Babies born in Ireland with several rare diseases are losing out on early diagnosis because only eight conditions are tested for in the "heel-prick test".
Rare Diseases Ireland said the health service is lagging behind other European countries where the average number of diseases screened for at birth is 20, while in the United States it is as many as 50.
"Early diagnosis and treatment can result in dramatic health gain for an increasing number of people with rare diseases. A lack of diagnosis at birth and delayed treatment can have significant adverse consequences," said Philip Watt, chair of the Rare Disease Taskforce.
He was speaking at the launch of 'An Easy Guide to Rare Diseases in Ireland', attended by Health Minister Simon Harris, patient organisations and families.
The taskforce also pleaded for faster access to genetic testing for children and adults who need to know if they have inherited a disease.
Vicky McGrath, CEO of Rare Diseases Ireland, said that the Clinical Medical Genetics waiting list in Crumlin Hospital was 3,021 in December last, an increase of 14.5pc in a year.
"Over one-third of these patients have been on the waiting list for more than a year.
"A failure to provide adequate genetic services means a delay in diagnosis, a lack of appropriate treatment and probable disease progression," she said.
"We need to tackle growing genetics waiting lists over the next two years, and increase the number of consultant geneticists from four to 15.
"Likewise, genetic counselling services are enormously under-resourced and must be addressed in the short-term; it is inhumane to provide a genetic diagnosis over the phone or via post with no follow-up counselling services, as is happening today."
Aine Lawlor (35), from Dublin, who suffers from 22Q Deletion Syndrome, spoke of the need to raise awareness about rare diseases. She was diagnosed at 15 years of age with the condition which leads to fatigue and arthritis-like symptoms.
She told the gathering that "patients and their families are the real experts".
Her words were echoed by Bernadette Gilroy, from Tralee, Co Kerry, whose daughter Maria has PKU, a metabolic genetic disorder which requires a restricted diet in order to avoid brain damage. PKU sufferers want more access to the life-changing drug Kuvan.
It reduces the levels of phenylalanine and allows for sufferers of the condition to eat a more varied diet.
Newborns in Ireland are screened for the condition via the heel-prick test and we have one of the highest rates of PKU in Europe.
About one in every 4,500 babies here is diagnosed with PKU or a milder form of the condition. An average adult diet includes about 70-80g of protein per day but someone with PKU can be confined to as little as 4g.