Many genetic diseases occur more frequently in people of certain ethnic backgrounds. That is why it is important to understand how your ethnic background affects your risk to have a child with a genetic disease.

For example, sickle cell disease occurs more commonly in African-Americans, Tay-Sachs disease in people of Ashkenazi (eastern and central European) ancestry, thalassemia in people of Middle Eastern and Mediterranean descent and cystic fibrosis in Caucasians.

Many of these ethnic-based genetic diseases are inherited in an autosomal recessive pattern. This means that two copies of a mutated gene, one from each parent, are necessary to cause the disorder.

People with only one copy of a mutated gene are known as carriers. In most autosomal recessive conditions, carriers do not have any symptoms of the condition and, therefore, are often unaware that they are a carrier until they have a positive carrier test or have an affected child.

The risk of having a child with these genetic diseases is based on the inheritance pattern, as well as both of the parent’s ethnic backgrounds. Couples who are of the same ethnic background may have a higher risk of having a child with autosomal recessive disorders than couples who are of different ethnic backgrounds.

• Couples who are also related to each other by blood, such as cousins, may have an even higher risk.
• A family history of a disorder can also further increase the risk to have an affected child.

Understanding your risk to have an affected child is the first step to making an informed decision about carrier testing before or during your pregnancy. To better understand your risk, you can use our Family Health History tool to analyze your ethnic background and family health history.

Thankfully, most babies are born healthy, but every pregnancy is at risk for a birth defect. That is why is may be helpful to speak with a genetic counselor, a medical professional trained in assessing the risk for birth defects and genetic disorders, before or during your pregnancy.

Two common reasons that people seek prenatal genetic counseling are maternal age and a family history of a hereditary disease.

Maternal Age

As women age, their eggs age, and consequently, their risk of having a child with a chromosome abnormality increases. Down syndrome (also known as Trisomy 21) is the most common chromosomal abnormality and people with Down syndrome have varying degrees of mental retardation and physical birth defects.

In 2007, the American College of Obstetrics and Gynecology (ACOG) recommended that all pregnant women, regardless of age, be offered screening for Down syndrome, as well as the option of diagnostic testing.  Diagnostic testing can tell with greater than 99% accuracy whether or not a pregnancy is affected with Down syndrome, Trisomy 18 and other chromosomal abnormalities, as well as certain genetic diseases (if indicated).

The decision to have genetic testing is highly personal and a genetic counselor may help a couple make an informed decision about whether or not to pursue genetic testing.

Family History of Genetic Disorder (or Conditions Associated with a Genetic Disorder)

Your family health history is one of the most important tools in assessing the risk to have a child with a birth defect and/or genetic disorder. A genetic counselor will ask questions about your family health history including your reproductive history, major health conditions, known genetic disorders, age of disease diagnosis, lifestyle factors and ethnicity.

Inherited Health’s Family Health History tool allows couples to securely input their family health history online and obtain a personalized assessment of the risks to their pregnancy. Risk assessment is also possible before a couple is even pregnant. By understanding your risks, you can make more informed healthcare decisions with your provider and be a better advocate for your baby’s health.

There are a number of reasons why your pediatrician may recommend that your child meet with a medical geneticist, a doctor who specializes in the diagnosis and management of genetic diseases and syndromes. Some of these reasons include:

• Abnormal results on newborn screening
• Growth abnormalities
• Physical abnormalities or malformations (such as heart defects, spina bifida, etc.)
• Mental retardation or development delay
• Autism
• Seizures and epilepsy
• Evaluation for a suspected genetic condition or chromosome abnormality
• Blindness or deafness
• Family history of a known or suspected genetic condition, congenital birth defect, or chromosome abnormality

Genetic consultations take on average 60 minutes. Pediatric consults may require multiple visits over time as different features may become apparent at specific ages or developmental stages.

In addition to the medical geneticist, a genetic counselor may also participate in the consultation. Genetic counselors are specialists trained in both medical genetics and counseling.

At the appointment, the doctor or counselor will begin by taking a detailed personal and family health history by creating a family health tree called a “pedigree.” The doctor may also perform a physical exam. All of the information gathered in the consultation will be evaluated along with any other relevant genetic and non-genetic test results to:

• Assess genetic risks
• Diagnose, confirm, or rule out a suspected genetic condition
• Discuss diagnostic genetic testing options
• Discuss condition management or treatment.

