Abstract
The recent report by Vela-Amieva et al. 1 raised the important point that delay in referral of patients with phenylketonuria (PKU) leads to delayed diagnosis and treatment. This will have an impact on children's neurodevelopment. 2 Vela-Amieva et al. concluded that the main reason for late referral of PKU patients was that newborn screening (NBS) for PKU is not mandatory in Mexico. Despite mandatory PKU NBS in China, delay in referral of patients also occurs here. We have analyzed our data from 11 years of NBS and four years of high-risk screening in patients symptomatic for PKU.
From 1999 to 2010, 160 patients were diagnosed with PKU after NBS screening, and 11 after high-risk screening. Of the 160 patients diagnosed through NBS, 90 (56.3%) attended the centre after 30 days of age. Diagnostic delay following attendance was over 30 days in four patients (age at diagnosis: 104 days, 105 days, 100 days and 289 days). The mean age on arrival at the centre for the 11 symptomatic patients was three years and one month (range: 41 days – 11 years). All the 11 patients detected by high-risk screening were due to absence of newborn screening in their birth places.
As the average coverage rate around China is about 40%, 3 the absence of screening is also a reason in some regions with low coverage rate. In our province, no cases have been found to be missed by NBS with a screening coverage rate of 99%. Delay in referral due to the absence of NBS screening is therefore not a problem in our province, however, delay in referral for other reasons is a great concern. Although our staff repeatedly contacted the parents of newborns in our programme, many parents persisted in bringing their children to our centre more than 30 days after birth.
The major reason is that China has a postpartum culture of ‘zuo yue zi’ (sitting out the month). Mother and newborn stay indoors and are secluded for one month after birth. The parents may thus ignore our advice about the potential harm of delayed diagnosis and treatment for the disease. Many parents tell us, ‘My child has no symptoms and he/she looks so well’. Though asymptomatic in the first months of life, the baby may have been exposed to a high level of phenylalanine which will later lead to neurodevelopmental delay.
In our centre, some parents may also not follow our recommendation for treatment of their children after diagnosis. From 1999 to 2008, a total of 24 children received no treatment after diagnosis, due to the parents’ refusal. Four children were discontinued treatment after a period due to the family's economical burden. Refusing or discontinuing treatment occurs rarely since 2008 when our centre received funding for PKU patients from families of low socio-economic level. It appears therefore that the financial burden was the main reason for refusing or discontinuing treatment.
It is now urgent that, in order to solve these problems, the coverage rate of newborn screening around China should be increased; most importantly, the government should consider including PKU into the basic medical insurance in China.