I noticed her fingernails weren't growing, but I didn't realize that meant anything. Her hair started to fall out, but many babies lose the hair they were born with, so I didn't worry. She slept a lot, but she was still very little. She had a rash in the folds of her skin. I thought it was because she was so chubby. She made a strange wheezing noise when she ate. Again I didn't realize it meant anything.
By 6 weeks it was clear she waslethargic:
She continued to sleep all day... She would wake to eat, stare into space for a few minutes, then go back to sleep.
Sometime around 7 weeks, she began having seizures... So she was admitted to the hospital and given a battery of tests, all of which came back either negative or normal.
Click here to see the result in SimulConsult Diagnostic Decision Support with all the findings above combined together. Biotinidase deficiency is by far the leader.
She was discharged on phenobarbital but readmitted later for a more complete work-up:
The Neurologist who had been overseeing R's care called in geneticist. That day he recommended giving her 10mg of biotin a day while we waited for her blood test results to come back.... After just a day of Biotin treatment she was a different baby. She woke up. She no longer slept all day, she interacted with us, and in a couple of weeks, she began smiling.
No mention is made of whether the diagnosis was confirmed as biotinidase deficiency or was another disorder for which biotin is helpful such as holocarboxylase synthetase deficiency, but this would be a late presentation of holocarboxylase synthetase deficiency.
Note: as of the time the case was written up here, the SimulConsult Diagnostic Decision Support database does not include any information about hypoplastic fingernails in biotinidase deficiency, though brittle fingernails are described in biotin deficiency diseases. Such information would have elevated the probability of a biotinidase diagnosis in this case. If you know of such an association please contact us.
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If you know of interesting cases in the news, in journals or on open Web sites of hospitals or foundations, please contact us and include enough information for us to find the material. The differential diagnosis will change over time as people mull over the case and submit new information to the database about findings in the relevant diseases.