Before a genetic consultation, it is helpful to collect your family health information from relatives including disease diagnoses, age of disease onset or death, genetic testing results, as well as non-genetic, medical testing results.

Inherited Health’s Family Health History tool allows you to collect, document and update your family health history online so it can be conveniently printed before any doctor’s appointment.  When you better prepare for your appointment, you can be a better advocate for your child.

Every year it seems like more and more genetic tests are offered during pregnancy. Due to a recent recommendation made by the American College of Medical Genetics (ACMG), the latest carrier test to be offered by OB/GYNs and genetic specialists is for spinal muscular atrophy (SMA).

What is SMA?

The number 1 inherited cause of childhood death, spinal muscular atrophy is a group of devastating genetic disorders that affect muscle movement and cause muscle degeneration and weakness. SMA is divided into types (SMA Type 0 – SMA Type IV) based on symptom severity and the age of symptom onset.

How is SMA inherited?

SMA has autosomal recessive inheritance, which means that two alterations, one in each gene copy, are necessary to cause the disorder. People with only one mutated copy are called carriers. Two carriers have a 25% chance to have an affected child, but do not typically have symptoms themselves. As such, carriers of SMA may not know they have a mutation until they have an affected child.

What is your chance to have an affected child?

A family history of SMA can significantly increase your chance to be a carrier.

For example, if you have a sibling who is a carrier of SMA, you have a 50% chance to also be a carrier. If you have a first cousin who is affected with SMA, you have a 25% chance to be a carrier.  If you have a child with SMA, you and your partner have a 100% chance to both be carriers, and a 25% chance to have another affected child.

Even if you have NO family history of SMA, you can still be a carrier.

In the absence of a family history, the risk of being a carrier is based on your ethnic background, as SMA is more common in people of certain ethnic backgrounds.

Understanding your risk is the first step to making an informed decision about carrier testing. To better understand your personal risk, you can use our Family Health History tool to assess the risk for SMA in addition to over 200 other hereditary diseases.

Making a family tree can be much more than just an interesting hobby.  You can create a “healthful” legacy for your children by adding information about the diseases that have occurred in your family – turning your family tree into a family health tree.

Your family health history can help identify the hereditary diseases you are more likely to develop and pass down to your children. It can even be life-saving.

When you document your family health history, you can share it with your doctor and child’s pediatrician who may use it to:

• Assess your risk of certain diseases
• Assess the risk to your relatives including your children
• Diagnosis a health condition
• Recommend more effective treatments
• Recommend lifestyle changes to help lower your disease risk
• Recommend preventative measures
• Determine which clinical, screening or genetic tests to consider
• Determine how frequently to screen and monitor for disease
• Refer you to a genetic specialist for further consultation

A family health history is only as helpful as it is accurate. This means that you may have to ask your relatives to fill in missing information. Once you have collected your family health history, make sure to update it when any major changes occur including diseases diagnoses, births, miscarriages and deaths.

An innovative alternative to pen and paper, Inherited Health’s Family Health History tool allows families to archive their history together in a secure online fashion. The inputted information is then analyzed to produce a Personal Health Guide, which identifies hereditary disease risks and ways to lower these risks. Families can privately share their health information amongst themselves or print their Personal Health Guide for their doctor.

Armed with this knowledge, we can all take steps to improve our health and that of our loved ones.

Back in 1995, a man died tragically when he was only 42 years old. The official diagnosis was liver failure from alcoholic cirrhosis. No autopsy was done. The body was cremated. No clues remained. End of story. Or was it?

The July 7, 2001 issue of The Lancet chronicles a story of deductive reasoning, genetic medicine, and international cooperation. A physician relative of the deceased kept wondering if the death might have been not due to alcohol but instead from a rare genetic disorder.

The only remaining clue was tiny bits of his skin left in an old electric shaver. These were sent to Semmelweis University in Budapest, Hungary. The genes were analyzed by means of polymerase chain reaction (PCR) amplification in the US.

The result?

The unfortunate man was found to have undiagnosed Wilson disease. This rare genetic condition causes the relentless build-up of copper in the liver, leading to liver failure and brain damage. Effective treatments are available, but Wilson disease is fatal if untreated.

The family learned that alcoholic cirrhosis was not the cause of death. They also learned that his two children (and his father) are carriers of the rare recessive condition. What powerful information was gleaned from nearly-forgotten traces of DNA in that old electric shaver!

