As far as we know, this is the 51st case of Hennekam Syndrome (HS) worldwide and the first one in an African American. Our patient met all diagnostic criteria for HS, type 2 (FAT4 mutation), as the disease onset was in adolescence.Primary intestinal lymphangiectasia (Waldmann's disease, WD) is a consequence of HS, which ultimately results in protein-losing enteropathy (PLE) and worsening interstitial lymph buildup.4,5 Based on our findings, celiac disease (CD), a complication not yet reported in HS, may arise from WD. Other autoimmune diseases may be seen in HS: a previous report demonstrated positive anti-TSH antibodies in HS patients. We propose that in HS, increased interstitial lymph (WD, if intestinal) with protein loss induces TNF-α- and IL-6-mediated immune reactions in the affected visceral organs, causing autoimmune pathologies.The interstitial lymph fluid-induced TNF-α and IL-6-mediated immunopathogenic reactions lead to the destruction of the intestinal mucosa. The chronic inflammatory increase in TGF-β causes gastric mucosa hypertrophy, which results in gastric fold thickening. Eventually, wider tight junctions develop, increasing gastric mucosa permeability, which leads to gastropathy. Considering our patient’s history of gastroenteritis and the literature stating that CD is a non-mucosal cause of gastropathy and PLE, we suggest that sequelae of GI complications in HS occur in a cause-and-effect chain. HS results in WD, which causes CD, which in turn results in hypertrophic gastropathy and loss of parietal and chief cells, which eventually leads to malabsorption and PLE (Fig. 1).Other findings for HS included keratoconjunctivitis sicca (dry eye disease), fibrous lymphedema exhibiting lymphorrhea, chylous ascites, anemia, and PTH abnormalities. Autoimmunity (CD) and WD are concomitant comorbidities of HS.HS mutations can be compound heterozygous, and there is a need to identify more nearby genes that can cause concomitant co-morbidity. FAT1 mutation has been associated with hypertrophy of cardiomyocytes. This is consistent with the present patient’s echocardiogram showing mild concentric left ventricular hypertrophy. The concomitant presence of pathologies that all involve FAT genes suggests gene mutations in proximity.