Hypomyelination-congenital cataract syndrome

Last updated
Hypomyelination-congenital cataract syndrome
Other namesHCC
Autosomal recessive - en.svg
Specialty Medical genetics
PreventionNone
Prognosis Medium
Frequencyrare, only 24 cases have been described in medical literature
Deaths-

Hypomyelination-congenital cataract syndrome is a rare autosomal recessive hereditary disorder that affects the brain's white matter [1] and is characterized by congenital cataract (or cataracts that begin in the first two months of life), psychomotor development delays, and moderate intellectual disabilities. It is a type of leukoencephalopathy. [2]

Contents

Signs and symptoms

Children with this condition are born with congenital cataract (or they have an early-onset cataract which presents before two months of life). These cataracts are caused by hypomyelination, which is the body's inability of producing nerve fiber myelin. [3] Development is normal for kids with this condition until the age of 1 year of life, when development and learning start slowing down, although they can learn how to walk. [3]

Other symptoms such as intellectual disabilities, cognitive impairment, epilepsy, ataxia, spasticity, trunk hypotonia, hyperreflexia, tremors, and difficulties with speech are also seen in patients. [3] [4] [5] [6]

Complications

Due to the hypomyelination mentioned beforehand, individuals with this condition start losing sensation in their arms and legs, something which is known medically as peripheral neuropathy. [3] Although walking can be achieved by the age of 1, it can be impaired later in life due to a progressive scoliosis and muscle weakness with accompanying muscle atrophy which are often seen in patients with the condition. [3]

Congenital cataract results in visual impairment. [3]

Genetics

This condition is caused by autosomal recessive mutations in the FAM126A gene, located in chromosome 7. These mutations can either be deletions, loss-of-function, or be caused by amino acid substitutions. [7] [8] These mutations prevent FAM126 from making hyccin, this absence of hyccin is what causes the impaired ability of producing myelin in individuals with this condition. [7] [8]

Other mutations involved in hypomyelination-congenital cataract syndrome actually allow the production of a reasonable amount of hyccin, individuals with this kind of mutations don't experience peripheral neuropathy and they keep the ability of walking for a longer period of time than those who have the more common loss-of-function FAM126A mutations. [7]

Management

The walking impairments can be managed with physical support.[ citation needed ]

The congenital catact can be managed with intraocular lens corrective surgery, after this surgery, contact lenses can be used for the child to be able to see correctly. [9]

Prevalence

According to OMIM, 24 cases from 13 families in Turkey and Italy have been described in medical literature. [10]

See also

References

  1. ↑ Rossi, A.; Biancheri, R.; Zara, F.; Bruno, C.; Uziel, G.; Knaap, M. S. van der; Minetti, C.; Tortori-Donati, P. (2008-02-01). "Hypomyelination and Congenital Cataract: Neuroimaging Features of a Novel Inherited White Matter Disorder". American Journal of Neuroradiology. 29 (2): 301–305. doi: 10.3174/ajnr.A0792 . ISSN   0195-6108. PMC   8118974 . PMID   17974614.
  2. ↑ RESERVED, INSERM US14-- ALL RIGHTS. "Orphanet: Hypomyelination congenital cataract syndrome". www.orpha.net. Retrieved 2022-07-13.{{cite web}}: CS1 maint: numeric names: authors list (link)
  3. 1 2 3 4 5 6 "Hypomyelination and congenital cataract: MedlinePlus Genetics". medlineplus.gov. Retrieved 2022-07-13.
  4. ↑ "Hypomyelination and congenital cataract | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program". 2021-04-12. Archived from the original on 2021-04-12. Retrieved 2022-07-13.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  5. ↑ Roberts, Sean. "Hypomyelination and congenital cataract". NORD (National Organization for Rare Disorders). Retrieved 2022-07-13.
  6. ↑ Wolf, Nicole I.; Biancheri, Roberta; Zara, Federico; Bruno, Claudio; Gazzerro, Elisabetta; Rossi, Andrea; van der Knaap, Marjo S.; Minetti, Carlo (1993), Adam, Margaret P.; Mirzaa, Ghayda M.; Pagon, Roberta A.; Wallace, Stephanie E. (eds.), "Hypomyelination and Congenital Cataract", GeneReviews®, Seattle (WA): University of Washington, Seattle, PMID   20301737 , retrieved 2022-07-14
  7. 1 2 3 "FAM126A gene: MedlinePlus Genetics". medlineplus.gov. Retrieved 2022-07-13.
  8. 1 2 Biancheri, Roberta; Zara, Federico; Rossi, Andrea; Mathot, Mikael; Nassogne, Marie Cecile; Yalcinkaya, Cengiz; Erturk, Ozdem; Tuysuz, Behyan; Di Rocco, Maja; Gazzerro, Elisabetta; Bugiani, Marianna (2011-09-01). "Hypomyelination and Congenital Cataract: Broadening the Clinical Phenotype". Archives of Neurology. 68 (9): 1191–1194. doi: 10.1001/archneurol.2011.201 . ISSN   0003-9942.
  9. ↑ "Congenital cataracts". www.marchofdimes.org. Retrieved 2022-07-13.
  10. ↑ "Entry - #610532 - Leukodystrophy, hypomyelinating, 5; HLD5 - OMIM". omim.org. Retrieved 2022-07-13.
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