237 articles
Blue diaper syndrome
Blue diaper syndrome, also called Drummond syndrome, is a rare metabolic disorder present from birth in which poor tryptophan absorption causes diarrhea and blue-stained diapers.
CADDS
CADDS (contiguous ABCD1 DXS1357E deletion syndrome) is a rare X-linked recessive neonatal disorder from deletion of ABCD1 and BCAP31 on Xq28, causing cholestasis, hypotonia, elevated VLCFA, and death before age one.
Carnosinaemia
Carnosinase deficiency (carnosinemia, CNDP1/CN1 deficiency, OMIM 212200): ultra-rare autosomal recessive metabolic disorder with low serum carnosinase, carnosinuria, and carnosinemia; variable neurological phenotype, causality debated.
Cerebrotendinous xanthomatosis
Cerebrotendinous xanthomatosis (CTX, cerebral cholesterinosis, MIM 213700) is a rare autosomal recessive CYP27A1 lipid-storage disorder causing cholestanol deposition, diarrhea, cataracts, xanthomas, and neurological decline; treated with chenodeoxycholic acid (Ctexli, FDA-approved 2025).
Chronic diarrhea with villous atrophy
Chronic diarrhea with villous atrophy (ORPHA:1670, OMIM 520100) is a rare mitochondrial genetic disease of infancy: early-onset chronic diarrhea, vomiting, lactic acidosis, renal and hepatic involvement, partial villous atrophy on biopsy, later neurologic and retinal complications.
Chronic neurovisceral acid sphingomyelinase deficiency
Chronic neurovisceral ASMD (Niemann-Pick disease type A/B, ORPHA:618891) is an autosomal recessive SMPD1 lysosomal storage disorder combining hepatosplenomegaly, lung disease, dyslipidemia, and neurologic involvement; olipudase alfa treats non-CNS manifestations.
Chronic visceral acid sphingomyelinase deficiency
Chronic visceral acid sphingomyelinase deficiency, formerly Niemann-Pick disease type B (OMIM 607616), is an autosomal recessive SMPD1 lysosomal storage disease with hepatosplenomegaly, interstitial lung disease, dyslipidemia, no neurodegeneration, treated with olipudase alfa ERT.
Clinical variant galactosemia
Clinical variant galactosemia, also called variant galactosemia, is a GALT deficiency phenotype with 1-10% residual enzyme activity, often from the S135L variant, neonatal onset, autosomal recessive inheritance, and a better treated outlook than classic galactosemia.
Combined malonic and methylmalonic acidemia
Combined malonic and methylmalonic acidemia (CMAMMA, combined malonic and methylmalonic aciduria) is a rare ACSF3-related inborn error of metabolism with elevated malonic and methylmalonic acid (MMA>MA), normal C3 acylcarnitine, and variable neurologic symptoms.
Combined oxidative phosphorylation defect type 13
Combined oxidative phosphorylation defect type 13 (COXPD13, OMIM 614932) is a rare autosomal recessive mitochondrial disease caused by PNPT1 mutations, causing infant-onset encephalomyopathy, dystonia, and combined respiratory chain deficiency.
Combined oxidative phosphorylation defect type 14
Combined oxidative phosphorylation defect type 14 (COXPD14, OMIM 614946) is a rare autosomal recessive mitochondrial disease from FARS2 mutations on 6p25.1, causing infantile refractory seizures, lactic acidosis, or spastic paraplegia.
Combined oxidative phosphorylation defect type 24
COXPD24 (OMIM 616239) is a rare autosomal recessive mitochondrial disorder caused by NARS2 variants, causing infancy-onset seizures, hypotonia, hearing loss, Leigh or Alpers-like disease, myopathy, and neonatal diabetes.
Combined oxidative phosphorylation defect type 4
Combined oxidative phosphorylation defect type 4 (COXPD4, mitochondrial elongation factor Tu deficiency) is an ultra-rare autosomal recessive TUFM-related mitochondrial translation disorder with neonatal lactic acidosis, encephalopathy, and combined complex I, III, and IV deficiency.
Combined oxidative phosphorylation defect type 8
Combined oxidative phosphorylation defect type 8 (COXPD8, OMIM 614096) is a rare autosomal recessive mitochondrial disease caused by AARS2 mutations, causing complexes I, III, and IV deficiency and fatal infantile hypertrophic cardiomyopathy.
Congenital bile acid synthesis defect type 2
Congenital bile acid synthesis defect type 2 (CBAS2, BASD2, Δ4-3-oxosteroid 5β-reductase deficiency) is a rare autosomal recessive AKR1D1 defect causing neonatal cholestasis, treated with oral cholic acid.
