POLD3 Deficiency (when both copies of the gene are affected; “biallelic” or recessive form)
Immune system:
The immune system is the system that defends our body against all pathogens and infections. Children with this condition have a very weak immune system. This is a type of severe immune deficiency (called SCID) or a related condition (called Omenn syndrome), that is characterized by repetitive severe infections requiring hospitalizations, that appear at a very early age. Babies may also have red, irritated skin (erythroderma), and high numbers of a certain type of white blood cell (eosinophils).
Development:
Many children show delays in development and in reaching the normal milestones, due to problems affecting the neurological system (brain and nerves).
Hearing:
Some babies are born with hearing loss due to problems in the inner ear (sensorineural hearing loss).
Growth and other organs:
Some children may have slow growth or problems in other organs, but this is still being studied because only a few cases have been reported so far.
Age when symptoms appear:
Usually in early infancy.
Tests and scans:
Blood tests often show very low levels of certain immune cells which are cells present in the blood and important for the normal defense mechanisms (white blood cells, especially T cells). Scans or biopsies may be done depending on what complications the child has (for example, infections or effects after a transplant).
POLD3 – Dominant form (when only one copy of the gene is affected)
Hearing:
Adults usually start to notice hearing loss in both ears around age 40–50. The hearing loss gets worse over time and affects the inner ear.
Balance:
Some people may also have balance problems or dizziness because of inner ear (vestibular) weakness.
Progression:
This type starts in adulthood and slowly worsens over the years, unlike the early, more severe form seen in infants with two faulty copies of the gene.
POLD3