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With sleuth work, pediatricians can identify genetic disorders


 

FROM AAP 2022

Jennifer Kalish, MD, PhD, fields as many as 10 inquiries a month from pediatricians who spot an unusual feature during a clinical exam, and wonder if they should refer the family to a geneticist.

“There are hundreds of rare disorders, and for a pediatrician, they can be hard to recognize,” Dr. Kalish said. “That’s why we’re here as geneticists – to partner so that we can help.”

Pediatricians play a key role in spotting signs of rare genetic diseases, but may need guidance for recognizing the more subtle presentations of a disorder, according to Dr. Kalish, a geneticist and director of the Beckwith-Wiedemann Syndrome Clinic at Children’s Hospital of Philadelphia, who spoke at the American Academy of Pediatrics National Conference.

Spectrums of disease

Pediatricians may struggle with deciding whether to make a referral, in part because genetic syndromes “do not always look like the textbook,” she said.

With many conditions, “we’re starting to understand that there’s really a spectrum of how affected versus less affected one can be,” by genetic and epigenetic changes, which have led to recognition that many cases are more subtle and harder to diagnose, she said.

Beckwith-Wiedemann syndrome is a prime example. The overgrowth disorder affects an estimated 1 in 10,340 infants, and is associated with a heightened risk of Wilms tumors, a form of kidney cancer, and hepatoblastomas. Children diagnosed with these conditions typically undergo frequent screenings to detect tumors to jumpstart treatment.

Some researchers believe Beckwith-Wiedemann syndrome is underdiagnosed because it can present in many different ways because of variations in the distributions of affected cells in the body, known as mosaicism.

To address the complexity, Dr. Kalish guided development of a scoring system for determining whether molecular testing is warranted. Primary features such as an enlarged tongue and lateralized overgrowth carry more points, whereas suggestive features like ear creases or large birth weight carry fewer points.

Diagnostic advances have occurred for other syndromes, as well. For example, researchers have created a scoring system for Russell-Silver syndrome, a less common disorder characterized by slow growth before and after birth, in which mosaicism is also present.

Early diagnosis and intervention of Russell-Silver syndrome can ensure that patients grow to their maximum potential and address problems such as feeding issues.

Spotting a “compilation of features”

Although tools are available, Dr. Kalish said pediatricians don’t need to make a diagnosis, and instead can refer patients to a geneticist after recognizing clinical features that hint at a genetic etiology.

For pediatricians, the process of deciding whether to refer a patient to a geneticist may entail ruling out nongenetic causes, considering patient and family history, and ultimately deciding whether there is a “compilation of features” that falls outside the norm, she said. Unfortunately, she added, there’s “not a simple list I could just hand out saying, ‘If you see these things, call me.’ ”

Dr. Kalish said pediatricians should be aware that two children with similar features can have different syndromes. She presented case studies of two infants, who both had enlarged tongues and older mothers.

One child had hallmarks that pointed to Beckwith-Wiedemann syndrome: conception with in vitro fertilization, length in the 98th percentile, a long umbilical cord, nevus simplex birthmarks, and labial and leg asymmetry.

The other baby had features aligned with Down syndrome: a heart murmur, upward slanting eyes, and a single crease on the palm.

In some cases, isolated features such as the shape, slant, or spacing of eyes, or the presence of creases on the ears, may simply be familial or inherited traits, Dr. Kalish said.

She noted that “there’s been a lot of work in genetics in the past few years to show what syndromes look like” in diverse populations. The American Journal of Medical Genetics Part A has published a series of reports on the topic.

Dr. Kalish reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

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