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Ataxia - intellectual disability - oculomotor apraxia - cerebellar cysts syndrome(PTBHS)

MedGen UID:
863258
Concept ID:
C4014821
Disease or Syndrome
Synonym: Poretti-Boltshauser syndrome
SNOMED CT: Cerebellar ataxia, intellectual disability, oculomotor apraxia, cerebellar cysts syndrome (763344007); Poretti Boltshauser syndrome (763344007)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): LAMA1 (18p11.31)
 
Monarch Initiative: MONDO:0014419
OMIM®: 615960
Orphanet: ORPHA370022

Definition

Poretti-Boltshauser syndrome is an autosomal recessive disorder characterized by cerebellar dysplasia, cerebellar vermis hypoplasia, cerebellar cysts in most patients, high myopia, variable retinal dystrophy, and eye movement abnormalities. Affected individuals have delayed motor development and often have speech delay. Cognitive function can range from normal to intellectually disabled (summary by Aldinger et al., 2014). [from OMIM]

Clinical features

From HPO
Gray matter heterotopia
MedGen UID:
452349
Concept ID:
C0266491
Finding
Heterotopia or neuronal heterotopia are macroscopic clusters of misplaced neurons (gray matter), most often situated along the ventricular walls or within the subcortical white matter.
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.
Cerebellar vermis hypoplasia
MedGen UID:
333548
Concept ID:
C1840379
Finding
Underdevelopment of the vermis of cerebellum.
Dilated fourth ventricle
MedGen UID:
376050
Concept ID:
C1847117
Finding
An abnormal dilatation of the fourth cerebral ventricle.
Cerebellar cyst
MedGen UID:
339835
Concept ID:
C1847762
Finding
Motor delay
MedGen UID:
381392
Concept ID:
C1854301
Finding
A type of Developmental delay characterized by a delay in acquiring motor skills.
Abnormal periventricular white matter morphology
MedGen UID:
435926
Concept ID:
C2673431
Finding
A structural abnormality of the myelinated axons (white matter) located near the cerebral ventricles.
Cerebellar dysplasia
MedGen UID:
479952
Concept ID:
C3278322
Finding
Cerebellar dysplasia (abnormal growth or development) is defined by abnormal cerebellar foliation, white matter arborization, and gray-white matter junction. Cerebellar dysplasia is a neuroimaging finding that describes abnormalities of both the cerebellar cortex and white matter and is associated with variable neurodevelopmental outcome. Dysplasia may globally involve the cerebellum or affect only one cerebellar hemisphere. In addition, cerebellar dysplasia may be associated with cortical/subcortical cysts.
Oculomotor apraxia
MedGen UID:
483686
Concept ID:
C3489733
Disease or Syndrome
Ocular motor apraxia is a deficiency in voluntary, horizontal, lateral, fast eye movements (saccades) with retention of slow pursuit movements. The inability to follow objects visually is often compensated by head movements. There may be decreased smooth pursuit, and cancellation of the vestibulo-ocular reflex.
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.
Generalized hypotonia
MedGen UID:
346841
Concept ID:
C1858120
Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Amblyopia
MedGen UID:
8009
Concept ID:
C0002418
Disease or Syndrome
Reduced visual acuity that is uncorrectable by lenses in the absence of detectable anatomic defects in the eye or visual pathways.
Myopia
MedGen UID:
44558
Concept ID:
C0027092
Disease or Syndrome
Nearsightedness, also known as myopia, is an eye condition that causes blurry distance vision. People who are nearsighted have more trouble seeing things that are far away (such as when driving) than things that are close up (such as when reading or using a computer). If it is not treated with corrective lenses or surgery, nearsightedness can lead to squinting, eyestrain, headaches, and significant visual impairment.\n\nNearsightedness usually begins in childhood or adolescence. It tends to worsen with age until adulthood, when it may stop getting worse (stabilize). In some people, nearsightedness improves in later adulthood.\n\nFor normal vision, light passes through the clear cornea at the front of the eye and is focused by the lens onto the surface of the retina, which is the lining of the back of the eye that contains light-sensing cells. People who are nearsighted typically have eyeballs that are too long from front to back. As a result, light entering the eye is focused too far forward, in front of the retina instead of on its surface. It is this change that causes distant objects to appear blurry. The longer the eyeball is, the farther forward light rays will be focused and the more severely nearsighted a person will be.\n\nNearsightedness is measured by how powerful a lens must be to correct it. The standard unit of lens power is called a diopter. Negative (minus) powered lenses are used to correct nearsightedness. The more severe a person's nearsightedness, the larger the number of diopters required for correction. In an individual with nearsightedness, one eye may be more nearsighted than the other.\n\nEye doctors often refer to nearsightedness less than -5 or -6 diopters as "common myopia." Nearsightedness of -6 diopters or more is commonly called "high myopia." This distinction is important because high myopia increases a person's risk of developing other eye problems that can lead to permanent vision loss or blindness. These problems include tearing and detachment of the retina, clouding of the lens (cataract), and an eye disease called glaucoma that is usually related to increased pressure within the eye. The risk of these other eye problems increases with the severity of the nearsightedness. The term "pathological myopia" is used to describe cases in which high myopia leads to tissue damage within the eye.
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.
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.
Retinal atrophy
MedGen UID:
101075
Concept ID:
C0521694
Disease or Syndrome
Well-demarcated area(s) of partial or complete depigmentation in the fundus, reflecting atrophy of the retinal pigment epithelium with associated retinal photoreceptor loss.
Retinal dystrophy
MedGen UID:
208903
Concept ID:
C0854723
Finding
Retinal dystrophy is an abnormality of the retina associated with a hereditary process. Retinal dystrophies are defined by their predominantly monogenic inheritance and they are frequently associated with loss or dysfunction of photoreceptor cells as a primary or secondary event.
Retinal thinning
MedGen UID:
762617
Concept ID:
C3549703
Finding
Reduced anteroposterior thickness of the retina. This phenotype can be appreciated by retinal optical coherence tomography (OCT).

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVAtaxia - intellectual disability - oculomotor apraxia - cerebellar cysts syndrome

Professional guidelines

PubMed

Spahiu L, Behluli E, Grajçevci-Uka V, Liehr T, Temaj G
J Mother Child 2022 Mar 1;26(1):118-123. Epub 2023 Feb 22 doi: 10.34763/jmotherandchild.20222601.d-22-00034. PMID: 36803942Free PMC Article

Recent clinical studies

Diagnosis

Geerts C, Sznajer Y, D'haenens E, Dumitriu D, Nassogne MC
Eur J Med Genet 2023 Feb;66(2):104692. Epub 2022 Dec 31 doi: 10.1016/j.ejmg.2022.104692. PMID: 36592689
Spahiu L, Behluli E, Grajçevci-Uka V, Liehr T, Temaj G
J Mother Child 2022 Mar 1;26(1):118-123. Epub 2023 Feb 22 doi: 10.34763/jmotherandchild.20222601.d-22-00034. PMID: 36803942Free PMC Article

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