While genomic rearrangements of chromosome 17 are not uncommon, deletions of chromosome band 17q24.2-q24.3 are rare, and associated features include cardiac abnormalities, characteristic facial appearance, short stature, obesity, syndactyly, intellectual disability, seizures, delayed dentition, and features of Carney Complex. It has been suggested that the involvement of KCNJ2, PRKCA, CACNG gene cluster (CACNG1, CACNG4, CACNG5), and PRKAR1A genes contribute to this phenotype. A case of a child with a 3.7 Mb deletion at chromosome band 17q24.2-q24.3, as well as a 2.1 Mb gain at chromosome 17q22, is described.
A now 6 year old female was born at 34 weeks gestational age with prenatal course complicated by oligohydramnios and intrauterine growth restriction. Birth weight was at the 9th percentile, and birth length was at the 92nd percentile. She was noted to have a patent ductus arteriosus (PDA), poor suck and swallow, and dysmorphic features. Chromosome microarray revealed a 3.7 Mb deletion at Chromosome 17q24.2-q24.3, involving KCNJ2, PRKCA, CACNG gene cluster (CACNG1, CACNG4, CACNG5), and PRKAR1A, as well as a 2.1 Mb gain at Chromosome 17q22, involving C17orf112 and KIP2B.
At 6 years old, she continues to be small for weight (-4.5 SDs), BMI (-4.22 SDs), and height (-2.5 SDs), though with appropriate pre-pubertal linear growth velocity. She is minimally verbal and continues to receive physical, occupational and speech therapies. Examination showed dysmorphic facial features, including triangular face with pointed chin, prominent forehead with low-set ears, retro-micrognathia, almond-shaped eyes with up-slanting palpebral fissures, bulbous nose, thin lips, and irregularly-shaped teeth. She had bilateral 5th digit clinodactyly, tapering of the distal aspects of bilateral first digits of the hands, and syndactyly of bilateral 2nd/3rd digits of the feet. She had scant freckling over the nasal bridge and cheeks, as well as freckles of the left arm, left groin, and back. She had no clinical stigmata of hypercortisolism. Echocardiogram continues to show a PDA with no cardiac myxomas. Thyroid ultrasound was normal. However, she does have mild hypercalcemia, most recently 2.61 mmol/L (2.15-2.55), and mildly elevated alkaline phosphatase of 341 U/L (96-297).
This case highlights a child with many of the previously reported findings associated with 17q24.2-q24.3 deletions. However, she also was noted to have a 2.1 Mb gain at chromosome 17q22 involving C17orf112 and KIP2B genes, which have not yet been associated with a clinical phenotype. It is therefore unclear if her phenotype is partially explained by the chromosomal gain. Clinicians should suspect a contiguous gene deletion syndrome in a patient with Carney Complex and atypical features. Patients with this condition have also been described as “Carney Complex-plus”, a term that we do not recommend be used.