PKU-affected women themselves are not at risk of additional complications during pregnancy.In most countries, women with PKU who wish to have children are advised to lower their blood Phe levels (typically to between 2 and 6 mg/dL) before they become pregnant, and carefully control their levels throughout the pregnancy. This is achieved by performing regular blood tests and adhering very strictly to a diet, in general monitored on a day-to-day basis by a specialist metabolic dietitian. In many cases, as the fetus liver begins to develop and produce PAH normally, the mothers blood Phe levels will drop, requiring an increased intake to remain within the safe range of 2–6 mg/dL. The mothers daily Phe intake may double or even triple by the end of the pregnancy, as a result. When maternal blood Phe levels fall below 2 mg/dL, anecdotal reports indicate that the mothers may experience adverse effects, including headaches, nausea, hair loss, and general malaise. When low phenylalanine levels are maintained for the duration of pregnancy, there are no elevated levels of risk of birth defects compared with a baby born to a non-PKU mother. Epidemiology
The average number of new cases of PKU varies in different human populations. United States Caucasians are affected at a rate of 1 in 10,000. Turkey has the highest documented rate in the world, with 1 in 2,600 births, while countries such as Finland and Japan have extremely low rates with fewer than one case of PKU in 100,000 births.
Affected teeth usually appear as brownish-blue, brown or yellow. Translucent “opalescence” is often one of the characteristics to describe teeth with DD-2. In some cases teeth might show slightly amber coloured but in most of the cases permanent teeth are unaffected and appear normal regardless of colour, shape and size. Dental X-rays are the key to diagnose dentine dysplasia, especially on permanent teeth. Abnormalities of the pulp chamber is the main characteristic to make a definitive diagnosis.In the primary teeth, coronal dentin dysplasia may appear similar to Dentinogenesis Imperfecta type II (DG-II) but if abnormalities features appear to be more pronounced in the permanent teeth, then consider changing the diagnosis to DGI-II instead of DD-2. Radiographic features
In coronal type, teeth show normal roots containing enlarged pulp with abnormal extensions towards the roots, which is often described as “thistle tube” shaped on dental radiographs. As well as this, numerous pulp stones can be often found in the pulp chambers due to abnormal calcifications. In primary teeth, the pulp chamber is usually completely obliterated but in permanent teeth, the pulp may become partially obliterated after eruption. Histological features
There are a few studies and proposals that were designed to explain the pathogenesis of DD but the main reason of the cause still remains unclear in the dental literature. Logan et al., suggested that dental papilla is the cause of abnormal root growth or development. They also proposed that calcification of multiple degenerative foci within the papillae reduce the growth and eventually leads to pulpal obliteration.