Genetics Northern California



Lobular carcinoma in situ. Abnormal cells within the lobule which don't form lumps. They can serve as a marker for future breast cancer risk.

LDLLow density lipoprotein or the "bad cholesterol" is the cholesterol that causes the cholesterol or fatty plaques to build in the walls of an individual's arteries.

Large for gestational age.

Limited dorsal myeloschisis

A defect of primary neurulation resulting from incomplete fusion of the posterior neural tube. A slender stalk of neural tissue extends through the nuchal fascia into the myelomeningocele sac.


The occurrence of different genes on the same chromosome that are usually inherited together.

Lipid1) Any of a heterogeneous group of fats and fat-like substances. In the body, serve as a source of fuel (Dorland's). 2) Fats, which are any of a group of organic substances that are insoluable in water, but soluable in alcohol. They are easily stored in the body and are important for cell structure.
Lipid panelThis is a series of four fats being measured in the blood stream (in a fasting state of 10-12 hours) and are as follow: total cholesterol, LDL, HDL, and triglyceride.
Lipomyelomeningocele, lipomeningocele

A spinal cord lipoma associated with an underlying spina bifida lesion. Often, the fatty tissue of the lipoma extends into the spinal canal, and may press on the spinal cord, resulting in progressive neurological deterioration.

Lisch nodulesAreas of pigment accumulation in the colored part of the eye (iris). Also known as "iris nevi", Lisch nodules do not affect vision.
Liver function tests (LFT)These tests are done to check the functioning of the liver. They are usually done before any lipid-lowering drug is given and then again, every so often, once lipid-lowering drugs are given to make sure liver function is not impaired by the medication (i.e., AST (SGOT) and ALT (SGPT).)
LMP (Last Menstrual Period)

First day of LMP is date used to determine the gestational age of the fetus and predict date of delivery.


The position or place on a chromosome occupied by a particular gene or one of its alleles.

LOD score

A statistical estimate of whether two loci are likely to lie near each other on a chromosome and therefore are likely to be inherited together. A LOD score of 3 or more is generally taken to indicate that the two loci are linked when using standard linkage techniques. 

Low mean corpuscular volume (MCV)First and only clue to the presence of thalassemia. (Normal range of MCV is 79-102). Nine out of 10 patients with low MCV will have iron deficiency anemia. MCV does not begin to decrease until deficiency is significant. If patient also has elevated Hgb A2, confirms beta thal minor.
Lp(a)Lipoprotein little (a) is a subset of fats that, if elevated (usually over 100), are felt to be another risk factor for developing early coronary artery disease or strokes.