Table 2.
Chylomicron Retention Disease Diagnosis
| Clinical | |
| Anthropometry | Constant but unspecific failure to thrive in early infancy (1-6 months) |
| Digestive | Chronic malabsorptive diarrhea in early infancy, frequent vomiting and abdominal distension in early infancy |
| Neurology | Areflexia, ↓ deep proprioception, and ataxia are uncommon during childhood and there is no retinopathy |
| Biological (Fasting State) | |
| Lipids | In patients with a suggestive profile: |
| ↓ HDL and Nal TG are the most discriminative specificities of CRD. | |
| ↓↓ Total cholesterol and ↓↓ LDL: intensity of decrease only around 50% normal values | |
| Neuromuscular | ↑ (1.5-4N) CK discriminative but inconstant abnormalities for CRD |
| Blood Cell Count | Absence of acanthocytosis in infancy is more frequent in CRD than in AB or HB |
| Hepatic | Frequent and early but not specific ↑ (1.5-3N) AST and/or ALT, with normal GGT, bilirubin and alkaline phosphatase |
| Liposoluble vitamins | Unspecific decrease ↓↓↓ E is the most severe and only permanent vitamin deficiency even with supplementation, ↓↓ A, ↓ - Nal D, ↓ - Nal K |
| Coagulation | ↓ - Nal INR. Decreased INR if there is vitamin K deficiency |
| Plasma fatty acid | Abnormal profile, omega 6 linoleic acid deficiency, normal omega 3 |
| Fasting lipids in parents | Nal |
| Oral Fat Load | |
| TGs are normal at baseline but do not increase postprandially and lack of change in low HDL after fat load | |
| Upper Endoscopy (fasting state or after enriched fat diet for 3 days) | |
| Unspecific white duodenal mucosa | |
| Optic microscopy | Villi are normal but the enterocytes are grossly distended by lipid droplets |
| Electron microscopy | Chylomicron-like aggregates, membrane bound? |
| Genotyping | |
| Mutations in SAR1B, Chromosome 5 | |
| Summary | |
| 1) Chronic diarrhea in young infants (< 6 Mo). Normal TG with decreased total cholesterol, LDL-C and HDL-C | |
| 2) Failure to thrive | |
| 3) White duodenal mucosa at endoscopy→ genetic hypocholesterolemia? | |
| 4) Genetic mutation of SAR1B → CRD confirmed | |
ALT, alanine aminotransferase; AST, aspartate aminotransferase; GGT, gamma-glutamyltranspeptidase; HDL-C, high-density lipoprotein-cholesterol; LDL-C, low-density lipoprotein-cholesterol; TG, triglycerides; INR, international normalized ratio; Nal, Normal