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Which muscles are affected by FSHD?

Facioscapulohumeral muscular dystrophy (FSHD) is a disorder characterized by muscle weakness and wasting (atrophy). The disorder gets its name from muscles that are affected in the face (facio), around the shoulder blades (scapulo), and in the upper arms (humeral).

How many people have FSH?

Estimates of frequency have varied from one in about 400,000 to one in 20,000.

How is FSHD passed down?

A mutation from one parent is sufficient to cause FSHD FSHD1 is inherited in an autosomal dominant pattern, meaning it takes only one mutation (from one parent) to cause the disorder.

Is facioscapulohumeral muscular dystrophy progressive?

The two sides of the body are often affected unequally. Weakness typically manifests at ages 15 – 30 years. FSHD can also cause hearing loss and blood vessel abnormalities in the back of the eye….

Facioscapulohumeral muscular dystrophy
Prognosis Progressive, unaffected life expectancy
Frequency Up to 1/8,333

How common is FSH muscular dystrophy?

FSHD is the third most common type of muscular dystrophy, behind Duchenne and Becker muscular dystrophies and myotonic dystrophy. The estimated prevalence of FSHD about 4 cases per 100,000 individuals.

Is FSH muscular dystrophy fatal?

FSHD usually progresses very slowly and rarely affects the heart or respiratory system. Most people with the disease have a normal life span.

Which is rarer FSHD Type 1 or 2?

Facioscapulohumeral muscular dystrophy Type 2 (also called FSHD1B or FSHMD1B) is much rarer than Type 1 and is thought to account for the majority of the 5 percent of FSHD cases that test negative for Type 1. FSHD2 is clinically identical to FSHD1 but genetically distinct.

What are the genetic causes of FSHD Type 2?

The remaining 5 percent is called FSHD Type 2 (FSHD2), and around 80 percent of these cases are linked to mutations in a gene called SMCHD1. There are around 1 percent that have not yet been traced to a genetic cause.

What’s the difference between FSHD 1 and 2?

FSHD2 is clinically identical to FSHD1 but genetically distinct. In FSHD1, the tandem repeats called D4Z4 on chromosome 4 are deleted, whereas in FSHD2, the number of D4Z4 repeats is in the normal range.

What is the function of the ARG1 gene?

The ARG1 gene provides instructions for producing the enzyme arginase. This enzyme participates in the urea cycle, a series of reactions that occurs in liver cells. The urea cycle processes excess nitrogen, which is generated when proteins and their building blocks (amino acids) are used by the body.