Lipid storage disorders are a group of inherited metabolic

Metabolism

Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 disorders in which harmful amounts of lipid

Lipid

Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...

s (fats) accumulate in some of the body’s cells

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 and tissues. People with these disorders either do not produce enough of one of the enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

s needed to metabolize lipids or they produce enzymes that do not work properly. Over time, this excessive storage of fats can cause permanent cellular and tissue damage, particularly in the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

, peripheral nervous system

Peripheral nervous system

The peripheral nervous system consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system to the limbs and organs. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain...

, liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

, spleen

Spleen

The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...

 and bone marrow

Bone marrow

Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...

.

Lipid

Lipid

Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...

s are broadly defined as any fat-soluble (lipophilic), naturally occurring molecule, such as fats, oils, waxes, steroids (such as cholesterol

Cholesterol

Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

 and estrogen

Estrogen

Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...

), sterol

Sterol

Sterols, also known as steroid alcohols, are a subgroup of the steroids and an important class of organic molecules. They occur naturally in plants, animals, and fungi, with the most familiar type of animal sterol being cholesterol...

s and others. Lipids are important parts of the membranes found within and between each cell and in the myelin sheath that coats and protects the nerve

Nerve

A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...

s.

Inside the cells, lysosome

Lysosome

thumb|350px|Schematic of typical animal cell, showing subcellular components. [[Organelle]]s: [[nucleoli]] [[cell nucleus|nucleus]] [[ribosomes]] [[vesicle |vesicle]] rough [[endoplasmic reticulum]]...

s convert, or metabolize, lipids and proteins into smaller components to provide energy for the body. Disorders that store this intracellular

Intracellular

Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...

 material are part of the lysosomal storage diseases family of disorders and include GM1 gangliosidoses

GM1 gangliosidoses

The GM1 gangliosidoses are caused by a deficiency of beta-galactosidase, with resulting abnormal storage of acidic lipid materials in cells of the central and peripheral nervous systems, but particularly in the nerve cells.-Early infantile GM1:...

, GM2 gangliosidoses

GM2 gangliosidoses

The GM2 gangliosidoses are a group of related genetic disorders that result from a deficiency of the enzyme beta-hexosaminidase. This enzyme catalyzes the biodegradation of fatty acid derivatives known as gangliosides. The diseases are better known by their individual names.Beta-hexosaminidase is a...

, Gaucher disease, Niemann-Pick disease

Niemann-Pick disease

Niemann–Pick disease refers to a group of fatal inherited metabolic disorders that are included in the larger family of lysosomal storage diseases .-Signs and symptoms:Symptoms are related to the organs in which they accumulate...

, Fabry disease, fucosidosis

Fucosidosis

Fucosidosis, also called alpha-l-fucosidase deficiency, is a rare autosomal recessive lysosomal storage disease in which the enzyme fucosidase is not properly used in the cells to break down fucose. This enzyme normally cleaves long sugar chains known as oligosaccharides in the lysosome...

, Schindler disease

Schindler disease

Schindler disease, also known as Kanzaki disease and Alpha-N-acetylgalactosaminidase deficiency is a rare congenital metabolic disorder in humans...

, metachromatic leukodystrophy

Metachromatic leukodystrophy

Metachromatic leukodystrophy is a lysosomal storage disease which is commonly listed in the family of leukodystrophies. Leukodystrophies affect the growth and/or development of myelin, the fatty covering which acts as an insulator around nerve fibers throughout the central and peripheral nervous...

 (MLD), Krabbe disease

Krabbe disease

Krabbe disease is a rare, often fatal degenerative disorder that affects the myelin sheath of the nervous system. This condition is inherited in an autosomal recessive pattern...

, multiple sulfatase deficiency

Multiple sulfatase deficiency

Multiple sulfatase deficiency is a very rare autosomal recessive lysosomal storage disease caused by a deficiency in multiple sulfatase enzymes...

, Farber disease

Farber disease

Farber disease is an extremely rare autosomal recessive lysosomal storage disease that cause an accumulation of fatty material lipids leading to abnormalities in the joints, liver, throat, tissues and central nervous system...

, and Wolman disease

Wolman disease

Wolman Disease Wolman Disease Wolman Disease (also known as Wolman’s Disease, early onset LAL Deficiency, and Lysosomal acid lipase deficiency is a rare genetic disorder caused by a deficiency of an enzyme known as lysosomal acid lipase (LAL or LIPA). This enzyme is necessary to break down certain...

.

Inheritance

Lipid storage diseases can be inherited two ways:
Autosomal recessive inheritance occurs when both parents carry and pass on a copy of the faulty gene, but neither parent show signs and symptoms of the condition and is not affected by the disorder. Each child born to these parents has a 25 percent chance of inheriting both copies of the defective gene, a 50 percent chance of being a carrier, and a 25 percent chance of not inheriting either copy of the defective gene. Children of either gender can be affected by an autosomal recessive this pattern of inheritance.

X-linked recessive

X-linked recessive

X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males and in females who are homozygous for the gene mutation X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on...

(or sex linked) inheritance occurs when the mother carries the affected gene on the X chromosome that determines the child’s gender and passes it to her son. Sons of carriers have a 50 percent chance of inheriting the disorder. Daughters have a 50 percent chance of inheriting the X-linked chromosome but usually are not severely affected by the disorder. Affected men do not pass the disorder to their sons but their daughters will be carriers for the disorder.