is a highly infectious disease, usually associated with childhood. By adulthood, the vast majority of Americans have had chickenpo...
Vitamin, Gene, and Enzyme Replacement Therapy Vitamin, Gene, and Enzyme Replacement Therapy How is vitamin, gene, and enzyme replacement therapy useful in the identification, treatment, and prevention of birth defects? Vitamin therapy. There is ...
When to Seek Genetic Counseling When to Seek Genetic Counseling Genetic counseling is a professional assessment of a person's or couple's risk factors regarding their family history, medical history, and/or pregnancy history. The g...
X-linked Dominant: Incontinentia Pigmenti X-linked Dominant: Incontinentia Pigmenti Genes are inherited from our biological parents in specific ways. One of the basic patterns of inheritance of our genes is called X-linked dominant inheritan...
X-linked Recessive: Red-Green Color Blindness, Hemophilia A X-linked Recessive: Red-Green Color Blindness, Hemophilia A Genes are inherited from our biological parents in specific ways. One of the basic patterns of inheritance of our genes is called X-linked ...