What is autosomal recessive

Autosomal recessive means two copies of the abnormal gene, one from each parent (one abnormal gene from mum and one abnormal gene from dad), is needed to cause the disorder or disease. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. Autosomal recessive disorders are typically not seen in every generation of an affected family. Cystic fibrosis and sickle cell anemia are common examples of an autosomal recessive genetic disorders.

Autosomal refers to the fact that whatever gene is involved is found on one of the first 22 chromosomes (called the autosomes) and not on the X or Y chromosome (the sex chromosomes).

Recessive refers to the explanation above that you need two copies of the abnormal gene, one from mom and one from dad, in order to have a autosomal recessive condition. The copy you inherit from mom is not working AND the copy you inherit from dad is not working, resulting in zero functioning copies of that gene. With autosomal recessive conditions, if you only have one copy of the non-working gene (called a carrier), you do not have the condition and typically do not have any related symptoms.

What does autosomal recessive mean?

This means that a person must inherit two changed copies of the same gene (one abnormal gene from each parent) in order to have the condition. If a person inherits one abnormal gene and one normal gene, then in most cases that person will be a healthy carrier because the normal gene compensates for the abnormal gene. Being a carrier means that you do not have the condition, but carry a changed copy of the gene on one of a pair of genes.

It is rare to see any history of autosomal recessive conditions within a family because if someone is a carrier for one of these conditions, they would have to have a child with someone who is also a carrier for the same condition. Autosomal recessive conditions are individually pretty rare, so the chance that you and your partner are carriers for the same recessive genetic condition are likely low. Even if both partners are a carrier for the same condition, there is only a 25% chance that they will both pass down the non-working copy of the gene to the baby, thus causing a genetic condition. This chance is the same with each pregnancy, no matter how many children they have with or without the condition.

• If both partners are carriers of the same abnormal gene, they may pass on either their normal gene or their abnormal gene to their child. This occurs randomly.
• Each child of parents who both carry the same abnormal gene therefore has a 25% (1 in 4) chance of inheriting a abnormal gene from both parents and being affected by the condition.
• This also means that there is a 75% ( 3 in 4) chance that a child will not be affected by the condition. This chance remains the same in every pregnancy and is the same for boys or girls.
• There is also a 50% (2 in 4) chance that the child will inherit just one copy of the abnormal gene from a parent. If this happens, then they will be healthy carriers like their parents.
• Lastly, there is a 25% (1 in 4) chance that the child will inherit both normal copies of the gene. In this case the child will not have the condition, and will not be a carrier.

These possible outcomes occur randomly. The chance remains the same in every pregnancy and is the same for boys and girls.

Figure 1 illustrates autosomal recessive inheritance. The example below shows what happens when both dad and mum is a carrier of the abnormal gene, there is only a 25% chance that they will both pass down the abnormal gene to the baby, thus causing a genetic condition.

Key points to remember

• A person must inherit two copies of a abnormal gene, one from each parent, in order to be affected by the condition (25% chance). If a person inherits only one abnormal gene then they will be a carrier (50% chance). These outcomes occur randomly. They remain the same in every pregnancy and are the same for boys and girls.
• A abnormal gene cannot be corrected – it is present for life.
• A abnormal gene is not something that can be caught from other people. They can still be a blood donor, for example.
• People often feel guilty about a genetic condition which runs in the family. It is important to remember that it is no-one’s fault and no-one has done anything to cause it to happen.

