Prenatal Microarray Incidentally Diagnoses a Novel Inherited NF1 Intragenic Duplication.
Rhiannon Sandow, Gunjan Garg
✦ AI-curated · Sources linked
Case in brief
A woman with an undisclosed clinical diagnosis of NF1, lost to follow-up as a teenager, received a molecular diagnosis after prenatal chromosome microarray was performed because first-trimester screening indicated a high probability of trisomy 21. The microarray incidentally identified a 17q11.2 duplication; RNA analysis confirmed that a partial NF1 gene duplication was pathogenic. Her son, who also carried the duplication, presented neonatally with isolated tibial pseudoarthrosis. The mother had childhood café-au-lait macules and bilateral axillary freckling, followed later by a left forearm subcutaneous lipoma, illustrating differing NF1 features within the family.
What made this case unusual
The pathogenic partial NF1 duplication was identified incidentally on prenatal microarray, and the mother and son had differing clinical presentations: the son’s isolated tibial pseudoarthrosis contrasted with the mother’s more common pigmentary features and later lipoma.
Diagnostic / clinical pearl
An unexpected prenatal microarray finding may reveal an inherited condition; clinical genetics referral and careful medical and family history assessment are important for interpreting such results.
Why it matters
The case also underscores the relevance of pre-test counseling and informed consent when prenatal testing may uncover findings unrelated to the original indication.