Leukodystrophy, Hypomyelinating, 5 (HLD5)

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MedlinePlus Genetics: ⁴² Hypomyelination and congenital cataract is an inherited condition that affects the nervous system and the eyes. This disease is one of a group of genetic disorders called leukoencephalopathies. Leukoencephalopathies involve abnormalities of the brain's white matter. White matter consists of nerve fibers covered by a fatty substance called myelin. Myelin insulates nerve fibers and promotes the rapid transmission of nerve impulses. Hypomyelination and congenital cataract is caused by a reduced ability to form myelin (hypomyelination). Additionally, people with this disorder are typically born with a clouding of the lens (cataract) in both eyes.People with this condition usually have normal development throughout the first year of life. Development slows around the age of 1. Most affected children learn to walk between the ages of 1 and 2, although they usually need some type of support. Over time they experience muscle weakness and wasting (atrophy) in their legs, and many affected people eventually require wheelchair assistance. Weakness in the muscles of the trunk and a progressive abnormal curvature of the spine (scoliosis) further impair walking in some individuals. Most people with hypomyelination and congenital cataract have reduced sensation in their arms and legs (peripheral neuropathy). In addition, affected individuals typically have speech difficulties (dysarthria) and mild to moderate intellectual disability.

MalaCards based summary: Leukodystrophy, Hypomyelinating, 5, also known as hypomyelination and congenital cataract, is related to spasticity and leukodystrophy, and has symptoms including action tremor, abnormal pyramidal signs and cerebellar signs. An important gene associated with Leukodystrophy, Hypomyelinating, 5 is HYCC1 (Hyccin PI4KA Lipid Kinase Complex Subunit 1), and among its related pathways/superpathways are Oligodendrocyte specification and differentiation, leading to myelin components for CNS and Glial cell differentiation. Affiliated tissues include eye, brain and cerebellum, and related phenotypes are abnormal pyramidal sign and global developmental delay

GARD: ¹⁹ Hypomyelination and congenital cataract is a very rare disease characterized by cloudy coverings of the eye that are present at birth (congenital cataracts) and neurologic impairment that becomes apparent after the first year of life. The neurologic impairment is progressive and presents as ataxia and spasticity. Affected individuals may lose the ability to walk. Signs and symptoms may vary but can include loss of sensation in the hands and feet (peripheral neuropathy), curvature of the spine (scoliosis), difficulty speaking (dysarthria), seizures, and moderate intellectual disability. Hypomyelination and congenital cataract is caused by a change (genetic change ) in the FAM126A gene and is inherited in an autosomal recessive manner. Diagnosis of Hypomyelination and congenital cataract is based on clinical findings of muscle weakness and cataracts, and a brain MRI that indicates a loss of the myelin surrounding the neurons. The diagnosis can be confirmed by genetic testing of the FAM126A gene.

UniProtKB/Swiss-Prot: ⁷³ A hypomyelinating leukodystrophy associated with congenital cataract. It is clinically characterized by congenital cataract, progressive neurologic impairment, and diffuse myelin deficiency. Affected individuals experience progressive pyramidal and cerebellar dysfunction, muscle weakness and wasting prevailingly in the lower limbs. Mental deficiency ranges from mild to moderate. HLD5 shows clinical variability, but features of hypomyelination combined with increased periventricular white matter water content are consistently observed.

Disease Ontology: ¹¹ A hypomyelinating leukodystrophy characterized by autosomal recessive inheritance of congenital cataract, progressive neurologic impairment, and diffuse myelin deficiency that has material basis in homozygous mutation in the FAM126A gene on chromosome 7p15.

Orphanet: ⁵⁸ Hypomyelination-congenital cataract is characterized by the onset of cataract either at birth or in the first two months of life, delayed psychomotor development by the end of the first year of life and moderate intellectual deficit.

Wikipedia: ⁷⁵ Hypomyelination-congenital cataract syndrome is a rare autosomal recessive hereditary disorder that... more...

Clinical features from OMIM®:

Search Clinical Trials, NIH Clinical Center for Leukodystrophy, Hypomyelinating, 5