Glycogen Storage Disease Type II (Pompe) Screening -Infant

Glycogen Storage Disease Type II (Pompe) Screening -Infant

Glycogen Storage Disease Type II (Pompe) Screening

Summary of Recommendation and Evidence

Population

Recommendation

Grade
(What's This?)

Screening of both Genders

The genetic screening for Glycogen Storage Disease Type II (Pompe) is recommended.

B

Glycogen storage disease type II, also called Pompe disease, is an autosomal recessive metabolic disorder which damages muscle and nerve cells throughout the body.

OVERVIEW

Pompe disease is an inherited disorder caused by the buildup of a complex sugar called glycogen in the body's cells. The accumulation of glycogen in certain organs and tissues, especially muscles, impairs their ability to function normally.

PREVALENCE

Pompe disease affects about 1 in 40,000 people in the United States. The incidence of this disorder varies among different ethnic groups.

INHERITANCE

Pompe disease  is inherited in an autosomal recessive manner. It affects both boys and girls equally.

CLINICAL CHARACTERISTICS

Signs & Symptoms 

Patients with the classic infantile form of Pompe disease are the most severely affected. Although hardly any symptoms may be apparent at birth, the disease usually presents within the first three months of life with rapidly progressive muscle weakness (floppy infants), diminished muscle tone (hypotonia), respiratory insufficiency, and a type of heart disease known as hypertrophic cardiomyopathy, a condition characterized by abnormal thickening of the walls of the heart (mainly the left chamber and the wall between the left and right chamber) resulting in diminished cardiac function. These problems together culminate in cardio-respiratory failure within the first 2 years of life.

Many infants have a large, protruding tongue and a moderate enlargement of the liver. The legs often rest in a frog position and feel firm on palpation (pseudo-hypertrophy).

EARLY SIGNS

The severity and age of onset of Pompe differ depending on the form.

Signs of classic infantile-onset Pompe begin before or shortly after birth and include:

  • Muscle weakness (myopathy)
  • Poor muscle tone (hypotonia)
  • Failure to gain weight and grow at expected rate (failure to thrive)
  • Difficulty breathing
  • Trouble feeding
  • Respiratory infections
  • Hearing problems

Signs of non-classic infantile-onset Pompe usually occur by age one and include:

  • Delayed motor skills
  • Progressive muscle weakness (myopathy)
  • Difficulty breathing

Late-onset Pompe may develop in childhood, adolescence, or even adulthood. It is also associated with progressive muscular weakness and difficulty breathing. However, the symptoms are usually milder and progress more slowly than the other forms of Pompe.

CAUSES

Structures called lysosomes are the recycling centers within our cells. Lysosomes contain enzymes that help the cell breakdown and reuse certain materials from the foods we eat. Some enzymes help the lysosome breakdown complex sugars, specifically. One of these enzymes is called acid alpha-glucosidase (GAA). 

If your baby has Pompe, his or her body is missing or making non-working copies of GAA enzymes. When this enzyme is not working correctly, your baby’s body cannot break down a large sugar molecule called glycogen into smaller components. This causes undigested sugar molecules and other harmful substances to build up in cells throughout the body, resulting in the many signs and symptoms of Pompe.

Pompe is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for Pompe, one from each parent, in order to have the condition. The parents of a child with an autosomal recessive condition each carry one copy of the non-working gene, but they typically do not show signs and symptoms of the condition.

While having a child with Pompe is rare, when both parents are carriers, they can have more than one child with the condition.

TREATMENT

Enzyme Replacement Therapy

Your baby’s health care provider may recommend your baby go on enzyme replacement therapy (ERT) to improve the signs and symptoms of Pompe. This treatment aims to supplement the enzymes that are present at low levels in your baby’s lysosomes.  ERT can stabilize your baby’s organ function, improving motor skills, and reducing heart enlargement. 

Physical Therapy

Physical therapy will be necessary to help infants, children, and adolescents develop motor skills, maintain range of motion, and strengthen muscles and joints.

Respiratory Therapy

Because lung infections and breathing difficulties are common in children with Pompe, your baby may need to use a CPAP or BiPAP machine. A CPAP machine helps to keep your child’s airways open and a BiPAP machine helps your child inhale more air into his or her lungs.

Dietary Treatments
Many babies with Pompe have trouble feeding and gaining weight. A nutritionist or dietician can help you monitor your baby’s calorie intake and plan a diet that will provide the nutrients he or she needs for proper growth and development. Some children with Pompe are managed on a soft diet, while others may require a feeding tube.

EXPECTED OUTCOMES
When Pompe is detected early and proper treatment is started immediately, many babies with the condition are able to live longer lives with improved growth, development and organ function. This is why newborn screening for Pompe is so important.

Even with treatment, children with both forms of infantile-onset Pompe usually pass away in early childhood. Individuals with late-onset Pompe often have longer lifespans with slower disease progression.