Figure 1. Autosomal recessive inheritance

Autosomal recessive disorders

Autosomal recessive disorders list

• 5 alpha reductase deficiency (5 alpha-reductase type 2 deficiency)
• 21-hydroxylase deficiency
• ABCD Syndrome (albinism, black lock of hair, cell migration disorder of the neurocytes of the gut, and sensorineural deafness syndrome)
• Abetalipoproteinemia (Bassen-Kornzweig syndrome or Bassen-Kornzweig disease)
• Achalasia Microcephaly Syndrome
• Achondrogenesis type 1A and type 1B
• Acral peeling skin syndrome
• Acrodermatitis enteropathica
• Achromatopsia
• Acrorenal Syndrome, Autosomal Recessive
• Aicardi-Goutieres Syndrome
• Alacrima, Achalasia, And Mental Retardation Syndrome
• Alstrom Syndrome
• Anonychia congenita (congenital absence of nails, isolated congenital anonychia or autosomal recessive nonsyndromic congenital nail disorder type 4)
• Arginase deficiency (hyperargininemia, argininemia, arginase deficiency disease or ARG1 deficiency)
• Argininosuccinate lyase deficiency (argininosuccinic aciduria or argininosuccinic acid lyase deficiency)
• Arrhythmogenic cardiomyopathy
• Athabaskan Brainstem Dysgenesis Syndrome
• Bardet–Biedl syndrome
• Bare lymphocyte syndrome (Bare lymphocyte syndrome type 1 and Bare lymphocyte syndrome type 2)
• Beaulieu‐Boycott‐Innes syndrome
• Bernard-Soulier syndrome
• Beta-Ketothiolase Deficiency
• Beta thalassemia
• Bifid Nose, Autosomal Recessive
• Biotinidase deficiency
• Bjornstad Syndrome
• Bloom syndrome
• Bowen‐Conradi syndrome
• Branched-Chain Keto Acid Dehydrogenase Kinase Deficiency
• Brittle Cornea Syndrome
• Brody myopathy (Brody disease)
• Camptodactyly With Fibrous Tissue Hyperplasia And Skeletal Dysplasia
• Camptodactyly-Arthropathy-Coxa Vara-Pericarditis Syndrome
• Cardiomyopathy-Hypotonia-Lactic Acidosis Syndrome
• Carnitine palmitoyltransferase 1 deficiency
• Carpenter syndrome (acrocephalopolysyndactyly 2, acrocephalopolysyndactyly type II)
• Cartilage hair hypoplasia (McKusick’s metaphyseal chondrodysplasia syndrome)
• Cerebellar atrophy, short stature
• Cerebrotendinous xanthomatosis (cerebral cholesterinosis, cerebrotendinous cholesterinosis or Van Bogaert-Scherer-Epstein disease)
• Chediak Higashi syndrome
• Citrullinemia (citrullinemia type 1 and citrullinemia type 2)
• Cockayne Syndrome
• Cohen syndrome (Pepper syndrome, Norio syndrome, prominent incisors-obesity-hypotonia syndrome or obesity-hypotonia syndrome)
• Combined pituitary hormone deficiency
• Congenital adrenal hyperplasia
• Congenital factor VII deficiency (congenital factor 7 deficiency or congenital prothrombin deficiency)
• Congenital factor XIII deficiency (congenital factor 13 deficiency)
• Congenital hepatic fibrosis (congenital fibrose liver)
• Congenital hyperinsulinism
• Congenital insensitivity to pain (CIP)
• Congenital insensitivity to pain with anhidrosis (CIPA)
• Congenital Stationary Night Blindness 1G
• Congenital Vertebral-Cardiac-Renal Anomalies Syndrome
• CoQ-Responsive OXPHOS Deficiency
• Cranioectodermal dysplasia‐like
• Craniometaphyseal Dysplasia, Autosomal Recessive
• Craniosynostosis Syndrome, Autosomal Recessive
• Crigler-Najjar syndrome
• Cutis Laxa With Severe Pulmonary, Gastrointestinal And Urinary Anomalies
• Cystic fibrosis
• Cystinosis
• Cystinuria
• Diastrophic dysplasia or diastrophic dwarfism
• Dilated cardiomyopathy with ataxia syndrome
• Donnai-Barrow Syndrome
• Donohue Syndrome
• Dubin Johnson syndrome
• Dyskeratosis Congenita, Autosomal Recessive 2
• Dyskeratosis Congenita, Autosomal Recessive 3
• Dyskeratosis Congenita, Autosomal Recessive 5
• Ehlers-Danlos Syndrome, Kyphoscoliotic Type
• Ellis-van Creveld syndrome
• Eosinophil Peroxidase Deficiency
• Epidermolysis verruciformis
• Erythropoietic protoporphyria
• Fanconi anemia
• Farber disease (Farber’s disease, Farber’s lipogranulomatosis, Farber-Uzman syndrome, acid ceramidase deficiency, acylsphingosine deacylase deficiency or ceramidase deficiency)
• Fibular Hypoplasia And Complex Brachydactyly
• Fraser Syndrome
• Fumarase deficiency or Fumaric aciduria
