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Pontocerebellar hypoplasia type 1B(PCH1B)

MedGen UID:
766363
Concept ID:
C3553449
Disease or Syndrome
Synonyms: PCH1B; PONTOCEREBELLAR HYPOPLASIA, TYPE 1B
 
Gene (location): EXOSC3 (9p13.2)
 
Monarch Initiative: MONDO:0013853
OMIM®: 614678

Disease characteristics

Excerpted from the GeneReview: EXOSC3 Pontocerebellar Hypoplasia
EXOSC3 pontocerebellar hypoplasia (EXOSC3-PCH) is characterized by abnormalities in the posterior fossa and degeneration of the anterior horn cells. At birth, skeletal muscle weakness manifests as hypotonia (sometimes with congenital joint contractures) and poor feeding. In persons with prolonged survival, spasticity, dystonia, and seizures become evident. Within the first year of life respiratory insufficiency and swallowing difficulties are common. Intellectual disability is severe. Life expectancy ranges from a few weeks to adolescence. To date, 82 individuals (from 58 families) with EXOSC3-PCH have been described. [from GeneReviews]
Authors:
Frank Baas  |  Tessa van Dijk   view full author information

Additional description

From OMIM
Pontocerebellar hypoplasia type 1B is a severe autosomal recessive neurologic disorder characterized by a combination of cerebellar and spinal motor neuron degeneration beginning at birth. There is diffuse muscle weakness, progressive microcephaly, global developmental delay, and brainstem involvement (summary by Wan et al., 2012). PCH1B can be divided into mild, moderate, and severe subgroups that vary in age at onset, progression, clinical and neuroradiologic severity, and survival (summary by Halevy et al., 2014). For a phenotypic description and a discussion of genetic heterogeneity of PCH, see PCH1A (607596).  http://www.omim.org/entry/614678

Clinical features

From HPO
Abnormal foot morphology
MedGen UID:
1762829
Concept ID:
C5399834
Anatomical Abnormality
An abnormality of the skeleton of foot.
Growth delay
MedGen UID:
99124
Concept ID:
C0456070
Pathologic Function
A deficiency or slowing down of growth pre- and postnatally.
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.
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.
Seizure
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterised 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.
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.
Cerebellar cyst
MedGen UID:
339835
Concept ID:
C1847762
Finding
Absent speech
MedGen UID:
340737
Concept ID:
C1854882
Finding
Complete lack of development of speech and language abilities.
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.
Hip dislocation
MedGen UID:
42455
Concept ID:
C0019554
Injury or Poisoning
Displacement of the femur from its normal location in the hip joint.
Muscle weakness
MedGen UID:
57735
Concept ID:
C0151786
Finding
Reduced strength of muscles.
Flexion contracture
MedGen UID:
83069
Concept ID:
C0333068
Anatomical Abnormality
A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints.
Muscular atrophy
MedGen UID:
892680
Concept ID:
C0541794
Pathologic Function
The presence of skeletal muscular atrophy (which is also known as amyotrophy).
Poor head control
MedGen UID:
322809
Concept ID:
C1836038
Finding
Difficulty to maintain correct position of the head while standing or sitting.
Progressive microcephaly
MedGen UID:
340542
Concept ID:
C1850456
Anatomical Abnormality
Progressive microcephaly is diagnosed when the head circumference falls progressively behind age- and gender-dependent norms.
Axial hypotonia
MedGen UID:
342959
Concept ID:
C1853743
Finding
Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.
Generalized hypotonia
MedGen UID:
346841
Concept ID:
C1858120
Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Respiratory insufficiency
MedGen UID:
11197
Concept ID:
C0035229
Pathologic Function
Impairment of gas exchange within the lungs secondary to a disease process, neoplasm, or trauma, possibly resulting in hypoxia, hypercarbia, or both, but not requiring intubation or mechanical ventilation. Patients are normally managed with pharmaceutical therapy, supplemental oxygen, or both.
Tongue fasciculations
MedGen UID:
65987
Concept ID:
C0239548
Finding
Fasciculations or fibrillation affecting the tongue muscle.
Tongue atrophy
MedGen UID:
66828
Concept ID:
C0241423
Finding
Wasting of the tongue.
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 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.

Recent clinical studies

Diagnosis

Mu W, Heller T, Barañano KW
BMJ Case Rep 2021 Jan 18;14(1) doi: 10.1136/bcr-2020-236732. PMID: 33462000Free PMC Article

Clinical prediction guides

François-Moutal L, Jahanbakhsh S, Nelson ADL, Ray D, Scott DD, Hennefarth MR, Moutal A, Perez-Miller S, Ambrose AJ, Al-Shamari A, Coursodon P, Meechoovet B, Reiman R, Lyons E, Beilstein M, Chapman E, Morris QD, Van Keuren-Jensen K, Hughes TR, Khanna R, Koehler C, Jen J, Gokhale V, Khanna M
ACS Chem Biol 2018 Oct 19;13(10):3000-3010. Epub 2018 Sep 6 doi: 10.1021/acschembio.8b00745. PMID: 30141626Free PMC Article

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