PREPLdeficiency is recessively inherited. We have two copies of the PREPLgene, one from our biological mother and one from our biological father. If one of these two copies contains a mistake, the other copy is sufficient to avoid signs of PREPLdeficiency. However, if both parents carry a copy of PREPLwith a mistake, there is a chance of ¼ that their child will inherit the two copies of PREPLwith a mistake (no copy of PREPLwithout mistake) and will develop the signs of PREPLdeficiency.
The PREPLgene can be seen as a text. Different errors or mutations can occur in this text. In some patients, 1 letter of the text has changed at an important place, and in others whole parts of the text or even the whole text of PREPLhave disappeared (deletions). It also happens that part of the text of genes next to PREPLhas disappeared, causing signs related to these other genes. One gene close to PREPLis related to kidney stones due to cystinuria. When this gene is absent together with PREPL, this causes the hypotonia-cystinuria syndrome.
Diagnosis of PREPLdeficiency can be done by reading the text of the PREPL gene with different techniques.
In several children with PREPLdeficiency, the first diagnosis that was considered was the Prader-Willi syndrome, as this syndrome resembles PREPL deficiency in some ways. However, PREPLdeficiency is considered to be less severe than the Prader-Willi syndrome.
PREPLencodes an enzyme (a protein that facilitates specific biochemical reactions in the body) of which the function is still unclear. However, we know that PREPLhas a role in the communication between nerve cells and between muscle and nerve.
If it is unclear whether a mistake in the text of the PREPL gene is important or not, an experimental functional test can be done in fresh blood to see if PREPL is active or not.
PREPL