The older brother, P1 (Figure 1A, B), is the first child of first-cousin parents of Moroccan origin. He was born at term, with normal health indicators and metrics, following an uneventful pregnancy. P1 has an adult height of 162 cm, which is close to 167 cm, his predicted adult height based on the heights of his parents (his father is 168 cm tall and his mother is 155 cm tall). He was diagnosed with insulin-dependent diabetes at the age of 5 years. He was subsequently diagnosed with exocrine pancreas insufficiency at the age of 9 years, following the observation of bulky stools and steatorrhea with levels of fat in stool at 12 g/24 hr. At this stage, a diagnosis of cystic fibrosis was excluded and a computed tomography (CT) scan of the pancreas was normal. At the age of 14 years, nasal obstruction occurred, with infiltrates found in both the nose and the right maxillary sinus (Figure 1C). P1 was then diagnosed with RS. Several operations were required to free the nasal fossae, between the ages of 14 and 18 years. An improvement was observed after the initiation of antibiotic treatment, but multiple relapses occurred 10 months after treatment, despite the use of various combinations of antibiotics. Apparently spontaneous recovery was observed from the age of 18 years onwards. Biological signs of inflammation persisted, with both a high erythrocyte sedimentation rate (>50 mm) and polyclonal hypergammaglobulinemia (IgG = 15.3 g/l, IgA = 4.2 g/l, IgM = 2.8 g/l). Finally, P1 developed a very mild contracture of the fingers and toes at the age of 12 years (Figure 1D). At last follow up, the patient was 33 years old and had insulin-dependent diabetes and exocrine pancreatic deficiency. He is doing well, with daily subcutaneous insulin and oral pancreatic extract treatments, which have normalized his glycemia and steatorrhea. He has required no further surgery since the age of 18 years, but still suffers from chronic nasal obstruction and an enlarged nose due to the presence of a nasal mass (Figure 1B). He recently suffered from local pain of the knee. X-ray revealed lytic bone lesions of both patellas (Figure 1E). No other lesions were detected on X-ray or bone scintigraphy. This patient is otherwise healthy (Table 1). Both cardiac morphology and function were normal on cardiac ultrasonography (US). Dermatologist examination revealed no pigmented hypertrichotic skin lesions and skin biopsies taken at 3 different sites were normal. Speech and tone audiometries were normal. Ophtalmologic examination revealed mild diabetic retinopathy but no uveitis and no histiocytic infiltration.