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Condition report · Metabolic

Refsum Disease and Peroxisomal Disorders

Inherited disorders of single enzymes in peroxisomes, cell structures that break down certain fats, including adult Refsum disease, D-bifunctional protein deficiency and rhizomelic chondrodysplasia punctata types 2 and 3. Adult Refsum disease is treatable with diet.

A condition report looks for rare variants known to cause the conditions it covers.

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The 6 conditions we analyse

Adult Refsum Disease

Autosomal recessive

Caused by variants in PHYH or PEX7, which lead to a build-up of phytanic acid and cause night blindness and retinitis pigmentosa, loss of smell, nerve damage and sometimes heart rhythm problems.

What a diagnosis changes

Knowing allows a diet low in phytanic acid, which can halt progression of nerve and eye damage.

Genes analysed

Also known as

ARD; disorder of cornification 11 (phytanic acid type); DOC 11 (phytanic acid type); heredopathia atactica polyneuritiformis; HMSN 4; HMSN type IV; HSMN IV; hypertrophic neuropathy of Refsum; phytanic acid oxidase deficiency; RDPA; Refsum Disease; Refsum disease with increased pipecolic acidemia; Refsum's disease

Includes 2 related subtypes ↓
  • adult Refsum disease due to PEX7 defect
  • Refsum disease, classic
MONDO:0009958Orphanet 773MedGen 11161

D-Bifunctional Protein Deficiency

Autosomal recessive

Caused by variants in HSD17B4, which usually causes severe low muscle tone and seizures in infancy, while milder forms can cause hearing loss and ovarian failure (Perrault syndrome).

What a diagnosis changes

Knowing can end a diagnostic search and guide supportive care and family planning.

Genes analysed

Also known as

17-beta-hydroxysteroid dehydrogenase IV deficiency; bifunctional enzyme deficiency; D-bifunctional enzyme deficiency; HSD17B4 deficiency; multifunctional enzyme deficiency; peroxisomal multifunctional enzyme (MFE2) deficiency; peroxisomal multifunctional enzyme deficiency; pseudo-Zellweger syndrome

MONDO:0009855OMIM 261515Orphanet 300MedGen 137982

Peroxisomal Acyl-CoA Oxidase Deficiency

Autosomal recessive

Caused by variants in ACOX1, which can cause low muscle tone, seizures and progressive loss of skills in early childhood.

What a diagnosis changes

Knowing can end a diagnostic search and guide supportive care and family planning.

Genes analysed

Also known as

ACOX1 deficiency; pseudo-NALD; pseudo-neonatal adrenoleukodystrophy; Pseudoadrenoleukodystrophy

MONDO:0009919OMIM 264470Orphanet 2971MedGen 376636

Alpha-Methylacyl-CoA Racemase Deficiency

Autosomal recessive

Caused by variants in AMACR, which can cause adult-onset nerve damage, vision problems and seizures, or a bile acid synthesis defect in infancy.

What a diagnosis changes

Knowing allows a diet low in phytanic and pristanic acid, which may slow progression.

Genes analysed

Also known as

AMACR; AMACR deficiency; AMACRD

Includes 1 related subtype ↓
  • congenital bile acid synthesis defect 4
MONDO:0013681OMIM 614307MedGen 482058

Glyceronephosphate O-Acyltransferase Deficiency

Autosomal recessive

Caused by variants in GNPAT, which impairs plasmalogen production and causes rhizomelic chondrodysplasia punctata type 2, with shortened limbs, cataracts and developmental delay.

What a diagnosis changes

Knowing can end a diagnostic search and guide supportive care and family planning.

Genes analysed

Also known as

GNPAT deficiency

Includes 1 related subtype ↓
  • rhizomelic chondrodysplasia punctata type 2
MONDO:0100273

Alkylglycerone-Phosphate Synthase Deficiency

Autosomal recessive

Caused by variants in AGPS, which impairs plasmalogen production and causes rhizomelic chondrodysplasia punctata type 3.

What a diagnosis changes

Knowing can end a diagnostic search and guide supportive care and family planning.

Genes analysed

Also known as

AGPS deficiency

Includes 1 related subtype ↓
  • rhizomelic chondrodysplasia punctata type 3
MONDO:0100274

Other metabolic conditions

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