If you save a precious lock of your child’s hair, or those tiny baby teeth, or the remnants of her umbilical cord, your memento may prove to have more than just sentimental value as we move through the 21st century.

Dr. Greene’s Answer:

Having a baby is a lifelong responsibility and hopefully an even greater reward — for somebody! As a mother’s belly swells, she knows with deep certainty that the child is hers. Each time the baby moves or kicks, the bond between her and her child grows.

Depending on the situation, the father may be pretty sure that the child is his. For most of history, though, dads have had to rely on circumstantial evidence as the foundation on which to build this crucial relationship. After the baby was born, he could feel more sure he was the dad if the baby looked like him (“He has your feet, Honey!”), but often these early resemblances are at least partially creative imaginations.

In 1901 biologist Karl Landsteiner distinguished between three types of blood — groups A, B, and O. A fourth group — AB — was discovered a year later by another research team. As the inheritance patterns of these blood groups were worked out over the next decades, it became possible to use blood tests to exclude some men from being the fathers of some children. For instance, if the parents both have blood type O, then the children must all have blood type O. If a child were to have blood type A, B, or AB, then the presumed father must not be the real father. If the child’s blood type were O, then the presumed father might be the real father — but so might millions of other men. Here is a list of possible and impossible situations:

These are general rules, though, and exceptions apply. Very rarely, gene mutations may change the rules such that “impossible children” become possible. The geneticists at Stanford wrote a great explanation to this on the website for The Tech Museum of Innovation, at www.thetech.org/genetics/ask.php?id=181.

Today there are over 600 blood types known (as well as other tissue types called HLA types), which can make paternity testing far more accurate — but still not perfect.

It is also now possible to determine the father before a baby is born. This is done by comparing DNA molecules — our genetic blueprints. To do this you need a blood sample from both the mother and the potential father (testing without the mother’s blood is possible, but more difficult — and more expensive). You also need a small sample of amniotic fluid (the water that the baby is floating in). Less than 1/4 teaspoon is sufficient for the test. The amniotic fluid may be obtained by a process called amniocentesis. This procedure is performed no earlier than 13 weeks into the pregnancy.

A court order or informed consent of all adults involved is required to proceed with paternity testing.

You will need to wait 3 to 4 long weeks for the results. Waiting for these test results can be a very anxious time. Rush orders take 10 to 15 business days, but cost about $500 extra.

Either way, if the test says that a man is not the father, then legally and truly he is not (it can absolutely exclude some men as the father of a certain child). If the test says that he is the father, then he probably is — there is about a 99.8% chance that he is. DNA testing is now legally accepted as able to determine paternity.

There are about one million two hundred eighteen thousand five hundred males in Jamaica (as of 1992). A positive DNA paternity test could limit the potential fathers to only about 2,437 of them (plus 0.2% of the tourists). Only 2 out of 1000 men could possibly be the father. As you can see, a positive paternity test is good evidence, but not an ironclad guarantee.

Prenatal paternity testing can be arranged through a company called Genelex, located in Seattle, Washington. They are very helpful, and can be reached at 1.800.523.6487 or www.healthanddna.com/. The test costs $700.

If you wait until after the baby is born, DNA testing can be arranged through most local blood banks (many of which use Genelex). The blood sample can be obtained at birth. Otherwise, the baby should be at least 2 months old, since a fair amount of blood is needed for the test. In my area, this option costs about $600.

I realize that the circumstances that prompt a person to undergo paternity testing are often difficult. I hope that whatever you want turns out to be true. Even more, I hope that whatever turns out to be true becomes something that you learn to want.

Dr. Greene’s Answer:

Melissa, quite a lot has happened since I wrote you last week. On Wednesday, I drove about an hour and a half to Santa Rosa, California to be present when my sister had a baby. She had had a dream pregnancy, but the baby was in a breech position. A cesarean section was scheduled for 7:45 Wednesday morning, and I was able to schedule to be there — as her brother, not her pediatrician.

As I was driving, Melissa, I remembered your sorrow. I hoped that another child would be able to have you as a mother. I reflected on what a miracle it is whenever a healthy baby is born. Pregnancy and gestation are so complex. Human life is so fragile and strong and beautiful. What a privilege to see a baby come into the world.

When I arrived at the hospital, three generations of Greene’s were gathered, tingling with excitement at the magic that was about to happen. We filled the waiting room. My sister and her husband had decided on Brandon Alan if he were a boy, and Brooke Michelle if she were a girl.