Congenital bile acid synthesis defect type 4
Congenital bile acid synthesis defect type 4, also called AMACR deficiency (OMIM 214950, 614307), is an autosomal recessive peroxisomal disorder from AMACR gene variants, causing infantile cholestasis or adult retinitis pigmentosa, neuropathy, ataxia, and cognitive decline.
Congenital lactase deficiency
Congenital lactase deficiency (alactasia, OMIM 223000) is a rare autosomal recessive LCT-gene disorder, mainly Finnish, causing severe watery diarrhea from breast milk within days of birth; treated with lifelong lactose-free formula.
Congenital lactic acidosis, Saguenay-Lac-Saint-Jean type
Congenital lactic acidosis, Saguenay-Lac-Saint-Jean type, also known as Leigh syndrome, French-Canadian type, is a rare autosomal recessive mitochondrial disease caused by LRPPRC mutations, affecting about 1 in 2,000 births in the Saguenay–Lac-Saint-Jean region of Quebec.
D-2-hydroxyglutaric aciduria
D-2-hydroxyglutaric aciduria (D-2-HGA) is a rare neurometabolic disorder with D-2-HG buildup in body fluids. Type I: recessive D2HGDH mutations; type II: dominant de novo IDH2 gain-of-function mutations, with cardiomyopathy.
D-glyceric aciduria
D-glyceric aciduria (D-glycerate kinase deficiency, D-glyceric acidemia, OMIM 220120) is a rare autosomal recessive GLYCTK-related inborn error of serine and fructose metabolism with highly variable neurological phenotype, first described in 1974.
Desmosterolosis
Desmosterolosis (OMIM 602398), an ultra-rare autosomal recessive cholesterol biosynthesis disorder caused by DHCR24 mutations, with desmosterol accumulation, congenital anomalies, spasticity, and intellectual disability; about 9 reported cases.
Dicarboxylic aminoaciduria
Dicarboxylic aminoaciduria (glutamate-aspartate transport defect, OMIM 222730) is a rare autosomal recessive SLC1A1/EAAT3 disorder causing urinary loss of glutamate and aspartate, sometimes with hypoglycemia, kidney stones, or neuropsychiatric signs.
Dihydropyrimidinuria
Dihydropyrimidinuria, also called dihydropyrimidinase deficiency (DPYS deficiency, OMIM 222748), is a rare autosomal recessive pyrimidine metabolism disorder causing dihydrouracil and dihydrothymine accumulation, variable neurologic and gastrointestinal features, and fluoropyrimidine toxicity risk.
Dimethylglycine dehydrogenase deficiency
Dimethylglycine dehydrogenase deficiency (DMGDH deficiency) is an extremely rare autosomal recessive glycine metabolism disorder, known from a single case with fish-like odor, muscle fatigue, elevated creatine kinase, and 100-fold raised serum dimethylglycine due to the homozygous H109R DMGDH variant.
Disorders of cholesterol synthesis
Disorders of cholesterol synthesis (inborn errors of sterol biosynthesis, ICD-11 5C52.10): eight genetic enzyme blocks from lanosterol to cholesterol, including Smith-Lemli-Opitz syndrome (DHCR7, 1 in 50,000), causing malformations via impaired hedgehog signaling and toxic sterol buildup.
Disorders of creatine metabolism
Disorders of creatine metabolism, also called cerebral creatine deficiency syndromes, are inherited defects in creatine synthesis or transport causing developmental delay, seizures, and intellectual disability.
Disorders of iron metabolism
Disorders of iron metabolism (ICD-11 5C64.1) cover iron deficiency and iron overload conditions such as hemochromatosis, anemia of inflammation, IRIDA, and aceruloplasminemia, all tied to the hepcidin-ferroportin axis.
Disorders of nucleotide metabolism
Disorders of nucleotide metabolism, also called inborn errors of purine and pyrimidine metabolism, are heritable enzyme defects of nucleotide synthesis, salvage, or catabolism; over 30 known, including Lesch-Nyhan disease, ADA deficiency, and orotic aciduria.
Disorders of pyruvate metabolism
Disorders of pyruvate metabolism, chiefly pyruvate dehydrogenase complex deficiency (PDHA1, X-linked) and pyruvate carboxylase deficiency (autosomal recessive), inborn errors causing lactic acidosis and neurological dysfunction, managed with ketogenic diet and supportive care.
Disorders of urea cycle metabolism
Urea cycle disorders (UCDs), also called disorders of urea cycle metabolism, are inherited defects in eight urea cycle enzymes or transporters causing hyperammonemia; about half present neonatally, OTC deficiency is the most common form.