• Galloway-Mowat Syndrome
• Gitelman syndrome (familial hypokalemia-hypomagnesemia)
• Glanzmann thrombasthenia
• Glycosylphosphatidylinositol Biosynthesis Defect 15
• GM1 gangliosidosis
• Griscelli syndrome
• Hair Defect With Photosensitivity And Intellectual Disability Syndrome
• Hartnup disease
• Heart Defects-Limb Shortening Syndrome
• Hereditary fructose intolerance
• Hermansky-Pudlak syndrome
• Homocystinuria Without Methylmalonic Aciduria
• Hurler syndrome
• Hutchinson-Gilford Progeria Syndrome
• Hydrocephalus, Nonsyndromic, Autosomal Recessive 1
• Hydrolethalus Syndrome
• Hyper-IgM Syndrome Type 2
• Hyperlipoproteinemia, Type 1D
• Hypermanganesemia With Dystonia 2
• Hyperphenylalaninemia Due To Tetrahydrobiopterin Deficiency
• Hypertelorism, Microtia, Facial Clefting Syndrome
• Hypoparathyroidism-Retardation-Dysmorphism Syndrome
• Hypophosphatasia
• Hypoprothrombinemia (inherited prothrombin deficiency, factor II deficiency or dysprothrombinemia)
• Immunodeficiency 27A
• Immunodeficiency-Centromeric Instability-Facial Anomalies Syndrome
• Inherited Pseudoxanthoma Elasticum
• JMP Syndrome (joint contractures, muscle atrophy, microcytic anemia and panniculitis-induced lipodystrophy syndrome)
• Johanson-Blizzard Syndrome
• Joint Laxity, Short Stature, And Myopia
• Joubert syndrome related disorder
• Kahrizi Syndrome
• Kartagener syndrome
• Lamellar ichthyosis
• Lafora disease or Lafora progressive myoclonus epilepsy
• Laron Syndrome
• Laurence-Moon Syndrome
• Leigh disease
• Leukocyte adhesion deficiency
• Limb girdle muscular dystrophy 2H
• Limb girdle muscular dystrophy 2I
• Limb girdle muscular dystrophy 2S
• Lipase Deficiency, Combined
• MCAD deficiency (medium-chain acyl-coenzyme A dehydrogenase deficiency)
• McArdle disease (glycogen storage disease type 5)
• Meckel Gruber syndrome
• Mendelian Susceptibility To Mycobacterial Diseases Due To Complete IL12B Deficiency
• Mendelian Susceptibility To Mycobacterial Diseases Due To Complete IL12RB1 Deficiency
• Mendelian Susceptibility To Mycobacterial Diseases Due To Complete ISG15 Deficiency
• Meier-Gorlin Syndrome
• Methylmalonic aciduria or methylmalonic acidemia
• Microcephaly And Chorioretinopathy 2
• Microcephaly, Growth Restriction, And Increased Sister Chromatid Exchange 2
• Microphthalmia With Limb Anomalies
• Morquio syndrome (mucopolysaccharidosis type IV)
• Mulibrey Nanism
• Multinucleated Neurons-Anhydramnios-Renal Dysplasia-Cerebellar Hypoplasia-Hydranencephaly Syndrome
• Multiple Intestinal Atresia
• MUTYH-Related Attenuated Familial Adenomatous Polyposis
• Myotonia Congenita, Autosomal Recessive
• Nasu-Hakola Disease
• Nephronophthisis‐juvenile
• Nestor-Guillermo Progeria Syndrome
• Netherton syndrome
• Niemann-Pick Disease
• Nijmegen Breakage Syndrome
• Nonsyndromic mental retardation
• Oculocutaneous albinism type 1A
• Oculodentodigital Dysplasia, Autosomal Recessive
• Omenn syndrome (familial reticuloendotheliosis)
• Ochoa Syndrome
• Osteoporosis-Pseudoglioma Syndrome
• Palmoplantar keratodermas
• Peeling skin syndrome
• Pendred Syndrome
• Peroxisome Biogenesis Disorder
• Perrault Syndrome
• Persistent Hyperplastic Primary Vitreous, Autosomal Recessive
• PHARC Syndrome (Polyneuropathy, Hearing loss, Ataxia, Retinitis pigmentosa and Cataracts syndrome)
• Phenylketonuria
• Pierson Syndrome
• Primary Ciliary Dyskinesia
• Primary hyperoxaluria type 1, 2 and 3
• Propionic acidemia
• Pyruvate kinase deficiency
• Pseudo-TORCH Syndrome
• Pseudoxanthoma elasticum
• Rapadilino Syndrome
• Refsum disease
• Restrictive dermopathy
• Rhizomelic chondrodysplasia punctata
• Roberts Syndrome
• Sandhoff disease (Sandhoff-Jatzkewitz-Pilz disease, GM2 gangliosidosis type 2 or total hexosaminidase deficiency)
• Sanfilippo syndrome (mucopolysaccharidosis type III)
• Salt And Pepper Syndrome
• Schwartz-Jampel Syndrome
• Seckel Syndrome (bird-headed dwarfism, microcephalic primordial dwarfism or Seckel type dwarfism)
• Segawa syndrome
• Senior-Loken Syndrome
• Sensorineural deafness
• Shwachman Diamond syndrome
