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Leukodystrophy, hypomyelinating, 25(HLD25)

MedGen UID:
1840911
Concept ID:
C5830275
Disease or Syndrome
Synonym: HLD25
 
Gene (location): TMEM163 (2q21.3)
 
Monarch Initiative: MONDO:0859378
OMIM®: 620243

Definition

Hypomyelinating leukodystrophy-25 (HLD25) is an autosomal recessive disorder characterized by horizontal nystagmus, hypotonia, and global developmental delay apparent soon after birth or in infancy. Most patients show gradual clinical improvement over time with resolution of the nystagmus in early childhood. Many achieve developmental milestones and may have normal cognition, although the severity of the disorder varies and some patients may have persistent neurologic deficits, such as ataxia or intellectual disability. Brain imaging shows hypomyelination that may also improve with time (Yan et al., 2022; do Rosario et al., 2022). For a general phenotypic description and a discussion of genetic heterogeneity of HLD, see 312080. [from OMIM]

Clinical features

From HPO
Growth delay
MedGen UID:
99124
Concept ID:
C0456070
Pathologic Function
A deficiency or slowing down of growth pre- and postnatally.
Dysarthria
MedGen UID:
8510
Concept ID:
C0013362
Mental or Behavioral Dysfunction
Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.
Dystonic disorder
MedGen UID:
3940
Concept ID:
C0013421
Sign or Symptom
An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.
Seizure
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Intellectual disability, severe
MedGen UID:
48638
Concept ID:
C0036857
Mental or Behavioral Dysfunction
Severe mental retardation is defined as an intelligence quotient (IQ) in the range of 20-34.
Diminished ability to concentrate
MedGen UID:
65900
Concept ID:
C0235198
Finding
The inability to focus or concentrate on a specific task, activity, or object. The subject may find themselves unable to grasp or understand written text and re-reads frequently without understanding. Familiar tasks or activities are severely compromised due to the lack of ability to concentrate. Thinking through multi-step problems is typically very difficult or impossible, leading to avoidance of such activities.
Delayed ability to walk
MedGen UID:
66034
Concept ID:
C0241726
Finding
A failure to achieve the ability to walk at an appropriate developmental stage. Most children learn to walk in a series of stages, and learn to walk short distances independently between 12 and 15 months.
Delayed speech and language development
MedGen UID:
105318
Concept ID:
C0454644
Finding
A degree of language development that is significantly below the norm for a child of a specified age.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Gait ataxia
MedGen UID:
155642
Concept ID:
C0751837
Sign or Symptom
A type of ataxia characterized by the impairment of the ability to coordinate the movements required for normal walking. Gait ataxia is characteirzed by a wide-based staggering gait with a tendency to fall.
Reduced eye contact
MedGen UID:
303190
Concept ID:
C1445953
Finding
A reduced frequency or duration of eye contact.
Mild global developmental delay
MedGen UID:
861405
Concept ID:
C4012968
Finding
A mild delay in the achievement of motor or mental milestones in the domains of development of a child.
Delayed CNS myelination
MedGen UID:
867393
Concept ID:
C4021758
Anatomical Abnormality
Delayed myelination in the central nervous system.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Nystagmus
MedGen UID:
45166
Concept ID:
C0028738
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
Blue sclerae
MedGen UID:
154236
Concept ID:
C0542514
Finding
An abnormal bluish coloration of the sclera.

Recent clinical studies

Etiology

Biglari S, Vahidnezhad H, Tabatabaiefar MA, Khorram Khorshid HR, Esmaeilzadeh E
Mol Genet Genomic Med 2024 Apr;12(4):e2435. doi: 10.1002/mgg3.2435. PMID: 38618971Free PMC Article
Wong MST, Thomas T, Lim JY, Kam S, Teo JX, Ching J, Goh CYJ, Jamuar SS, Lim WK, Koh AL
Clin Dysmorphol 2023 Jul 1;32(3):106-111. Epub 2023 May 1 doi: 10.1097/MCD.0000000000000457. PMID: 37195341
Wu C, Wang M, Wang X, Li W, Li S, Chen B, Niu S, Tai H, Pan H, Zhang Z
Brain 2023 Jun 1;146(6):2364-2376. doi: 10.1093/brain/awac426. PMID: 36380532Free PMC Article
Kraoua I, Karkar A, Drissi C, Benrhouma H, Klaa H, Samaan S, Renaldo F, Elmaleh M, Ben Hamouda M, Abdelhak S, Boespflug-Tanguy O, Ben Youssef-Turki I, Dorboz I
Mol Genet Genomic Med 2019 Sep;7(9):e914. Epub 2019 Jul 31 doi: 10.1002/mgg3.914. PMID: 31368241Free PMC Article
Duignan S, Wright S, Rossor T, Cazabon J, Gilmour K, Ciccarelli O, Wassmer E, Lim M, Hemingway C, Hacohen Y
Dev Med Child Neurol 2018 Sep;60(9):958-962. Epub 2018 Feb 22 doi: 10.1111/dmcn.13703. PMID: 29468668

