Autosomal Recessive
Also written as AR.
Hereditary haemochromatosis is autosomal recessive (HFE C282Y).
What our notes say
- Hereditary haemochromatosis is autosomal recessive (HFE C282Y). (Internal Medicine End of Semester CAT (MBChB 4): haematology and renal, 30 MCQs )
- Option D is true only for a carrier mother, and sickle cell is autosomal recessive. (Paediatrics end of fourth year special supplementary exam: August 2019, Paper On)
- Inheritance is autosomal recessive, hydroxyurea does not cure, and the diagnosis is by electrophoresis. (Paediatrics end of fourth year main exam: 1 July 2019, Paper One, 99 of 100 MCQs)
- Family history: Consanguinity, affected siblings, parents from malaria‑endemic regions, known carrier status? — Autosomal recessive inheritance; carrier frequency is high in certain Kenyan ethnic groups. (Thalassaemia)
- reinforcing cycle can result, with inflammation producing dyskinesia is inherited in an autosomal recessive fashion.\n\n CHAPTER 16 (Harrisons Pulmonary and Critical Care Medicine)
- Congenital PAP is transmitted in an\nphoma, bronchiolitis, and bronchiolitis obliterans are autosomal recessive manner and is caused by homozygos associated with this condition. (Harrisons Pulmonary and Critical Care Medicine)
Study material on Autosomal Recessive
- Devendra K. Gupta, Krishna M. Goel - Hutchison’s Paediatrics. chdhe-Jaypee Brothers (2012)
- BABY NELSON PEADS
- Harrisons Cardiovascular Medicine 2nd Edition 2
- Kaplan Pediatrics pdf-notes 201506051322 - flattened (2)
- Davidson's Essentials of Medicine - 2nd
- Genetic Disorders: 30 Short Answer Questions — Notes
- Harrisons Pulmonary and Critical Care Medicine
- 7. Approach to a child with diarrhea & constipation
- Addison Disease
- Genetics & Disease: Muscular Dystrophy, CF, Marfan, Diabetes, Cancer — Notes
- Pathology by Dr. Irungu — MCQ Bank
- Genetic Disorders MCQs Examination
Practice questions on Autosomal Recessive
The following Mendelian disorders are autosomal recessive except one. Which one?
- Phenylketonuria
- Hereditary spherocytosis
- Glycogen storage diseases
- Mucopolysaccharidoses
- Galactosemia
Answer: B. Hereditary spherocytosis is autosomal dominant (~75% of cases). The others are autosomal recessive.
: A couple has a child with an autosomal recessive disorder. Neither parent is affected. What is the probability that their next child will be affected?
- 50%
- 100%
- Primarily an incidental laboratory finding
- 75%
- 25%
Answer: A. In autosomal recessive inheritance, two carrier parents have a 25% chance with each pregnancy of having an affected child (homozygous recessive), 50% chance of a carrier, and 25% chance of being unaffected and not a carrier.
Which statement about autosomal recessive disorders is INCORRECT?
- 25% recurrence risk for each birth
- They include almost all inborn errors of metabolism
- Occurs only after chronic exposure
- Onset is frequently early in life
- Parents are usually affected
Answer: B. In autosomal recessive disorders, parents are typically NOT affected but are carriers. The trait manifests in children who inherit two mutant alleles.
A 4-year-old girl presents with recurrent lung infections and pancreatic insufficiency. Sweat chloride test is positive. This autosomal recessive disorder is caused by mutations in which gene? Classic cystic fibrosis presentation. ---
- FBN1 (fibrillin-1)
- CFTR (chloride channel regulator)
- HBB (β-globin)
- RB1 (retinoblastoma)
- LDLR (low-density lipoprotein receptor)
Answer: B.
A child born to phenotypically normal parents develops cystic fibrosis. The inheritance pattern is most consistent with: Two unaffected carrier parents having an affected child is the hallmark of autosomal recessive inheritance. ---
- Autosomal dominant
- X-linked recessive
- Autosomal recessive
- X-linked dominant
- Mitochondrial
Answer: C.
Which of the following features distinguishes autosomal dominant from autosomal recessive inheritance? This vertical pattern is classic for AD; AR instead shows generation skipping (e is a description of AR, not a distinguishing feature stated as such). ---
- Vertical transmission with affected parent in each generation
- Equal gender involvement
- Homozygosity in severe disease
- Skipping of generations
- Requirement of both parents to carry mutant allele
Answer: A.