• Sickle cell anemia
• Sitosterolemia
• Sly syndrome (mucopolysaccharidosis type VII)
• Smith-Lemli-Opitz syndrome
• Sotos Syndrome
• Spinal muscular atrophy
• Spondyloepiphyseal Dysplasia Tarda, Autosomal Recessive
• Succinylcholine sensitivity
• Susceptibility To Infection Due To TYK2 Deficiency
• Tangier disease (A-alphalipoprotein Neuropathy, Familial High Density Lipoprotein Deficiency Disease, Familial Hypoalphalipoproteinemia)
• TAR syndrome (thrombocytopenia-absent radius syndrome)
• Temtamy Preaxial Brachydactyly Syndrome
• Tetra amelia syndrome
• TH-Deficient Dopa-Responsive Dystonia
• Thiamine-Responsive Megaloblastic Anemia Syndrome
• Thyroid dyshormonogenesis 1
• Triple A syndrome (AAA syndrome, Achalasia-Addisonianism-Alacrima syndrome or Allgrove syndrome)
• Turcot syndrome
• Tyrosinemia
• Usher syndrome Type 1B
• Usher syndrome Type 1F
• UV-Sensitive Syndrome
• Vici Syndrome
• von Gierke disease (glycogen storage disease type )
• VLDLR with cerebellar hypoplasia
• Walker Warburg syndrome
• Warburg Micro Syndrome
• Werner syndrome
• Wilson disease (hepatolenticular degeneration)
• Wolcott-Rallison Syndrome
• Wolfram syndrome
• Wolman disease
• Xeroderma pigmentosum
• Zellweger spectrum disorder
• Zlotogora-Ogur Syndrome
• Autosomal Recessive Alport Syndrome
• Autosomal Recessive Ehlers-Danlos Syndrome, Vascular Type
• Autosomal Recessive Emery-Dreifuss Muscular Dystrophy
• Autosomal Recessive Kenny-Caffey Syndrome
• Autosomal Recessive Robinow Syndrome
• Autosomal Recessive Stickler Syndrome
• Autosomal Recessive Amelia
• Autosomal Recessive Axonal Hereditary Motor And Sensory Neuropathy
• Autosomal Recessive Brachyolmia
• Autosomal Recessive Centronuclear Myopathy
• Autosomal Recessive Cerebellar Ataxia
• Autosomal Recessive Cerebral Atrophy
• Autosomal Recessive Complex Spastic Paraplegia
• Autosomal Recessive Congenital Ichthyosis
• Autosomal Recessive Cutis Laxa Type 1
• Autosomal Recessive Cutis Laxa Type 2
• Autosomal Recessive Disease Associated With Punctate Palmoplantar Keratoderma As A Major Feature
• Autosomal Recessive Disease With Diffuse Palmoplantar Keratoderma As A Major Feature
• Autosomal Recessive Disease With Focal Palmoplantar Keratoderma As A Major Feature
• Autosomal Recessive Distal Hereditary Motor Neuropathy
• Autosomal Recessive Distal Myopathy
• Autosomal Recessive Distal Renal Tubular Acidosis
• Autosomal Recessive Faciodigitogenital Syndrome
• Autosomal Recessive Familial Mediterranean Fever
• Autosomal Recessive Hereditary Sensory And Autonomic Neuropathy
• Autosomal Recessive Humeroradial Synostosis
• Autosomal Recessive Hydrocephalus Due To Congenital Stenosis Of Aqueduct Of Sylvius
• Autosomal Recessive Hypohidrotic Ectodermal Dysplasia
• Autosomal Recessive Hypophosphatemic Rickets
• Autosomal Recessive Infantile Hypercalcemia
• Autosomal Recessive Intermediate Charcot-Marie-Tooth Disease
• Autosomal Recessive Isolated Diffuse Palmoplantar Keratoderma
• Autosomal Recessive Limb-Girdle Muscular Dystrophy
• Autosomal Recessive Mendelian Susceptibility To Mycobacterial Diseases Due To Complete IFNgammaR2 Deficiency
• Autosomal Recessive Mendelian Susceptibility To Mycobacterial Diseases Due To Complete RORgamma Receptor Deficiency
• Autosomal Recessive Mendelian Susceptibility To Mycobacterial Diseases Due To Partial IFNgammaR2 Deficiency
• Autosomal Recessive Multiple Pterygium Syndrome
• Autosomal Recessive Nager syndrome
• Autosomal Recessive Non-Syndromic Intellectual Disability
• Autosomal Recessive Nonsyndromic Deafness
• Autosomal Recessive Ocular Albinism
• Autosomal Recessive Omodysplasia
• Autosomal Recessive Optic Atrophy
• Autosomal Recessive Osteopetrosis
• Autosomal Recessive Polycystic Kidney Disease
• Autosomal Recessive Progressive External Ophthalmoplegia
• Autosomal Recessive Proximal Renal Tubular Acidosis
• Autosomal Recessive Pure Spastic Paraplegia
• Autosomal Recessive Severe Congenital Neutropenia
• Autosomal Recessive Sideroblastic Anemia
• Autosomal Recessive Spondylocostal Dysostosis