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Peroxisome biogenesis disorder 9B(PBD9B)

MedGen UID:
440765
Concept ID:
C2749346
Disease or Syndrome
Synonyms: PEROXISOME BIOGENESIS DISORDER, PEX7-RELATED, ATYPICAL; Refsum disease, adult, 2
 
Gene (location): PEX7 (6q23.3)
 
Monarch Initiative: MONDO:0013945
OMIM®: 614879

Disease characteristics

Excerpted from the GeneReview: Adult Refsum Disease
Adult Refsum disease (ARD is associated with elevated plasma phytanic acid levels, late childhood-onset (or later) retinitis pigmentosa, and variable combinations of anosmia, polyneuropathy, deafness, ataxia, and ichthyosis. Onset of symptoms ranges from age seven months to older than age 50 years. Cardiac arrhythmia and heart failure caused by cardiomyopathy are potentially severe health problems that develop later in life. [from GeneReviews]
Authors:
Hans R Waterham  |  Ronald JA Wanders  |  Bart P Leroy   view full author information

Additional description

From OMIM
While most patients of PBD complementation group 11 manifest rhizomelic chondrodysplasia punctata (RCDP1; 215100), a few have been reported with unusually mild phenotypes with longer survival, less neurologic involvement, normal or near-normal growth, and absence of rhizomelia (Braverman et al., 2002). In some cases this phenotype was indistinguishable from that of classic Refsum disease (266500) and patients carried this diagnosis. Individuals with PBDs of complementation group 11 (CG11, equivalent to CGR) have mutations in the PEX7 gene. For information on the history of PBD complementation groups, see 214100.  http://www.omim.org/entry/614879

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).
Cardiomyopathy
MedGen UID:
209232
Concept ID:
C0878544
Disease or Syndrome
A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.
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.
Anosmia
MedGen UID:
1950
Concept ID:
C0003126
Finding
An inability to perceive odors. This is a general term describing inability to smell arising in any part of the process of smelling from absorption of odorants into the nasal mucous overlying the olfactory epithelium, diffusion to the cilia, binding to olfactory receptor sites, generation of action potentials in olfactory neurons, and perception of a smell.
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).
Polyneuropathy
MedGen UID:
57502
Concept ID:
C0152025
Disease or Syndrome
A generalized disorder of peripheral nerves.
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.
Total anosmia
MedGen UID:
869342
Concept ID:
C4023768
Finding
Inability to detect any qualitative olfactory sensation.
Muscle weakness
MedGen UID:
57735
Concept ID:
C0151786
Finding
Reduced strength of muscles.
Distal muscle weakness
MedGen UID:
140883
Concept ID:
C0427065
Finding
Reduced strength of the musculature of the distal extremities.
Elevated circulating phytanic acid concentration
MedGen UID:
869360
Concept ID:
C4023786
Finding
An abnormal elevation of phytanic acid.
Ichthyosis
MedGen UID:
7002
Concept ID:
C0020757
Disease or Syndrome
An abnormality of the skin characterized the presence of excessive amounts of dry surface scales on the skin resulting from an abnormality of keratinization.
Night blindness
MedGen UID:
10349
Concept ID:
C0028077
Disease or Syndrome
Inability to see well at night or in poor light.
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.
Reduced visual acuity
MedGen UID:
65889
Concept ID:
C0234632
Finding
Diminished clarity of vision.
Constriction of peripheral visual field
MedGen UID:
68613
Concept ID:
C0235095
Finding
An absolute or relative decrease in retinal sensitivity extending from edge (periphery) of the visual field in a concentric pattern. The visual field is the area that is perceived simultaneously by a fixating eye.
Rod-cone dystrophy
MedGen UID:
1632921
Concept ID:
C4551714
Disease or Syndrome
An inherited retinal disease subtype in which the rod photoreceptors appear to be more severely affected than the cone photoreceptors. Typical presentation is with nyctalopia (due to rod dysfunction) followed by loss of mid-peripheral field of vision, which gradually extends and leaves many patients with a small central island of vision due to the preservation of macular cones.

Recent clinical studies

Etiology

Masih S, Moirangthem A, Phadke SR
Am J Med Genet A 2021 May;185(5):1504-1508. Epub 2021 Feb 14 doi: 10.1002/ajmg.a.62110. PMID: 33586206

Diagnosis

Masih S, Moirangthem A, Phadke SR
Am J Med Genet A 2021 May;185(5):1504-1508. Epub 2021 Feb 14 doi: 10.1002/ajmg.a.62110. PMID: 33586206

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