Diagnosis

Wu C, Wang M, Wang X, Li W, Li S, Chen B, Niu S, Tai H, Pan H, Zhang Z
Brain 2023 Jun 1;146(6):2364-2376. doi: 10.1093/brain/awac426. PMID: 36380532Free PMC Article
Di Bella D, Magri S, Benzoni C, Farina L, Maccagnano C, Sarto E, Moscatelli M, Baratta S, Ciano C, Piacentini SHMJ, Draghi L, Mauro E, Pareyson D, Gellera C, Taroni F, Salsano E
Eur J Neurol 2021 Mar;28(3):934-944. Epub 2020 Dec 3 doi: 10.1111/ene.14646. PMID: 33190326
Duignan S, Wright S, Rossor T, Cazabon J, Gilmour K, Ciccarelli O, Wassmer E, Lim M, Hemingway C, Hacohen Y
Dev Med Child Neurol 2018 Sep;60(9):958-962. Epub 2018 Feb 22 doi: 10.1111/dmcn.13703. PMID: 29468668
Ghoumid J, Petit F, Boute-Benejean O, Frenois F, Cartigny M, Vanlerberghe C, Smol T, Caumes R, de Roux N, Manouvrier-Hanu S
Eur J Hum Genet 2017 Aug;25(8):1011-1014. Epub 2017 Jun 7 doi: 10.1038/ejhg.2017.73. PMID: 28589944Free PMC Article
Borck G, Hög F, Dentici ML, Tan PL, Sowada N, Medeira A, Gueneau L, Thiele H, Kousi M, Lepri F, Wenzeck L, Blumenthal I, Radicioni A, Schwarzenberg TL, Mandriani B, Fischetto R, Morris-Rosendahl DJ, Altmüller J, Reymond A, Nürnberg P, Merla G, Dallapiccola B, Katsanis N, Cramer P, Kubisch C
Genome Res 2015 Feb;25(2):155-66. Epub 2015 Jan 5 doi: 10.1101/gr.176925.114. PMID: 25561519Free PMC Article

Prognosis

Kraoua I, Karkar A, Drissi C, Benrhouma H, Klaa H, Samaan S, Renaldo F, Elmaleh M, Ben Hamouda M, Abdelhak S, Boespflug-Tanguy O, Ben Youssef-Turki I, Dorboz I
Mol Genet Genomic Med 2019 Sep;7(9):e914. Epub 2019 Jul 31 doi: 10.1002/mgg3.914. PMID: 31368241Free PMC Article
Duignan S, Wright S, Rossor T, Cazabon J, Gilmour K, Ciccarelli O, Wassmer E, Lim M, Hemingway C, Hacohen Y
Dev Med Child Neurol 2018 Sep;60(9):958-962. Epub 2018 Feb 22 doi: 10.1111/dmcn.13703. PMID: 29468668

Clinical prediction guides

Rudzińska I, Cieśla M, Turowski TW, Armatowska A, Leśniewska E, Boguta M
Int J Mol Sci 2021 Jul 7;22(14) doi: 10.3390/ijms22147298. PMID: 34298922Free PMC Article
Kraoua I, Karkar A, Drissi C, Benrhouma H, Klaa H, Samaan S, Renaldo F, Elmaleh M, Ben Hamouda M, Abdelhak S, Boespflug-Tanguy O, Ben Youssef-Turki I, Dorboz I
Mol Genet Genomic Med 2019 Sep;7(9):e914. Epub 2019 Jul 31 doi: 10.1002/mgg3.914. PMID: 31368241Free PMC Article

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