Story of a girl diagnosed with Encephalopathy, lethal, due to defective mitochondrial peroxisomal fission 1

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Beginning of the story

Hannah was born at 38 weeks of gestation to unrelated parents.

Hannah was born at 37 weeks of gestation to unrelated parents. She had two healthy siblings born before her.

Her delivery was done with a Caesarean section. At birth, she weighed 2.4kg, which is relatively small in size for a newborn.

Six months after birth

Six months after birth, Hannah had hard time eating, and was relatively small in size.

Six months after birth, Hannah and her parents visited her doctor’s office after she suffered from a cold.

She was having a hard time eating and was relatively small in size with a height of 56.3cm (under 3 percentile), weight of 6.5kg (under 10 percentile), and head circumference of 41cm (between 10 to 25 percentile).

Physical examination

With physical examination, doctor observed retrognathia & small chin, temporal narrowing, and developmental delay.

Hannah showed retrognathia, small chin, temporal narrowing. In other words, her chin was small and set further back than the upper jaw, and the temporal side of her chin was narrower than normal.

She was unable to control her head, roll over, and sit by herself, which was a typical sign of developmental delay.

Further tests conducted

Four additional tests - chromosomal array, karyotyping, mitochondrial gene sequencing and blood test - were conducted. The results were all normal.
Hannah had few other tests to learn more about her conditions.

Her blood test found an elevated lactic acid level, and arterial blood gas analysis(ABGA) found low HCO3- level, all to suspect metabolic acidosis. Her creatine kinase level was also elevated.

At the genomic level, karyotyping, chromosomal array, and mitochondrial gene sequencing were conducted. However, they all found to be normal.

Whole exome sequencing

Whole exome sequencing on Hannah found a de novo variant.
Even after various testing was conducted, it was difficult to get the results together and find the cause. Therefore, whole exome sequencing was conducted.

The test result has found a likely pathogenic variant(LP, following ACMG-AMP guidelines) on the DNM1L gene. The genetic variant was confirmed as a de novo variant after her parents tested.

Hannah's final diagnosis was 'Encephalopathy, lethal, due to defective mitochondrial peroxisomal fission 1 (EMPF 1).' To read details about the disease, visit Rare Disease Series #19: EMPF1.

After diagnosis

After diagnosis, Hannah was given multivitamin and L-carnitine treatment as a method of supportive care. However, the treatment did not have a positive impact on resolving her developmental delay. Her lactic acid level still remains high, and she is visiting the hospital for multiple febrile events.

Diagnosis

  1. ic_Disease-1
  2. Disease:
    Encephalopathy, lethal, due to defective mitochondrial peroxisomal fission 1 (MIM# 614388)
    Gene: DNM1L
Stay tuned for 3billion’s next 'My Odyssey' series. We will deliver more diagnostic stories of patients diagnosed with us. Thank you.