To the Editor: Severe combined immunodeficiency caused by adenosine deaminase deficiency (ADA-SCID) commonly presents with a phenotype consisting of life-threatening infections, chronic persistent diarrhea, and failure to thrive in the first months of life. 1 In patients with ADA-SCID, toxic metabolites will destroy the lymphocytesandleadtoabsentordecreasednumbersofB,T,andnatural killer cells. Patients with ADA-SCID not only have an immunodeficiency but also other organs might be affected if increased concentrations of the metabolite persist. 2 ADA-SCID is autosomal recessively inherited through mutations in the ADA gene, which is located on chromosome 20q13.12. We present a patient with a severe phenotype of ADA-SCID. She was the second child of healthy unrelated Dutch parents and prematurely born (35 12 weeks gestation) by means of emergency cesarean section because of lack offetal movement and abnormal heart rate. Apgar scores were 6/9/9. Immediately after birth, dysmorphic facial features (including a broad nasal tip, epicanthal folds, large low-set ears, and microretrognathia), microcephaly, erythroderma, andthermolabilitywere noted.Askin biopsy specimen did not show any indicative abnormalities. During the neonatal period, she had a urinary tract infection with Klebsiella species, paronychia of the fingers on both hands, and multiple episodes of cellulitis associated with intravenous catheters for which she received intravenous antibiotic treatments and surgical incisions. She had hypotonia, absent reflexes, blindness and deafness, and an abnormal breathing pattern. Becauseoftheerythrodermaandinfectiousproblemscombined