Case Report Describes Rare Case of Newborn Diagnosed With CLN2 Disease

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by Patricia Inacio PhD |

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Newborn diagnosis

A case report has described a rare case of a newborn diagnosed with CLN2 disease, or late infantile Batten disease, after a genetic analysis confirmed a disease-causing mutation in the TPP1 gene.

The case-study, “A Case with Neonatal-onset Type 2 Neuronal Ceroid Lipofuscinosis: A Novel Mutation,” was published in the Journal of the College of Physicians and Surgeons Pakistan.

Neuronal ceroid lipofuscinosis type 2, or CLN2 disease, is a rare neurodegenerative disorder caused by mutations in the TPP1 gene, which provides instructions to make an enzyme called tripeptidyl peptidase 1 (TPP1). Mutations affecting the enzyme’s function cause cells, especially nerve cells, to accumulate waste products, which triggers the onset of disease.

The onset of CLN2 disease typically occurs between 2–4 years of age, with first symptoms including seizures and loss of motor, language and cognitive skills.

In this case report, researchers described a rare case of a newborn with CLN2 disease.

The boy was admitted to the neonatal intensive care unit of the İzmir Tepecik Training and Research Hospital, in Turkey, at 26 days of age with a diagnosis of metabolic disease.

The baby was born by C-section with a weight of 2.605 kilograms (5.7 pounds) at 38 weeks of gestation. The 39-year-old mother reported a reduction of baby movements during the pregnancy. The parents had no consanguinity (blood relation) and had a healthy daughter.

At examination, the baby weighed 2.330 kilograms (5.1 pounds), 42 centimeters (16.5 inches) in length and a head circumference of 29 centimeters (11.4 inches), which is below the third percentile. Percentiles are a measurement tool that can show where children are in comparison to others; the higher the percentile, the bigger the child is compared to others of the same sex and age.

Doctors intubated him. He was hypotonic (low muscle tone) and was without newborn reflexes.

An MRI of the baby’s brain showed severe shrinkage (atrophy) and suboptimal levels of myelin — the fat-rich substance that insulates nerve fibers — in both sides (hemispheres) of the brain and in the cerebellum (the brain’s center for motor coordination).

Further examination revealed a lack of myopathic discharge (electrical signals that cause muscle contraction) with no involvement of primary muscle fibers. A muscle biopsy also was found normal.

Genetic analysis identified a new disease-causing mutation (c.1145G> A) in both alleles (the two versions of a gene) of the TPP1. No mutations linked to spinal muscular atrophy (SMA), a genetic disease characterized by muscle weakness and wasting (atrophy), were found.

“To our knowledge, this mutation is novel and yet not reported in the literature,” the researchers wrote.

The baby was diagnosed with CLN2 disease and died before completing 5 months of age. “With this case, it should be kept in mind that NCL may rarely start early in newborns,” the researchers wrote.

Both parents and his sister carried the same TPP1 mutation, but in only one of the gene’s alleles, and were advised to undergo genetic counseling for subsequent pregnancies.

“In the presence of cerebral and cerebellar atrophy, NCL [neuronal ceroid lipofuscinoses] should be considered for early diagnosis and maybe for total curative treatment in the future,” the researchers concluded.