Related Experiment Video
Updated: Feb 4, 2026

Isolation and Cryopreservation of Neonatal Rat Cardiomyocytes
Published on: April 9, 2015
Isolated GGT elevation in prolonged neonatal jaundice: detection of heterozygous alpha-1 antitrypsin deficiency
Patrick Orji1, Nabiha Asad2, Heba Mansour2
1Paediatrics, Manchester University NHS Foundation Trust, Manchester, UK patrick.orji@nhs.net.
Abstract:
Prolonged neonatal jaundice is usually benign but can occasionally indicate serious hepatobiliary disease. Current UK guidelines emphasise bilirubin-based screening, which may overlook atypical biochemical profiles. A term neonate presented with persistent jaundice but was otherwise well, with normal stools and urine. Bilirubin levels were normal, yet gamma-glutamyl transferase (GGT) was markedly elevated at 1101 U/L. Further testing revealed reduced alpha-1 antitrypsin (A1AT) levels and PiMZ heterozygosity. Imaging showed no structural abnormality. Over follow-up, transaminases-alanine aminotransferase and aspartate aminotransferase-rose, suggesting evolving hepatic involvement. Isolated GGT elevation, though uncommon, may represent the earliest clue to hepatobiliary disease. Heterozygous A1AT deficiency is not always benign and warrants ongoing biochemical surveillance. Clinicians should interpret guideline frameworks carefully to ensure atypical but clinically significant disease presentations are not overlooked.
Related Concept Videos
Freezing Point Depression and Boiling Point Elevation
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
Elevation of Intermediate Points on Vertical Curves
SN1 Reaction: Stereochemistry
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
SN1 Reaction: Kinetics
However, Sir Christopher Ingold and Edward D. Hughes, who studied the kinetics of various nucleophilic substitution reactions, noticed that a tertiary alkyl halide does undergo a nucleophilic substitution reaction in the presence of a weak nucleophile. While studying the substitution...
SN1 Reaction: Mechanism
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...
Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.

