Clinical and mutation analysis of a case of Noonan-like syndrome with loose anagen hair / 中华皮肤科杂志

To report a case of Noonan-like syndrome with loose anagen hair, and to detect gene mutations in the family. A 3-year-old female patient presented with a special facial appearance, short stature, deep palmar and plantar creases, and dark skin. The scalp hair was sparse and thin, dermoscopy showed black spot sign, single-hair follicular units, hair shafts varying in the diameter, upright hair and new vellus hair, and constriction of hair shafts and nodular hair were occasionally observed. Peripheral blood samples were collected from the proband and her parents, and the genomic DNA was extracted for whole-exome sequencing. A heterozygous missense mutation c.4A>G was identified in exon 2 of the SHOC2 gene in the proband, resulting in the substitution of serine by glycine at amino acid position 2 (p.S2G) . The mutation was not identified in either of her parents. Combined with the clinical phenotype and gene mutation, the diagnosis of Noonan-like syndrome with loose anagen hair was confirmed.

Características clínicas y genéticas de un paciente con síndrome de Noonan y una mutación de novo en el gen MAP2K1: Reporte de caso

Introducción: El síndrome de Noonan es un trastorno genético relacionado principalmente con la mutación del gen PTPN11. Reporte del caso: Recién nacido varón de 34 semanas de edad gestacional con ultrasonidos obstétricos que muestran higroma quístico, hidronefrosis renal bilateral, y polihidramnios. Al nacimiento, presentó edema nucal, puente nasal ancho, pabellón auricular de implantación baja, y criptorquidia derecha. Además, defecto del tabique auricular, ausencia de vena cava inferior, hipertensión pulmonar, conducto arterioso persistente y dificultad respiratoria. El resultado del análisis del panel de 14 genes mostró una mutación del gen MAP2K1 y una variante de significado incierto en el gen CBL, confirmando el diagnóstico del síndrome de Noonan negativo para PTPN11. Durante el seguimiento, también se le diagnosticó blefaroptosis izquierda y reflujo gastroesofágico. Conclusión: El presente caso destaca la amplia variedad de características fenotípicas en un paciente con síndrome de Noonan, con sospecha al nacimiento y confirmado durante el seguimiento.

Background: Noonan syndrome is a genetic disorder mostly related to PTPN11 gene mutation. Report Case: Newborn male of 34 weeks of gestational age with obstetric ultrasounds showing cystic hygroma, bilateral renal hydronephrosis, and polyhydramnios. At born, he presented nuchal edema, wide nose, low-set ears, and right cryptorchidism. Additionally, he presented atrial septum defect, absence of inferior vena cava, mild pulmonary hypertension, persistent ductus arteriosus, and respiratory distress. The result of the 14-gene panel analysis showed a MAP2K1 gene mutation and a variation of uncertain significance in the CBL gene, confirming the diagnosis of PTPN11- negative Noonan syndrome. During the follow-up, he was additionally diagnosed with blepharoptosis of left eye and gastroesophageal reflux disease. Conclusion:This report highlights the wide variety of phenotypical characteristics in a Noonan syndrome patient, which was suspected upon birth and developed during the follow-up.