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Brown-Vialetto-van Laere syndrome 2(BVVLS2; RTD2)

MedGen UID:
766452
Concept ID:
C3553538
Disease or Syndrome
Synonym: Riboflavin transporter deficiency type 2
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): SLC52A2 (8q24.3)
 
Monarch Initiative: MONDO:0013867
OMIM®: 614707
Orphanet: ORPHA572550

Definition

Brown-Vialetto-Van Laere syndrome-2 (BVVLS2) is an autosomal recessive progressive neurologic disorder characterized by early childhood onset of sensorineural deafness, bulbar dysfunction, and severe diffuse muscle weakness and wasting of the upper and lower limbs and axial muscles, resulting in respiratory insufficiency. Some patients may lose independent ambulation. Because it results from a defect in riboflavin metabolism, some patients may benefit from high-dose riboflavin supplementation (summary by Johnson et al., 2012; Foley et al., 2014). For discussion of genetic heterogeneity of Brown-Vialetto-Van Laere syndrome, see BVVLS1 (211530). [from OMIM]

Clinical features

From HPO
Inborn organic aciduria
MedGen UID:
66037
Concept ID:
C0241775
Finding
Excretion of non-amino organic acids in urine.
Limb muscle weakness
MedGen UID:
107956
Concept ID:
C0587246
Finding
Reduced strength and weakness of the muscles of the arms and legs.
Split hand
MedGen UID:
397570
Concept ID:
C2699510
Congenital Abnormality
A condition in which middle parts of the hand (fingers and metacarpals) are missing giving a cleft appearance. The severity is very variable ranging from slightly hypoplastic middle fingers over absent middel fingers as far as oligo- or monodactyl hands.
Dysphagia
MedGen UID:
41440
Concept ID:
C0011168
Disease or Syndrome
Difficulty in swallowing.
Sensorineural hearing loss disorder
MedGen UID:
9164
Concept ID:
C0018784
Disease or Syndrome
A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.
Aggressive behavior
MedGen UID:
1375
Concept ID:
C0001807
Individual Behavior
Behavior or an act aimed at harming a person, animal, or physical property (e.g., acts of physical violence; shouting, swearing, and using harsh language; slashing someone's tires).
Cerebellar ataxia
MedGen UID:
849
Concept ID:
C0007758
Disease or Syndrome
Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).
Hypokinesia
MedGen UID:
39223
Concept ID:
C0086439
Finding
Abnormally diminished motor activity. In contrast to paralysis, hypokinesia is not characterized by a lack of motor strength, but rather by a poverty of movement. The typical habitual movements (e.g., folding the arms, crossing the legs) are reduced in frequency.
Cranial nerve paralysis
MedGen UID:
57717
Concept ID:
C0151311
Disease or Syndrome
Injury to any of the cranial nerves or their nuclei in the brain resulting in muscle weakness.
Clumsiness
MedGen UID:
66690
Concept ID:
C0233844
Sign or Symptom
Lack of physical coordination resulting in an abnormal tendency to drop items or bump into objects.
Areflexia
MedGen UID:
115943
Concept ID:
C0234146
Finding
Absence of neurologic reflexes such as the knee-jerk reaction.
Sensorimotor neuropathy
MedGen UID:
207266
Concept ID:
C1112256
Disease or Syndrome
Bulbar palsy
MedGen UID:
898626
Concept ID:
C4082299
Disease or Syndrome
Bulbar weakness (or bulbar palsy) refers to bilateral impairment of function of the lower cranial nerves IX, X, XI and XII, which occurs due to lower motor neuron lesion either at nuclear or fascicular level in the medulla or from bilateral lesions of the lower cranial nerves outside the brain-stem. Bulbar weakness is often associated with difficulty in chewing, weakness of the facial muscles, dysarthria, palatal weakness and regurgitation of fluids, dysphagia, and dysphonia.
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.
Neck muscle weakness
MedGen UID:
66808
Concept ID:
C0240479
Finding
Decreased strength of the neck musculature.
Facial palsy
MedGen UID:
87660
Concept ID:
C0376175
Disease or Syndrome
Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form.
Kyphoscoliosis
MedGen UID:
154361
Concept ID:
C0575158
Anatomical Abnormality
An abnormal curvature of the spine in both a coronal (lateral) and sagittal (back-to-front) plane.
Generalized amyotrophy
MedGen UID:
234650
Concept ID:
C1389113
Disease or Syndrome
Generalized (diffuse, unlocalized) amyotrophy (muscle atrophy) affecting multiple muscles.
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.
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.
Visual loss
MedGen UID:
784038
Concept ID:
C3665386
Finding
Loss of visual acuity (implying that vision was better at a certain time point in life). Otherwise the term reduced visual acuity should be used (or a subclass of that).

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVBrown-Vialetto-van Laere syndrome 2

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