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Peroxisome biogenesis disorder 8B(PBD8B)

MedGen UID:
766874
Concept ID:
C3553960
Disease or Syndrome
Synonym: PBD8B
 
Gene (location): PEX16 (11p11.2)
 
Monarch Initiative: MONDO:0013943
OMIM®: 614877

Definition

The overlapping phenotypes of neonatal adrenoleukodystrophy (NALD) and infantile Refsum disease (IRD) represent the milder manifestations of the Zellweger syndrome spectrum (ZSS) of peroxisome biogenesis disorders. The clinical course of patients with the NALD and IRD presentation is variable and may include developmental delay, hypotonia, liver dysfunction, sensorineural hearing loss, retinal dystrophy, and visual impairment. Children with the NALD presentation may reach their teens, and those with the IRD presentation may reach adulthood (summary by Waterham and Ebberink, 2012). For a complete phenotypic description and a discussion of genetic heterogeneity of PBD(NALD/IRD), see 601539. Individuals with mutations in the PEX16 gene have cells of complementation group 9 (CG9, equivalent to CGD). For information on the history of PBD complementation groups, see 214100. [from OMIM]

Clinical features

From HPO
Ankle clonus
MedGen UID:
68672
Concept ID:
C0238651
Finding
Clonus is an involuntary tendon reflex that causes repeated flexion and extension of the foot. Ankle clonus is tested by rapidly flexing the foot upward.
Failure to thrive
MedGen UID:
746019
Concept ID:
C2315100
Disease or Syndrome
Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.
Constipation
MedGen UID:
1101
Concept ID:
C0009806
Sign or Symptom
Infrequent or difficult evacuation of feces.
Dysphagia
MedGen UID:
41440
Concept ID:
C0011168
Disease or Syndrome
Difficulty in swallowing.
Decreased liver function
MedGen UID:
65430
Concept ID:
C0232744
Finding
Reduced ability of the liver to perform its functions.
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).
Clonus
MedGen UID:
40341
Concept ID:
C0009024
Sign or Symptom
A series of rhythmic and involuntary muscle contractions (at a frequency of about 5 to 7 Hz) that occur in response to an abruptly applied and sustained stretch.
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.
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.
Peripheral neuropathy
MedGen UID:
18386
Concept ID:
C0031117
Disease or Syndrome
Peripheral neuropathy is a general term for any disorder of the peripheral nervous system. The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course.
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.
Spastic paraparesis
MedGen UID:
52432
Concept ID:
C0037771
Sign or Symptom
Mild or moderate loss of motor function accompanied by spasticity in the lower extremities. This condition is a manifestation of CENTRAL NERVOUS SYSTEM DISEASES that cause injury to the motor cortex or descending motor pathways.
Unsteady gait
MedGen UID:
68544
Concept ID:
C0231686
Finding
A shaky or wobbly manner of walking.
Dysmetria
MedGen UID:
68583
Concept ID:
C0234162
Finding
A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements.
Limb tremor
MedGen UID:
115980
Concept ID:
C0235081
Sign or Symptom
Dysesthesia
MedGen UID:
97901
Concept ID:
C0392699
Finding
Painful sensations elicited by a nonpainful cutaneous stimulus such as a light touch or gentle stroking over affected areas of the body. Sometimes referred to as hyperpathia or hyperalgesia. Often perceived as an intense burning, dyesthesias may outlast the stimulus by several seconds.
Tip-toe gait
MedGen UID:
98104
Concept ID:
C0427144
Finding
An abnormal gait pattern characterized by the failure of the heel to contact the floor at the onset of stance during gait.
Corpus callosum atrophy
MedGen UID:
96560
Concept ID:
C0431370
Finding
The presence of atrophy (wasting) of the corpus callosum.
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 vermis atrophy
MedGen UID:
149271
Concept ID:
C0742028
Disease or Syndrome
Wasting (atrophy) of the vermis of cerebellum.
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.
Peripheral demyelination
MedGen UID:
451074
Concept ID:
C0878575
Pathologic Function
A loss of myelin from the internode regions along myelinated nerve fibers of the peripheral nervous system.
Abnormal cerebral white matter morphology
MedGen UID:
181756
Concept ID:
C0948163
Pathologic Function
An abnormality of the cerebral white matter.
Lower limb spasticity
MedGen UID:
220865
Concept ID:
C1271100
Finding
Spasticity (velocity-dependent increase in tonic stretch reflexes with increased muscle tone and hyperexcitable tendon reflexes) in the muscles of the lower limbs, hips, and pelvis.
Loss of ambulation
MedGen UID:
332305
Concept ID:
C1836843
Finding
Inability to walk in a person who previous had the ability to walk.
Brisk reflexes
MedGen UID:
382164
Concept ID:
C2673700
Finding
Tendon reflexes that are noticeably more active than usual (conventionally denoted 3+ on clinical examination). Brisk reflexes may or may not indicate a neurological lesion. They are distinguished from hyperreflexia by the fact that hyerreflexia is characterized by hyperactive repeating (clonic) reflexes, which are considered to be always abnormal.
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.
Brain atrophy
MedGen UID:
1643639
Concept ID:
C4551584
Disease or Syndrome
Partial or complete wasting (loss) of brain tissue that was once present.
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.
Rigidity
MedGen UID:
7752
Concept ID:
C0026837
Sign or Symptom
Continuous involuntary sustained muscle contraction. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from muscle spasticity.
Frequent falls
MedGen UID:
163408
Concept ID:
C0850703
Finding
Neonatal hypotonia
MedGen UID:
412209
Concept ID:
C2267233
Disease or Syndrome
Muscular hypotonia (abnormally low muscle tone) manifesting in the neonatal period.
Very long chain fatty acid accumulation
MedGen UID:
481027
Concept ID:
C3279397
Finding
Elevated circulating phytanic acid concentration
MedGen UID:
869360
Concept ID:
C4023786
Finding
An abnormal elevation of phytanic acid.
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.
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.
Horizontal nystagmus
MedGen UID:
124399
Concept ID:
C0271385
Disease or Syndrome
Nystagmus consisting of horizontal to-and-fro eye movements.
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.
Visual impairment
MedGen UID:
777085
Concept ID:
C3665347
Finding
Visual impairment (or vision impairment) is vision loss (of a person) to such a degree as to qualify as an additional support need through a significant limitation of visual capability resulting from either disease, trauma, or congenital or degenerative conditions that cannot be corrected by conventional means, such as refractive correction, medication, or surgery.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVPeroxisome biogenesis disorder 8B

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