When the time came, I went into the operating room with my sister (along with her husband and parents). My job was the video camera, to record memories of one of life’s greatest moments.

Through the lens, I saw her perfect legs and bottom first. “It’s a Brooke Michelle, and she’s beautiful!” I announced. “Congratulations!!!”

Then the obstetrician cautioned, “She has a little cleft lip.” I saw my father’s face fall, and felt a chill in my own heart. Suddenly the moment didn’t seem perfect. I knew that modern cleft lip repair has spectacular results, but it felt as if a bubble had burst.

I rushed to the warming bed where the pediatrician was giving baby Brooke Michelle some oxygen. Was this some kind of nightmare? It looked as if she had trisomy 13!

Arrangements were made to transport Brooke to a university medical center. My sister (as is the standard practice when babies are transported) was left behind, a hollow loneliness replacing a lifetime of hopes and dreams.

As a side note, this practice of separating sick babies from their mothers is wrong. I can understand why insurance companies say that co-transporting the mothers “is not a covered benefit,” but my goal is to overturn this accepted barbarism. In my sister’s case, with much effort we were able to get her transferred an interminable day later. But back to more immediate concerns…

Within hours, the diagnosis was confirmed — trisomy 13. Dreams of her first tentative steps, her first spoken “Mama,” her playing happily in a park, her entire future, all vanished. This was a nightmare from which we would not wake up.

Less than a week ago, I wrote about a mom rocking her baby, knowing that he would die. Today I was in the rocking chair, holding my precious niece. She sucked on my little finger in rhythm with our rocking, cuddling in close. It was a moment that seemed at once endless and slipping away all too fast. The fullness of love and sorrow suffused my heart, and once again I knew that I would never be the same.

Looking at Brooke’s misshapen face, I recalled that all babies’ faces looked like hers early in development. It’s just that most continue to grow and change, and hers didn’t.

My children were introduced to Brooke that first evening, one at a time. Each one’s genuine response was, “She’s beautiful!” I love how they could see her preciousness and not be distracted by her looking different from other babies.

I drove back to see my sister later that first night, and along with everything else, I could see a searching guilt in her eyes. What had she done to make this happen? Was it something she had eaten? A virus she had? Was it the time that she had fainted?

No. No. No. Trisomy 13 is an extra copy of the 13th chromosome that slips in at the moment when the sperm and egg join. Nothing that happens later can change that unalterable fact. Most embryos with trisomy 13 do not survive to be born. Most who are born have mothers, like my sister, who took exquisite care of themselves — not who did something wrong.

Melissa, I am thrilled that your chromosome tests came back normal. This indicates that Quinten’s translocation began with him, a spontaneous event at conception. I do recommend meeting with a geneticist to go over together as much as is known about your family history. The geneticist should be able to give you the risk of recurrence for your specific situation. In all likelihood, the risk of having another baby with trisomy 13 will be extremely low. No other pre-conception testing is available, or necessary. After conception, you can know for certain by 16 weeks, using a combination of ultrasound, CVS, and/or amniocentesis.

When I wrote you last week, I wanted to say something about how trisomy 13 children live on after they die in the way that they change those who love them — but I didn’t want to sound trite, or minimize your loss. Today, though, I’m not afraid to say it. Brooke Michelle and Quinten Gabriel will have a legacy that will ripple through generations to come. Those precious, brief lives have changed us with their searing intensity. I have always loved my sister, but today I love her with a fierceness and tenderness that aches sweetly in my marrow. I feel joined to my brother-in-law as never before. The borders of my heart have been stretched a little wider, to take in more of the beauty and tragedy that surrounds us all. None of us will ever be the same.

Let Quinten Gabriel’s life deepen your capacity for joy and for pain. Let it open you and connect you and make you willing to risk. And thank you, Melissa, for the uncanny way that you and Quinten Gabriel helped prepare me and my family for our little treasure.

N.B. A special fund has been set up in Brooke Michelle’s memory. Contributions can be made to the Brooke Michelle Fund for the Prevention of Birth Defects. This charity will be administered by the University of California San Francisco and will help fund medical research. Checks should be made out to: UC Regents–Brooke Michelle Fund. Mail should be addressed to the Brooke Michelle Fund, c/o Dr. Karin Vargervik, University of California San Francisco, 521 Parnassus Avenue, San Francisco, CA 94143-0442.

