TN 28 (08-20)

DI 23022.186 GM1 - Gangliosidosis - Infantile & Juvenile Forms

COMPASSIONATE ALLOWANCES INFORMATION

GM1 - GANGLIOSIDOSIS - INFANTILE & JUVENILE FORMS

ALTERNATE NAMES

GM1 gangliosidosis type I; GM1 gangliosidosis type II; beta-galactosidase-1 (GLB1) deficiency; GLB1 deficiency; Landing disease; type 1 GM1 gangliosidosis; type 2 GM1 gangliosidosis; Beta-galactosidosis; Classic infantile (type 1) GM1 gangliosidosis; Juvenile (type 2) GM1 gangliosidosis

DESCRIPTION

GM1 gangliosidosis is a rare lysosomal storage disorder characterized biochemically by deficient beta-galactosidase activity and clinically by a wide range of variable neurovisceral, ophthalmological, and dysmorphic features.

DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM/ICD-10-CM CODING

Diagnostic testing: Diagnosis may be difficult due to the wide clinical spectrum of the disease. Diagnosis is confirmed by:

  • Biochemical assay of beta-galactosidase activity and/or by molecular genetic testing; and

  • A secondary combined defect of both GLB1 and neuraminidase (NEU1) has to be excluded.

Other diagnostic testing includes:

  • Peripheral blood smear (testing vacuolated lymphocytes);

  • Urine oligosaccharides; and

  • Bone marrow examination.

Physical findings: Physical findings for types 1 and 2 GM1 gangliodosis may include:

  • Facial coarsening;

  • Gingival hypertrophy (enlarged gums);

  • Cherry-red macula;

  • Cardiomyopathy (enlarged, weakened heart muscle);

  • Enlarged organs inside of the abdomen, including liver, spleen, stomach, kidneys, or pancreas (visceromegaly);

  • Abnormal development of bones (dysostosis);

  • Developmental regression;

  • Dementia;

  • Ataxia;

  • Seizures;

  • Difficulties with speech; and

  • Psychomotor delay.

ICD-9: 277.89

ICD-10: E75.19

PROGRESSION

Infants with Type 1 GM1 gangliosidosis typically appear normal until around 6 months of age when their development slows and muscles used for movement weaken. Affected children typically do not live past 2 years of age.

Type 2 GM1 gangliosidosis consists of intermediate forms of the condition, also known as the late infantile and juvenile forms. Children with GM1 gangliosidosis type 2 have normal early development, but they begin to develop signs and symptoms of the condition around the age of 18 months (late infantile form) or 5 years (juvenile form). Infants with GM1 gangliosidosis type 2 experience developmental regression but usually do not have cherry-red spots, distinctive facial features, or enlarged organs. Type 2 usually progresses more slowly than type 1, but still causes a shortened life expectancy. Children with the late infantile form typically survive into mid-childhood, while those with the juvenile form may live into early adulthood.

TREATMENT

Treatment for GM1 gangliosidosis is symptomatic and supportive. Substrate reduction therapy is a potential approach for clinical trials in late-onset forms. Prognosis depends on the type of GM1 gangliosidosis and is extremely poor in the severe infantile form.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for Evaluation:

  • Clinical history and examination that describes diagnostic features of the impairment;

  • Results of genetic testing confirming diagnosis of the impairment; and

  • Definitive results of other diagnostic testing.

Suggested Listings for Evaluation:

DETERMINATION

LISTING

REMARKS

Meets 110.08 B
111.02
111.09
112.08
112.14

Equals

* Adjudicators may, at their discretion, use the Medical Evidence of Record or the listings suggested to evaluate the claim. However, the decision to allow or deny the claim rests with the adjudicator.

To Link to this section - Use this URL:
http://policy.ssa.gov/poms.nsf/lnx/0423022186
DI 23022.186 - GM1 - Gangliosidosis - Infantile & Juvenile Forms - 08/13/2020
Batch run: 07/20/2021
Rev:08/13/2020