Genetic Disorders

Genetic disorders is a category of diseases that includes certain types of birth defects, chronic diseases, developmental problems, and sensory deficits that are inherited from one or both parents.

Birth defects

• Cataracts
• Cleft lip or palate
• Congenital heart disease
• Contractures
• Diaphragmatic hernia
• Genital malformations
• Glaucoma
• Misshapen skull
• Missing fingers or toes
• Missing or incomplete arms or legs
• Spina bifida or open spine defects

Chronic diseases

• Bleeding disorders
• Childhood cancers
• Kidney or urinary tract disease
• Slow growth or short stature
• Cystic fibrosis
• Sickle cell disease
• Thalassemia

Developmental problems

• Autism spectrum disorders
• Attention deficit/hyperactivity
• Developmental delay
• Failure to thrive
• Learning disability
• Loss of developmental skills
• Low muscle tone
• Mental illness
• Mental retardation
• Speech problems
• Seizures

Sensory deficits

• Extreme farsightedness
• Extreme nearsightedness
• Hearing loss
• Retinal or other visual problems

Some of the symptoms can be the same as those for conditions that are not inherited. Features can appear at birth (congenital heart disease, or cleft lip or palate) or during the course of childhood (developmental delays or learning problems). Diagnosis may involve a physical exam or targeted genetic testing.

The following list includes features that might suggest that your child has a genetic disorder. However, some of these characteristics are commonly found in people without a disorder. You'll want to check with your doctor if your child has at least two of the following features:

• Ear abnormalities
• Unusually shaped eyes
• Different colored eyes
• Facial features that are unusual or different from other family members
• Brittle or sparse hair
• Excessive body hair
• White patches of hair
• Large or small tongue
• Misshapen teeth
• Missing or extra teeth
• Loose or stiff joints
• Unusually tall or short stature
• Webbed fingers or toes
• Excessive skin
• Unusual birthmarks
• Increased or decreased sweating
• Unusual body odor

Genetic counseling can tell you whether you're at risk of developing a genetic disorder or having a child with a genetic disorder. Genetic counseling can also help you to make sense of the information and put it into context for your child. It may be conducted by a geneticist, a doctor with special training, or a genetic counselor, who will explain the cause of a disorder, availability of testing, prognosis, medical management, and treatment. Genetic counseling sessions typically last an hour or longer, depending on the complexity of your child's case is. There are many reasons to seek genetic counseling, including the following:

1. Family history or previous child with:

• Chromosome abnormalities (such as Down syndrome)
• Cleft lip/palate
• Heart defects
• Mental retardation
• Neural tube defects
• Short stature
• Single gene defects (such as cystic fibrosis or PKU)
• Hearing or visual impairments
• Learning disabilities
• Psychiatric disorders
• Cancers
• Multiple pregnancy losses (miscarriages, stillbirths, or infant deaths)

2. A parent with an autosomal dominant disorder, or any disorder seen in several generations

3. Pregnancy factors (mother older than 35 years)

4. Mother with any of the following:

• Schizophrenia
• Depression
• Seizures
• Alcoholism
• Diabetes
• Thyroid disorder
• Fetal or parental exposure to certain drugs, chemicals, radiation, or infections
• Advanced paternal age at the time of conception
• Infertility cases where either parent is suspected of having a chromosome abnormality
• Couples requiring assisted reproductive techniques to achieve a pregnancy, or individuals donating eggs or sperm for those purposes
• Ethnic groups or geographic areas with a higher incidence of certain disorders, such as Tay-Sachs disease, sickle cell disease, or thalassemia

Boston Children's provides genetic testing for pregnant women, newborns, and children of all ages. In some cases, a diagnosis can be made after a physical exam. Most of the time, genetic disorders are diagnosed through a specific test, which can include examining chromosomes or DNA (the tiny proteins that make up genes), or testing the blood for certain enzymes that may be abnormal. Studying enzymes is called biochemical genetic testing.

At your initial appointment, a member of the genetics team (a genetic counselor, a clinical genetics fellow, and/or a geneticist) will review your medical, family, and pregnancy history and perform tests. Tests may include X-rays, an MRI, or genetic tests (usually blood or urine tests). Your child may also be referred to a specialty clinic within the hospital.

The different categories of genetic tests are:

• Predictive genetic testing can tell you the chances that a healthy person with or without a family history of a certain disease might develop that disease. These diseases can include some types of cancer and heart disease.
• Presymptomatic genetic testing can tell if a person with a family history for a genetic disease but does not have symptoms or has a genetic alteration associated with the disease.
• Carrier testing can determine if a person carries one copy of a gene linked to a certain disease. An "autosomal recessive" disease means that the disease will appear only if two copies of the altered gene are inherited. Couples who both carry the same autosomal recessive gene have a one in four, or 25 percent, chance with each pregnancy to have a child with that disease.
• Prenatal diagnosis is used to diagnose a genetic disease or condition in the developing fetus. Prenatal tests include screening blood, ultrasound (sonograms), amniocentesis, chorionic villus sampling (CVS), and percutaneous umbilical blood sampling (PUBS).
• Preimplantation studies are used only in in vitro fertilization to diagnose a genetic disease in an embryo before it is implanted into the mother's uterus.
• Newborn screening is used to check for certain genetic disorders that can be diagnosed and treated early in life.

The Division of Genetics and Genomics works closely with the Genetics Division's research laboratories to develop scientific findings into new treatments and cures for your child. Home to the world's only center studying rare “orphan” diseases that affect fewer than 200,000 people in the country, we are poised to become the richest database of genetic and clinical pediatric data in the world.