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Sulfite oxidase deficiency due to molybdenum cofactor deficiency type B(MOCODB)

MedGen UID:
340760
Concept ID:
C1854989
Disease or Syndrome
Synonyms: Molybdenum cofactor deficiency B; Molybdenum cofactor deficiency, complementation group B
SNOMED CT: Molybdenum cofactor deficiency complementation group B (1003368009)
 
Gene (location): MOCS2 (5q11.2)
 
Monarch Initiative: MONDO:0009644
OMIM®: 252160
Orphanet: ORPHA308393

Disease characteristics

Excerpted from the GeneReview: Molybdenum Cofactor Deficiency
Molybdenum cofactor deficiency (MoCD) represents a spectrum, with some individuals experiencing significant signs and symptoms in the neonatal period and early infancy (termed early-onset or severe MoCD) and others developing signs and symptoms in childhood or adulthood (termed late-onset or mild MoCD). Individuals with early-onset MoCD typically present in the first days of life with severe encephalopathy, including refractory seizures, opisthotonos, axial and appendicular hypotonia, feeding difficulties, and apnea. Head imaging may demonstrate loss of gray and white matter differentiation, gyral swelling, sulci injury (typically assessed by evaluating the depth of focal lesional injury within the sulci), diffusely elevated T2-weighted signal, and panlobar diffusion restriction throughout the forebrain and midbrain with relative sparring of the brain stem. Prognosis for early-onset MoCD is poor, with about 75% succumbing in infancy to secondary complications of their neurologic disability (i.e., pneumonia). Late-onset MoCD is typically characterized by milder symptoms, such as acute neurologic decompensation in the setting of infection. Episodes vary in nature but commonly consist of altered mental status, dystonia, choreoathetosis, ataxia, nystagmus, and fluctuating hypotonia and hypertonia. These features may improve after resolution of the inciting infection or progress in a gradual or stochastic manner over the lifetime. Brain imaging may be normal or may demonstrate T2-weighted hyperintense or cystic lesions in the globus pallidus, thinning of the corpus callosum, and cerebellar atrophy. [from GeneReviews]
Authors:
Albert Misko  |  Karishma Mahtani  |  Jessica Abbott, et. al.   view full author information

Additional descriptions

From OMIM
Molybdenum cofactor deficiency is a rare autosomal recessive metabolic disorder characterized by neonatal onset of intractable seizures, opisthotonus, and facial dysmorphism associated with hypouricemia and elevated urinary sulfite levels. Affected individuals show severe neurologic damage and often die in early childhood (summary by Reiss et al., 1999). For a general phenotypic description and a discussion of genetic heterogeneity of MOCOD, see MOCODA (252150), which is clinically indistinguishable from MOCODB.  http://www.omim.org/entry/252160
From MedlinePlus Genetics
Molybdenum cofactor deficiency is a rare condition characterized by brain dysfunction (encephalopathy) that worsens over time. Babies with this condition appear normal at birth, but within a week they have difficulty feeding and develop seizures that do not improve with treatment (intractable seizures). Brain abnormalities, including deterioration (atrophy) of brain tissue, lead to severe developmental delay; affected individuals usually do not learn to sit unassisted or to speak. A small percentage of affected individuals have an exaggerated startle reaction (hyperekplexia) to unexpected stimuli such as loud noises. Other features of molybdenum cofactor deficiency can include a small head size (microcephaly) and facial features that are described as "coarse."

Because of the serious health problems caused by molybdenum cofactor deficiency, affected individuals usually do not survive past early childhood.

