Genetics Northern California

Glossary

TermDescription
Sacral agenesis

This term is used synonymously with caudal agenesis. 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.

Saturated fatsThese fats are solid at room temperature and are animal in origin, except for palm and coconut oils. These fats tend to increase blood cholesterol levels.
Scoliosis

A significant lateral deviation in the normally straight vertical line of the spine.

Screening

A mass examination of the population to detect the probability of a particular disease (ie. Ex-Afp to look for Down Syndrome and openings in the brain and spine).

Secondary cancerCancer that has metastasized to a different location than the initial organ where the cancer was identified (ie. Breast cancer seen in brain and lung tissue).
SequenceA primary defect with secondary structural changes in development (e.g. Pierre-Robin sequence).
SequencingThe act of determining the amino acid pattern at a given gene location in an individual.
Sex chromosomesChromosomes responsible for sex determination. In humans it is XX in female and XY in males.
SGA

Small for gestational age-the child is born smaller than expected for their age (usually describing smaller than the third percentile) for that gestational age.

Short statureSmaller in height than expected for chronological age.
Sickle cell disease (sickle cell anemia)An autosomal recessive genetic condition where the hemoglobin protein is mutated giving red blood cells a sickle shape that can block circulation. This condition causes lifelong anemia and other chronic problems and is found mostly in individuals of African or Mediterranean origin.
Skeletal dysplasia

A change in the development or structure of the bones and/or connective tissue giving rise to a genetic condition (ie. dwarfing syndromes).

Skeletal muscleOne of three types of muscle tissue in the body (skeletal, smooth, cardiac) which represents the majority of the muscular tissue in the body. Skeletal muscle is the type of muscle which powers movement of the skeleton as in walking and lifting.
Soluable fiberThis fiber is able to be absorbed by the body and is found in citrus fruit, dried peas and beans, oats, and barley. It is felt to help lower blood cholesterol and sugar levels.
Sonogram

The use of sound waves to visualize soft tissue organs and human fetuses (same as ultrasound).

Southern blot

A technique for transferring DNA segments from an agarose gel to filter paper and which is then probed with radioactivity to see if a particular change or mutation is present in an individual.

SpherocytosisCondition in which erythrocytes assume a spheroid shape. Occurs in certain hemolytic anemias.
Spina bifidaA condition that results from altered fetal development of the spinal cord causing the individual to usually have hydrocephalus, bowel and bladder dysfunction and spotty sensation to no sensation in the lower extremities. Folic acid felt to help lower incidence of this birth defect if taken by mothers during the first trimester and a month prior to conception.
Spina bifida occultaLiterally “hidden” spina bifida. Most often involves a bony defect of the spinal column only and is discovered incidentally during a routine x-ray. Sometimes accompanied by external signs, such as a tuft of hair or discolored area on the back. Some forms of spina bifida occulta may involve the spinal cord, and require surgery (such as release of tethered spinal cord). Such as lipomyelomeningocele, lipomeningocele, split cord malformations, thickened or fatty filum terminale, and some dermal sinus tracts.
Spinal cord lipomaA collection of fatty tissue attached to the spinal cord that may or may not be associated with spina bifida. There are three types of lipomas: dorsal, transitional, and terminal. Dorsal and transitional lipomas are defects of primary neurulation, and may be associated with spina bifida. Terminal lipomas are considered secondary neurulation defects.
SplenomegalyEnlargement of the spleen with hemolytic diseases of the blood.
Split cord malformation (diastematomyelia, diplomyelia)

The spinal cord (the bundle of nerves found in the spine) is split in two, usually by a piece of bone or cartilage. Split cord malformation (SCM) does not occur in isolation and is always connected with other abnormalities of the spine, particularly tethered cord. It can present as a simple splitting of the cord housed in a single dural sac with a nonrigid median septum (Type II SCM) or as double dural sacs with an osseous or osseocartilaginous midline septum (Type I SCM). It occurs more commonly in females than males, and mostly in the lumbar or lower thoracic region.

Spondylometaphyseal dysplasias

These conditions primarily affect the spine and the metaphyses (growing portion of the bone) of the long bones. Diagnosis is usually made between ages 2-3 and individuals have mild to moderate short stature with a short trunk and a waddling gait. The two main types, Kozlowski and Sutcliffe (also formerly called Corner Fracture Type), can be distinguished by x-ray findings in the spine.

Spondylothoracic dysplasiaThis condition is also known as Jarcho-Levin and is characterized by a short trunk (body) and multiple vertebral and rib abnormalities. Short stature is mild-moderate as the arms and legs are not significantly affected. Potential problems include: respiratory insufficiency and spine abnormalities which may cause limited neck motion or, more seriously, compression of the spinal cord
Sporadic mutationThe first mutation or occurrence of disease in a family with no apparent genetic transmission pattern.
Syndactyly

Fusion of fingers or toes to each other.

SyndromeA characteristic overall pattern of features or birth defects believed to be caused by a single underlying event.