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  • CN376030 has been replaced by C5882743, showing C5882743

Leukodystrophy, hypomyelinating, 27(HLD27)

MedGen UID:
1844996
Concept ID:
C5882743
Disease or Syndrome
Synonym: HLD27
 
Gene (location): POLR1A (2p11.2)
 
Monarch Initiative: MONDO:0958018
OMIM®: 620675

Definition

Hypomyelinating leukodystrophy-27 (HLD27) is an autosomal recessive neurologic disorder characterized by global developmental delay with impaired motor and intellectual development apparent from infancy. Affected individuals have poor or absent speech, ataxic gait or inability to sit or walk, spasticity, and abnormal eye movements (nystagmus, gaze palsy). Some patients have seizures. Disease progression and developmental regression consistent with neurodegeneration is often observed. Brain imaging shows progressive hypomyelinating leukodystrophy, cerebral and cerebellar atrophy, and thin corpus callosum (Misceo et al., 2023). For a general phenotypic description and a discussion of genetic heterogeneity of HLD, see 312080. [from OMIM]

Clinical features

From HPO
Pes cavus
MedGen UID:
675590
Concept ID:
C0728829
Congenital Abnormality
An increase in height of the medial longitudinal arch of the foot that does not flatten on weight bearing (i.e., a distinctly hollow form of the sole of the foot when it is bearing weight).
Small for gestational age
MedGen UID:
65920
Concept ID:
C0235991
Finding
Smaller than normal size according to sex and gestational age related norms, defined as a weight below the 10th percentile for the gestational age.
Short stature
MedGen UID:
87607
Concept ID:
C0349588
Finding
A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).
Feeding difficulties
MedGen UID:
65429
Concept ID:
C0232466
Finding
Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.
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.
Leukodystrophy
MedGen UID:
6070
Concept ID:
C0023520
Disease or Syndrome
Leukodystrophy refers to deterioration of white matter of the brain resulting from degeneration of myelin sheaths in the CNS. Their basic defect is directly related to the synthesis and maintenance of myelin membranes. Symmetric white matter involvement at MRI is a typical finding in patients with leukodystrophies.
Spasticity
MedGen UID:
7753
Concept ID:
C0026838
Sign or Symptom
A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.
Babinski sign
MedGen UID:
19708
Concept ID:
C0034935
Finding
Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract.
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.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
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.
Truncal ataxia
MedGen UID:
96535
Concept ID:
C0427190
Sign or Symptom
Truncal ataxia is a sign of ataxia characterized by instability of the trunk. It usually occurs during sitting.
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.
Cerebellar atrophy
MedGen UID:
196624
Concept ID:
C0740279
Disease or Syndrome
Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event.
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.
Head titubation
MedGen UID:
299071
Concept ID:
C1608410
Sign or Symptom
A head tremor of moderate speed (3 to 4 Hz) in the anterior-posterior direction.
Developmental regression
MedGen UID:
324613
Concept ID:
C1836830
Disease or Syndrome
Loss of developmental skills, as manifested by loss of developmental milestones.
Loss of ambulation
MedGen UID:
332305
Concept ID:
C1836843
Finding
Inability to walk in a person who previous had the ability to walk.
Absent speech
MedGen UID:
340737
Concept ID:
C1854882
Finding
Complete lack of development of speech and language abilities.
Irritability
MedGen UID:
397841
Concept ID:
C2700617
Mental Process
A proneness to anger, i.e., a tendency to become easily bothered or annoyed.
Ventriculomegaly
MedGen UID:
480553
Concept ID:
C3278923
Finding
An increase in size of the ventricular system of the brain.
Intellectual disability
MedGen UID:
811461
Concept ID:
C3714756
Mental or Behavioral Dysfunction
Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.
Atrophy/Degeneration affecting the brainstem
MedGen UID:
870454
Concept ID:
C4024900
Disease or Syndrome
CNS hypomyelination
MedGen UID:
892446
Concept ID:
C4025616
Finding
Reduced amount of myelin in the central nervous system resulting from defective myelinogenesis.
Thin corpus callosum
MedGen UID:
1785336
Concept ID:
C5441562
Anatomical Abnormality
An abnormally thin corpus callous, due to atrophy, hypoplasia or agenesis. This term is intended to be used in situations where it is not known if thinning of the corpus callosum (for instance, as visualized by magnetic resonance tomography) is due to abnormal development (e.g. a leukodystrophy) or atrophy following normal development (e.g. neurodegeneration).
Hypertonia
MedGen UID:
10132
Concept ID:
C0026826
Finding
A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move.
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.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
Poor head control
MedGen UID:
322809
Concept ID:
C1836038
Finding
Difficulty to maintain correct position of the head while standing or sitting. Infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk. Several articles have maintained that head lag should be absent by age 3 to 4 months.
Joint hypermobility
MedGen UID:
336793
Concept ID:
C1844820
Finding
The capability that a joint (or a group of joints) has to move, passively and/or actively, beyond normal limits along physiological axes.
Relative macrocephaly
MedGen UID:
338607
Concept ID:
C1849075
Congenital Abnormality
A relatively mild degree of macrocephaly in which the head circumference is not above two standard deviations from the mean, but appears dysproportionately large when other factors such as body stature are taken into account.
Neonatal hypoglycemia
MedGen UID:
57646
Concept ID:
C0158986
Finding
Blood glucose concentration below the lower limit of established reference ranges in a newborn.
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.
Optic atrophy
MedGen UID:
18180
Concept ID:
C0029124
Disease or Syndrome
Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy.
Strabismus
MedGen UID:
21337
Concept ID:
C0038379
Disease or Syndrome
A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error.
Cataract
MedGen UID:
39462
Concept ID:
C0086543
Disease or Syndrome
A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.
Supranuclear gaze palsy
MedGen UID:
314030
Concept ID:
C1720037
Disease or Syndrome
A supranuclear gaze palsy is an inability to look in a particular direction as a result of cerebral impairment. There is a loss of the voluntary aspect of eye movements, but, as the brainstem is still intact, all the reflex conjugate eye movements are normal.

