Genetics Northern California


Cafe Au Lait SpotA flat, milky-brown, pigmented spot found on the skin.
Canavan Disease

An autosomal recessive disorder in which there is progressive deterioration of the central nervous system (brain).


A condition that involves the uncontrolled and abnormal division of eukaryotic cells. An informal term for a diverse class of diseases marked by uncontrolled cellular growth.


The production of cancerous growths.


Cancers occurring in the epithelial cells covering the surface of the body and lining the internal organs. Carcinomas account for about 90% of all cancer.

CardiologistA medical doctor who specializes in heart problems.
CarrierAn individual who carries the abnormal gene for a specific condition (often, a recessive condition) without symptoms.
Caudal AgenesisThis term is used synonymously with sacral agenesis, since in most cases only the sacrum is involved. It is a loosely defined syndrome of vertebral malformations, ranging in severity from agenesis of the coccyx to absence of the sacral, lumbar, and even lower thoracic vertebrae. With high sacral and above malformations, there may be significant neurological deficits, as well as anomalies involving the genitourinary tract, intestines, and the respiratory system.

A small, watery, membrane-bound compartment filled with chemicals; the basic subunit of any living thing.

Cell Cycle

The cycle of cell growth, replication of the genetic material, and nuclear and cytoplasmic division.

ChelationProcess of using an agent to inactivate a toxic substance.
CholesterolThe most abundant steroid in animal tissues, present in foods rich in animal fats. A type of fat in every cell of the body necessary for the production of sex hormone, vitamin D, bile, skin oils, and protective nerve coverings, and it is a component for the building block of a cells. Cholesterol is only found in animals, not plants. Deposits of cholesterol form in the arteries, eventually leading to blockage.
Chorionic Villus Sampling

A procedure used for prenatal diagnosis in which a sample of the placenta, specifically the villous area of the chorion, is withdrawn either transabdominally or transcervically.

Choroid plexusThe part of the brain that produces cerebrospinal fluid.
Choroid plexus cyst

A pocket of fluid that collects in the choroid plexus of the brain. Benign in itself, the presence of a choroid plexus cyst in utero has been associated with an increased risk for Trisomy 18.

Chromosome(s)Structures found in the nucleus of a cell which contain the genes. Chromosomes occur in pairs and a normal human cell contains 46 chromosomes, 22 pairs of autosomes and two sex chromosomes.
Cleft Lip

An incomplete closure of the top lip resulting in a separation or 'split' within the lip. This can be limited to one side (unilateral) or can occur on both sides (bilateral). Cleft lips can occur in isolation, with cleft palate, and/or as part of a syndrome.

Cleft Palate

An incomplete closure of the top or "roof" of the mouth. This can occur in isolation, with a cleft lip, and/or as part of a syndrome.

Clinical Heterogeneity

The production of clinically different phenotypes from mutations in the same gene.


A group of genetically identical cells or organisms that are descended from one parent. In molecular biology,. a copy of DNA sequences created by recombinant DNA techniques.

Club Foot

A congenitally deformed foot which is twisted out of shape or position.


A triplet of three bases in a DNA or RNA molecule specifying a single amino acid.


The onset of pregnancy marked by fertilization of the egg by the sperm.

Confined Placental Mosaicism

Mosaicism that is seen in the placenta but not the fetus.


Present at birth; not necessarily genetic.

Congenital Adrenal Hyperplasia (CAH)

The adrenal glands of babies with this disease do not make enough of the key stress-fighting hormone cortisol.  In about two-thirds of the cases, babies also do not produce enough of the salt-retaining hormone aldosterone. As a result, affected babies can develop dehydration, shock, and even death. Treatment with one or more oral medicines can help prevent these problems. Girls with this disorder may have the additional problem of having masculine-looking external genitals, which can be corrected with surgery.

Congenital Heart Defect

Abnormal development of the heart or of the blood vessels near the heart that is present at birth.


Relationship by descent from a common ancestor (blood relationship).

Constant SpringHemoglobin variant that are phenotypically similar too alpha thal trait. Point mutation causes decrease in the amount of alpha chains produced.
ConsultIndividual requesting genetic counseling.

Individual requesting genetic counseling.

Contiguous gene syndrome

Genes physically close on a chromosome that express a phenotype when acting together.

Coronary artery diseaseHeart disease that develops due to a deposition of fat in the coronary arteries of the heart. If the coronary artery becomes blocked, a heart attack occurs.
Corpus callosumAn arched mass of white matter found on the longitudinal fissure. It connects the cerebral hemispheres of the brain with transverse fibers.

Pertaining to the cranium(upper part of the head) and the face.


Premature closure of the sutures of the skull which can result in deformities.


Chorionic Villus Sampling.

Cystic FibrosisAn autosomal recessive genetic condition of the exocrine glands which causes the body to produce excessively thick, sticky mucous that clogs the lungs and pancreas interfering with breathing and digestion.