Carriers of autosomal recessive conditions : are they really 'unaffected?'

© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ..

Mendel's Law of Dominance suggests that recessive disease expression requires the inheritance of two mutated alleles as the dominant, wildtype allele suppresses disease presentation leading to the expression of physiological normal phenotypes. However, there is existing evidence that challenges this school of thought. Here, we summarise existing literature evaluating metabolic and health impacts among carriers of autosomal recessive conditions, focusing on phenylketonuria (PKU), classical homocystinuria, galactosemia and Usher syndrome as examples. Our findings suggest that carriers, often described as 'unaffected', may actually display attenuated symptoms for the recessive disease they are carrying. For instance, PKU is an inborn error of metabolism characterised by the build-up of plasma phenylalanine attributed to the deficiency of the phenylalanine hydroxylase (PAH) enzyme. While less severe, PKU carriers also exhibit this impaired enzymatic activity, leading to elevated plasma phenylalanine levels, especially after phenylalanine consumption. Related to these metabolic alterations in the PAH pathway, there is early evidence to suggest that PKU carriers may have compromised cognitive and mental health outcomes. Overall, research on the health and metabolic impacts of PKU carriers is sparse, with most studies conducted several decades ago. However, early evidence suggests that intermediate phenotypes among carriers of autosomal recessive conditions are plausible. The illustrated possible intermediate phenotypes observed among carriers necessitates future research to determine possible clinical implications among this population.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:61

Enthalten in:

Journal of medical genetics - 61(2023), 1 vom: 21. Dez., Seite 1-7

Sprache:

Englisch

Beteiligte Personen:

Hames, Amber [VerfasserIn]
Khan, Sophia [VerfasserIn]
Gilliland, Clara [VerfasserIn]
Goldman, Lucy [VerfasserIn]
Lo, Hillary Wh [VerfasserIn]
Magda, Kevin [VerfasserIn]
Keathley, Justine [VerfasserIn]

Links:

Volltext

Themen:

47E5O17Y3R
EC 1.14.16.1
Genetic carrier screening
Genetic diseases, inborn
Genetic heterogeneity
Genetics
Inborn genetic diseases
Journal Article
Phenylalanine
Phenylalanine Hydroxylase
Review

Anmerkungen:

Date Completed 25.12.2023

Date Revised 25.12.2023

published: Electronic

Citation Status MEDLINE

doi:

10.1136/jmg-2023-109563

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM362713405