Related Experiment Videos
The neurogenetics of mucolipidosis type IV
G Altarescu1, M Sun, D F Moore
1Developmental and Metabolic Neurology Branch, National Institute of Neurologic Disorders and Stroke/NIH, 9000 Rockville Pike, Building 10, Rm. 3D03, Bethesda, MD 20892-1260, USA.
Background:
Mucolipidosis type IV (MLIV) is an autosomal recessive disease caused by mutations in the MCOLN1 gene that codes for mucolipin, a member of the transient receptor potential (TRP) gene family.
Objective:
To comprehensively characterize the clinical and genetic abnormalities of MLIV.
Methods:
Twenty-eight patients with MLIV, aged 2 to 25 years, were studied. Ten returned for follow-up every 1 to 2 years for up to 5 years. Standard clinical, neuroimaging, neurophysiologic, and genetic techniques were used.
Results:
All patients had varying degrees of corneal clouding, with progressive optic atrophy and retinal dystrophy. Twenty-three patients had severe motor and mental impairment. Motor function deteriorated in three patients and remained stable in the rest. All had a constitutive achlorhydria with elevated plasma gastrin level, and 12 had iron deficiency or anemia. Head MRI showed consistent characteristic findings of a thin corpus callosum and remained unchanged during the follow-up period. Prominent abnormalities of speech, hand usage, and swallowing were also noted. Mutations in the MCOLN1 gene were present in all patients. Correlation of the genotype with the neurologic handicap and corpus callosum dysplasia was found.
Conclusions:
MLIV is both a developmental and a degenerative disorder. The presentation as a cerebral palsy-like encephalopathy may delay diagnosis.
Insights
Mucolipidosis type IV (MLIV) is a genetic disorder affecting development and causing degeneration. MCOLN1 gene mutations are present in all patients, correlating with neurological and brain abnormalities.
Area of Science:
- Genetics
- Neuroscience
- Ophthalmology
Background:
- Mucolipidosis type IV (MLIV) is an autosomal recessive genetic disorder.
- It results from mutations in the MCOLN1 gene, which encodes mucolipin, a TRP channel protein.
Purpose of the Study:
- To comprehensively characterize the clinical and genetic abnormalities in MLIV patients.
- To investigate the correlation between genotype and clinical presentation.
Main Methods:
- Studied 28 MLIV patients (ages 2-25) with standard clinical, neuroimaging, neurophysiologic, and genetic techniques.
- Follow-up for up to 5 years in 10 patients.
Main Results:
- All patients exhibited corneal clouding, optic atrophy, and retinal dystrophy.
- 23 patients had severe motor/mental impairment; 12 had iron deficiency/anemia.
- Consistent MRI findings included a thin corpus callosum; MCOLN1 mutations were found in all patients, correlating with neurological deficits.
Conclusions:
- MLIV presents as both a developmental and degenerative disorder.
- Its cerebral palsy-like encephalopathy presentation can lead to diagnostic delays.