Newfound features associated with Hennekam Syndrome (Intestinal Lymphangiectasia–Lymphedema–Intellectual–Disability Syndrome) complicated with comorbid Waldmann's Disease resulting in Celiac Disease

KEY CLINICAL MESSAGE: Adequate evaluation of patients with Hennekam Syndrome (HS) is challenging for physicians, because of multi‐organ involvement and complex pathophysiology. We report the first case in an African American with lymphedema, who developed protein‐losing enteropathy (PLE) and was successfully diagnosed with HS from cause‐and‐effect complications by Waldmann's Disease (WD) and comorbid Celiac Disease (CD). ABSTRACT: As far as we know, this is the 51st case of HS worldwide and the first one in an African American. The examined patient met all diagnostic criteria for HS, suggesting a dysfunction in the development of the lymphatic system, with associated comorbidities including developmental delay, gastrointestinal pathologies, facial and hearing abnormalities, and cardiac defects. Primary intestinal lymphangiectasia (WD) is a consequence of HS, which ultimately results in PLE and worsening interstitial lymph buildup. Based on our findings, 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‐thyroid stimulating hormone 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 inflammation and subsequent 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, and leading to gastropathy. Considering the examined patient's history of gastroenteritis and the literature stating that CD is a non‐mucosal cause of gastropathy and PLE, it is suggested that sequelae of GI complications occur in a cause‐and‐effect chain in HS. HS results in WD, which causes CD, resulting in hypertrophic gastropathy and loss of parietal and chief cells, eventually leading to malabsorption and PLE (Figure 1). HS primarily affects various organs due to inflammatory‐mediated damage and accumulation of lymph fluid. Other findings for HS include keratoconjunctivitis sicca (dry eye disease), fibrous lymphedema exhibiting lymphorrhea, chylous ascites, anemia, and parathyroid abnormalities. Immune impairment in HS predisposes patients to autoimmune disorders, therefore autoimmunity (CD) and WD are concomitant comorbidities of HS. HS‐associated comorbidities are primarily due to inflammation and damage to immune cell transport or underlying health conditions affecting proper lymphatic function. However, it is suggested that HS mutations may disrupt the development of the lymphatic system leading to further complication. complications can be compound heterozygous, and there is a need for further research to identify nearby genes that can cause concomitant co‐morbidity.