Dr. Greene’s Answer:

Melissa, one of my most vivid memories from my pediatric residency was sitting with a mom while she rocked her son who was born with trisomy 13. We were in the Intensive Care Nursery at Children’s Hospital Oakland, surrounded by tiny premature babies in incubators. This boy was full term and normal size. While the other babies were all hooked up to mechanical ventilators, IV pumps, or other high tech equipment, this child was simply wrapped in a receiving blanket, cradled in his mother’s arms. As she gently rocked back and forth in the plain wooden chair, she knew that he would die within a day.

The fullness of motherhood was compressed into that day. A mother’s deep love for her son, her tender concern, her exquisite pain of separation, her comforting touch for a lifetime’s scraped knees, her worry for a lifetime’s dangers, her peace in their inseparable bond, all came together in that rich moment as she gazed upon her precious little boy.

Even when our children have normal life-spans, their childhoods vanish oh so quickly. When childhood is cut short, it is a gut-wrenching shock. Trisomy 13 (also called Patau Syndrome) occurs in up to 1 out of 5,000 newborns (Smith’s Recognizable Patterns of Human Malformation, Saunders 1988). Even the mildest forms of this syndrome can be devastating.

The 13th chromosome contains blueprints that direct a baby’s development in the early weeks following conception. When a child has an extra 13th chromosome (three copies, instead of two), as is the case in trisomy 13, the genetic messages are confused and contradictory – there’s just too much to juggle. This results in multiple significant defects in major organ systems. The brain is often the most severely affected. Children with trisomy 13 may also have abnormalities in the shape of their lips, eyes, ears, fingers, toes, and bones. It’s also common for these children to be born blind, deaf, and with no sense of smell. Taste and touch become the limited means by which a mother can convey an ocean of feeling.

Most children with trisomy 13 have some kind of heart defect, but a double-outlet right ventricle is not common. A normal heart has four chambers. Blood from the body enters the right atrium. From there, it flows into the right ventricle, whose strong muscular wall sends the blood out of the heart to the lungs (via the pulmonary artery). In the lungs, the blood is supplied with oxygen before it returns to the heart, entering the left atrium. From there, it flows into the left ventricle, whose mighty walls propel the blood out of the heart (via the aorta) to supply the rest of the body with oxygen.

In double-outlet right ventricle, the pulmonary artery and aorta both exit from the right ventricle. Thus, poorly oxygenated blood is used for the body’s main supply. The only exit from the left ventricle is a hole in the wall (called a ventricular septal defect) through which the oxygenated blood from the lungs can at least enter the right ventricle to blend with the depleted blood from the body before it leaves. In your son, a hole in the wall between the two atria (an atrial septal defect) also allowed mixing of the blood entering the heart. Double-outlet right ventricle occurs in less than 1 percent of children with congenital heart disease.

Trisomy 13 was first described in 1657, but four hundred fifty years of medical knowledge have not improved the outlook for children born with this syndrome. Most babies who are conceived with trisomy 13 die early in gestation. Of the babies who live to be born, about 44% die within the first month and 69% die by six months. Only 18 percent reach their first birthdays — and these have severe mental defects and seizures (Smith’s Recognizable Patterns of Human Malformation, Saunders 1988).

While we cannot cure trisomy 13, we have started to find ways to detect it early. Sometimes, a blood test, called the AFP (alphafetoprotein) or triple screen, may help a pregnant woman find out her baby’s risk of several diseases, including Trisomy 13. Trisomy 13 is often detectable on prenatal ultrasound as early as 10 weeks of pregnancy. Chorionic villous sampling can detect trisomy 13 by 12 weeks. Amniocentesis, usually performed after 16 weeks gestation, can give a definite answer if any question still remains.

Often, trisomy 13 is associated with older mothers. Even so, the risk of having another baby with trisomy 13 is usually very low — unless, as with your son, the trisomy 13 is a translocation. A translocation is not associated with mom’s age, but is a hereditary chromosome problem. The risk of recurrence in some types of (balanced) translocations can be quite high. The inheritance of trisomy 13 is very complex. By testing your blood and that of the baby’s father, a geneticist can give you the best available information for your situation.

Trisomy 13 is a desolate and difficult challenge that I wish you didn’t have to face. Melissa, your mother’s heart comes through in your search for information about your son. You are a mother in the fullest sense of the word.