Can Obsessive-Compulsive Behaviors Be a Sign of a Rare Genetic Disorder?

What you need to know

• Obsessive-compulsive behaviors can sometimes be a sign of a rare genetic disorder called X-linked adrenoleukodystrophy (X-ALD).
• X-ALD can affect adults and may initially present with psychiatric symptoms before physical symptoms appear.
• Brain imaging and genetic testing can help diagnose X-ALD in patients with unexplained psychiatric or neurological symptoms.

Understanding X-linked Adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a rare genetic disorder that primarily affects the nervous system and adrenal glands. The term “X-linked” means that the disorder is caused by a gene located on the X chromosome, one of the sex chromosomes. As a result, X-ALD mostly affects males, while females can be carriers of the gene mutation.

In this disorder, there is a problem with breaking down certain types of fats called very long-chain fatty acids (VLCFAs). These fats build up in the body, particularly in the brain and adrenal glands, causing damage over time.

X-ALD can manifest in different ways and at different ages. While it’s often thought of as a childhood disorder, there is also an adult-onset form of the disease. This adult form can be particularly challenging to diagnose because its initial symptoms may be subtle or mimic other conditions.

A Surprising Presentation: OCD as the First Sign

In the case described by the researchers, a 35-year-old man developed obsessive-compulsive disorder (OCD) symptoms, particularly excessive hand washing. These symptoms had been present for five years before he was evaluated.

OCD is a mental health condition characterized by persistent, intrusive thoughts (obsessions) and repetitive behaviors or mental acts (compulsions) that a person feels compelled to perform to relieve anxiety. While OCD is typically considered a psychiatric disorder, this case highlights how it can sometimes be a sign of an underlying neurological condition.

The man’s family history provided an important clue. There was a pattern of X-ALD affecting male relatives across three generations, involving both childhood-onset and adult-onset cases. This family history prompted the doctors to consider X-ALD as a possible diagnosis, even though the patient’s initial symptoms were psychiatric rather than neurological.

From Psychiatric to Physical Symptoms

When the doctors examined the patient, they found some subtle neurological signs that aren’t typically associated with OCD. The patient had overactive reflexes throughout his body (described as “global brisk tendon reflexes”) and a positive Babinski sign on both sides.

The Babinski sign is a neurological test where the doctor strokes the sole of the foot. In adults, the toes should curl downward in response. If the big toe moves upward instead (a positive Babinski sign), it can indicate a problem with the brain or spinal cord.

These physical examination findings suggested that there was more going on than just OCD. They pointed to some involvement of the patient’s nervous system, consistent with the possibility of X-ALD.

The Role of Brain Imaging

To investigate further, the doctors performed brain imaging studies. They found abnormalities in the white matter of the brain, particularly around the ventricles (the fluid-filled spaces in the brain).

White matter is made up of nerve fibers that connect different parts of the brain. In X-ALD, the buildup of very long-chain fatty acids can damage this white matter, leading to the kind of changes seen on this patient’s brain scans.

These imaging findings were another piece of evidence pointing towards X-ALD as the underlying cause of the patient’s symptoms.

Confirming the Diagnosis

To definitively diagnose X-ALD, two key tests were performed:

1. Blood test for very long-chain fatty acids: The patient’s blood showed high levels of these fats, which is characteristic of X-ALD.

2. Genetic testing: Analysis of the patient’s DNA revealed a mutation in the ABCD1 gene. This gene provides instructions for making a protein that helps break down very long-chain fatty acids. Mutations in this gene are what cause X-ALD.

These tests confirmed that the patient indeed had adult-onset cerebral X-ALD, explaining both his psychiatric symptoms and the subtle neurological findings.

The Importance of This Case

This case report highlights several important points:

1. Psychiatric symptoms can sometimes be the first sign of a neurological disorder. In this case, OCD-like symptoms were the initial manifestation of X-ALD.

2. Adult-onset X-ALD can present differently from the childhood form. While childhood X-ALD often causes severe neurological symptoms early on, the adult form can have a more subtle onset.

3. Family history is crucial. The pattern of X-ALD in this patient’s family was a key clue that led to the correct diagnosis.

4. A combination of clinical examination, imaging, and laboratory tests may be necessary to diagnose complex conditions like X-ALD.

5. Genetic testing can provide a definitive diagnosis in cases of suspected inherited disorders.

Implications for Patients and Families

For patients experiencing persistent psychiatric symptoms, especially if there’s a family history of neurological disorders, it may be worth discussing the possibility of underlying medical causes with a healthcare provider. While most cases of OCD are not caused by genetic disorders like X-ALD, being aware of this possibility can lead to earlier diagnosis and treatment in the rare cases where it does occur.

For families with a history of X-ALD, it’s important to be aware that the disorder can manifest in different ways, including with psychiatric symptoms. Sharing detailed family medical history with healthcare providers can aid in faster, more accurate diagnoses.

Conclusions

• Obsessive-compulsive behaviors can sometimes be an early sign of adult-onset X-linked adrenoleukodystrophy (X-ALD).
• A combination of family history, physical examination, brain imaging, and genetic testing can help diagnose X-ALD.
• For patients with persistent psychiatric symptoms and a family history of neurological disorders, discussing the possibility of underlying medical causes with a healthcare provider may be beneficial.