A new mental retardation – dysmorphic condition?
The patient is a 10-years-old male. He is the second child of a young, healthy and non-consanguineous couple of Portuguese origin; the family history is unremarkable. Pregnancy was complicated by hyperemesis. Delivery was at term, weighting 2.320 kg and measuring 45 cm. He was first seen in our service due to hyperphenylalaninemia. Neonatal screening detected phenylalanine levels of 6.3 mg% (reference value = up to 4.0 mg%). Clinical and laboratory follow-up showed that hyperphenylalaninemia had a peak of 9.0 mg% at age three months, reaching normal value of 2.8 mg% at age 7 months. Development was borderline and he first attended a normal school. Due to learning disability, he was transferred for a special school. Development also included low weight gain, undescedent testes, unilateral myopia (0.75) and pigmented naevi which are increasing with age. Clinical evaluation at the age 8 years revealed a normal stature of 117.5 cm, a low weight of 16.2 Kg with and a low OFC of 58.5 cm. Besides microcephaly, he was noted to present thin habitus, brachycephaly with a flat occiput, broad forehead, maxilary hypoplasia, mild retrognatia, limited opening of the mouth, dysmorphic ears, downslanting palpebral fissures, blue sclerae, rarefaction of eyelids and eyelashes, fovea coccigea, long and thin fingers, hypoplastic toenails and multiple pigmented naevi over the trunk and face. Radiographic evaluation revealed diffuse impressions in the skul, delayed bone age and carpal bone fusion. Complementary tests included a BERA showing normal hearing. Chromosomal analysis in lymphocytes with G-banding showed a normal 46,XY male constitution. No mutation was identified in the genes PAH, FGFR2, FGFR3 and TWIST.