Professional guidelines

PubMed

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Diagnosis

Ashrafi M, Kameli R, Hosseinpour S, Razmara E, Zamani Z, Rezaei Z, Mashayekhi R, Pak N, Barzegar M, Azizimalamiri R, Kashani MR, Khosroshahi N, Rasulinezhad M, Heidari M, Amanat M, Abdi A, Mohammadi B, Mohammadi M, Zamani GR, Badv RS, Omrani A, Nikbakht S, Bereshneh AH, Movahedinia M, Moghaddam HF, Ardakani HS, Akbari MG, Tousi MB, Shahi MV, Hosseini F, Amouzadeh MH, Hosseini SA, Nikkhah A, Khajeh A, Alizadeh H, Yarali B, Rohani M, Karimi P, Elahi HML, Hosseiny SMM, Sadeghzadeh MS, Mohebbi H, Moghadam MH, Aryan H, Vahidnezhad H, Soveizi M, Rabbani B, Rabbani A, Mahdieh N, Garshasbi M, Tavasoli AR
Neurogenetics 2023 Oct;24(4):279-289. Epub 2023 Aug 19 doi: 10.1007/s10048-023-00730-y. PMID: 37597066
Malik P, Muthusamy K, Mankad K, Shroff M, Sudhakar S
Eur J Paediatr Neurol 2020 Jul;27:9-24. Epub 2020 Apr 22 doi: 10.1016/j.ejpn.2020.04.007. PMID: 32418752
Anheim M, Torres Martin JV, Kolb SA
Cerebellum 2020 Apr;19(2):243-251. doi: 10.1007/s12311-020-01102-0. PMID: 31933160
Chelban V, Alsagob M, Kloth K, Chirita-Emandi A, Vandrovcova J, Maroofian R, Davagnanam I, Bakhtiari S, AlSayed MD, Rahbeeni Z, AlZaidan H, Malintan NT, Johannsen J, Efthymiou S, Ghayoor Karimiani E, Mankad K, Al-Shahrani SA, Beiraghi Toosi M, AlShammari M, Groppa S, Haridy NA, AlQuait L, Qari A, Huma R, Salih MA, Almass R, Almutairi FB, Hamad MH, Alorainy IA, Ramzan K, Imtiaz F, Puiu M, Kruer MC, Bierhals T, Wood NW, Colak D, Houlden H, Kaya N
Eur J Neurol 2020 Feb;27(2):334-342. Epub 2019 Oct 17 doi: 10.1111/ene.14082. PMID: 31509304Free PMC Article
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Therapy

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Eur J Neurol 2020 Feb;27(2):334-342. Epub 2019 Oct 17 doi: 10.1111/ene.14082. PMID: 31509304Free 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
Miyake N, Wolf NI, Cayami FK, Crawford J, Bley A, Bulas D, Conant A, Bent SJ, Gripp KW, Hahn A, Humphray S, Kimura-Ohba S, Kingsbury Z, Lajoie BR, Lal D, Micha D, Pizzino A, Sinke RJ, Sival D, Stolte-Dijkstra I, Superti-Furga A, Ulrick N, Taft RJ, Ogata T, Ozono K, Matsumoto N, Neubauer BA, Simons C, Vanderver A
Neurogenetics 2017 Dec;18(4):185-194. Epub 2017 Aug 26 doi: 10.1007/s10048-017-0520-x. PMID: 28842795Free PMC Article
Kristjánsdóttir R, Uvebrant P, Hagberg B, Kyllerman M, Wiklund LM, Blennow G, Flodmark O, Gustavsson L, Ekholm S, Månsson JE
Neuropediatrics 1996 Dec;27(6):295-8. doi: 10.1055/s-2007-973797. PMID: 9050046

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