A novel multimorbidity: co-occurrence of neonatal diabetes mellitus and leukocyte adhesion deficiency type 1 in two siblings.
Ilkyaz Turktan, Zehra Sule Haskologlu, Tugba Kontbay Cetin et al.
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Case in brief
Two sisters born to consanguineous parents had permanent neonatal diabetes mellitus and leukocyte adhesion deficiency type 1 (LAD-1). Both carried homozygous variants in the INS promoter (c.-331C>G) and ITGB2 (c.388T>C). The first sister developed hyperglycemia on postnatal day 14 and had meningomyelocele, developmental hip dislocation, recurrent infections, and decreased leukocyte CD18 expression. The second developed hyperglycemia on day 2 and had delayed umbilical cord separation, leukocytosis, and absent CD18 expression. These findings supported both diagnoses in each sibling; the abstract does not report subsequent clinical outcomes.
What made this case unusual
The reported combination of neonatal diabetes mellitus and LAD-1 occurred in two siblings; the authors state that this coexistence had not previously been reported.
Diagnostic / clinical pearl
When one genetic diagnosis does not account for a complex phenotype, consider an additional disorder. In these siblings, diabetes coexisted with infection-related or other clinical clues and abnormal CD18 expression supporting LAD-1.
Why it matters
Recognizing multiple genetic diagnoses in a consanguineous family can inform genetic counseling and long-term management.