Tests reveal that affected individuals have high levels of chemicals called sulfite, S-sulfocysteine, xanthine, and hypoxanthine in the urine and low levels of a chemical called uric acid in the blood.  https://medlineplus.gov/genetics/condition/molybdenum-cofactor-deficiency

Clinical features

From HPO
Xanthinuria
MedGen UID:
450997
Concept ID:
C0220988
Disease or Syndrome
An increased concentration of xanthine in the urine.
Xanthine nephrolithiasis
MedGen UID:
376358
Concept ID:
C1848431
Finding
The presence of xanthine-containing calculi (stones) in the kidneys.
Increased urinary sulfite level
MedGen UID:
338580
Concept ID:
C1848957
Finding
Increased concentration of SO3(2-), i.e., sulfite, in the urine.
Increased urinary taurine
MedGen UID:
812777
Concept ID:
C3806447
Finding
Increased concentration of taurine in the urine.
Increased urinary hypoxanthine level
MedGen UID:
816817
Concept ID:
C3810487
Finding
An increased level of hypoxanthine in the urine.
Decreased urinary urate
MedGen UID:
868715
Concept ID:
C4023118
Finding
Decreased concentration of urate in the urine.
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.
Gliosis
MedGen UID:
4899
Concept ID:
C0017639
Pathologic Function
Gliosis is the focal proliferation of glial cells in the central nervous system.
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.
Opisthotonus
MedGen UID:
56246
Concept ID:
C0151818
Sign or Symptom
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
Hypoplasia of the corpus callosum
MedGen UID:
138005
Concept ID:
C0344482
Congenital Abnormality
Underdevelopment of the corpus callosum.
Spastic tetraplegia
MedGen UID:
98433
Concept ID:
C0426970
Disease or Syndrome
Spastic paralysis affecting all four limbs.
Bilateral tonic-clonic seizure
MedGen UID:
141670
Concept ID:
C0494475
Sign or Symptom
A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase.
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.
Diffuse cerebral atrophy
MedGen UID:
108958
Concept ID:
C0598275
Finding
Diffuse unlocalised atrophy affecting the cerebrum.
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.
Axonal loss
MedGen UID:
316962
Concept ID:
C1832338
Finding
A reduction in the number of axons in the peripheral nervous system.
Irritability
MedGen UID:
397841
Concept ID:
C2700617
Mental Process
A proneness to anger, i.e., a condition of being easily bothered or annoyed.
Ventriculomegaly
MedGen UID:
480553
Concept ID:
C3278923
Finding
An increase in size of the ventricular system of the brain.
Myoclonic spasms
MedGen UID:
812772
Concept ID:
C3806442
Finding
Thin corpus callosum
MedGen UID:
1785336
Concept ID:
C5441562
Anatomical Abnormality
An abnormally thin corpus callous, due to atrophy, hypoplasia or agenesis. This term is intended to be used in situations where it is not known if thinning of the corpus callosum (for instance, as visualized by magnetic resonance tomography) is due to abnormal development (e.g. a leukodystrophy) or atrophy following normal development (e.g. neurodegeneration).
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.
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.
Frontal bossing
MedGen UID:
67453
Concept ID:
C0221354
Congenital Abnormality
Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline.
Macrocephaly
MedGen UID:
745757
Concept ID:
C2243051
Finding
Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Hypouricemia
MedGen UID:
113163
Concept ID:
C0221333
Finding
An abnormally low level of uric acid in the blood.
Combined molybdoflavoprotein enzyme deficiency
MedGen UID:
75652
Concept ID:
C0268119
Disease or Syndrome
Molybdenum cofactor deficiency (MoCD) represents a spectrum, with some individuals experiencing significant signs and symptoms in the neonatal period and early infancy (termed early-onset or severe MoCD) and others developing signs and symptoms in childhood or adulthood (termed late-onset or mild MoCD). Individuals with early-onset MoCD typically present in the first days of life with severe encephalopathy, including refractory seizures, opisthotonos, axial and appendicular hypotonia, feeding difficulties, and apnea. Head imaging may demonstrate loss of gray and white matter differentiation, gyral swelling, sulci injury (typically assessed by evaluating the depth of focal lesional injury within the sulci), diffusely elevated T2-weighted signal, and panlobar diffusion restriction throughout the forebrain and midbrain with relative sparring of the brain stem. Prognosis for early-onset MoCD is poor, with about 75% succumbing in infancy to secondary complications of their neurologic disability (i.e., pneumonia). Late-onset MoCD is typically characterized by milder symptoms, such as acute neurologic decompensation in the setting of infection. Episodes vary in nature but commonly consist of altered mental status, dystonia, choreoathetosis, ataxia, nystagmus, and fluctuating hypotonia and hypertonia. These features may improve after resolution of the inciting infection or progress in a gradual or stochastic manner over the lifetime. Brain imaging may be normal or may demonstrate T2-weighted hyperintense or cystic lesions in the globus pallidus, thinning of the corpus callosum, and cerebellar atrophy.
Long face
MedGen UID:
324419
Concept ID:
C1836047
Finding
Facial height (length) is more than 2 standard deviations above the mean (objective); or, an apparent increase in the height (length) of the face (subjective).
Thick vermilion border
MedGen UID:
332232
Concept ID:
C1836543
Finding
Increased width of the skin of vermilion border region of upper lip.
Short nose
MedGen UID:
343052
Concept ID:
C1854114
Finding
Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip.
Long philtrum
MedGen UID:
351278
Concept ID:
C1865014
Finding
Distance between nasal base and midline upper lip vermilion border more than 2 SD above the mean. Alternatively, an apparently increased distance between nasal base and midline upper lip vermilion border.
Full cheeks
MedGen UID:
355661
Concept ID:
C1866231
Finding
Increased prominence or roundness of soft tissues between zygomata and mandible.
Ectopia lentis
MedGen UID:
41704
Concept ID:
C0013581
Congenital Abnormality
Dislocation or malposition of the crystalline lens of the eye. A partial displacement (or dislocation) of the lens is described as a subluxation of the lens, while a complete displacement is termed luxation of the lens. A complete displacement occurs if the lens is completely outside the patellar fossa of the lens, either in the anterior chamber, in the vitreous, or directly on the retina. If the lens is partially displaced but still contained within the lens space, then it is termed subluxation.
Hypertelorism
MedGen UID:
9373
Concept ID:
C0020534
Finding
Although hypertelorism means an excessive distance between any paired organs (e.g., the nipples), the use of the word has come to be confined to ocular hypertelorism. Hypertelorism occurs as an isolated feature and is also a feature of many syndromes, e.g., Opitz G syndrome (see 300000), Greig cephalopolysyndactyly (175700), and Noonan syndrome (163950) (summary by Cohen et al., 1995).
Lens luxation
MedGen UID:
6043
Concept ID:
C0023309
Injury or Poisoning
Complete dislocation of the lens of 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.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
Follow this link to review classifications for Sulfite oxidase deficiency due to molybdenum cofactor deficiency type B in Orphanet.

Recent clinical studies

Etiology

Enemark JH
J Inorg Biochem 2023 Oct;247:112312. Epub 2023 Jul 4 doi: 10.1016/j.jinorgbio.2023.112312. PMID: 37441922
Spiegel R, Schwahn BC, Squires L, Confer N
J Inherit Metab Dis 2022 May;45(3):456-469. Epub 2022 Mar 3 doi: 10.1002/jimd.12488. PMID: 35192225Free PMC Article

Diagnosis

Spiegel R, Schwahn BC, Squires L, Confer N
J Inherit Metab Dis 2022 May;45(3):456-469. Epub 2022 Mar 3 doi: 10.1002/jimd.12488. PMID: 35192225Free PMC Article
Reiss J, Hahnewald R
Hum Mutat 2011 Jan;32(1):10-8. doi: 10.1002/humu.21390. PMID: 21031595

Prognosis

Spiegel R, Schwahn BC, Squires L, Confer N
J Inherit Metab Dis 2022 May;45(3):456-469. Epub 2022 Mar 3 doi: 10.1002/jimd.12488. PMID: 35192225Free PMC Article

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