Effects of long-term growth hormone therapy in a girl with Floating-Harbor syndrome

Abstract

Floating-Harbor syndrome is a rare autosomal dominant disorder that presents with short stature, facial dysmorphism, significantly delayed bone age, skeletal abnormalities, speech and language problems, and intellectual disabilities. Although short stature is one of the main clinical manifestations, use of growth hormone therapy in Floating-Harbor syndrome patients has been limited. Only a few reports have investigated the response to growth hormone therapy with regard to final adult height. We report the case of a 7-year-old girl with FloatingHarbor syndrome and a heterozygous mutation, c.7330C > T (p.Arg2444*), in the SRCAP gene. The patient exhibited dysmorphic facial features, severe intellectual disabilities, obsessive-compulsive and aggressive behaviors, and short stature without growth hormone deficiency. Her height standard deviation score improved after 55 months of growth hormone therapy.

Keywords: Growth hormone; Pediatric; SRCAP; Floating-Harbor syndrome.

Fig. 1.

(A) An X-ray of the hands of a 9-year-old patient displaying Floating-Harbor syndrome characteristics. Middle phalangeal hypoplasia, clinodactyly of the fifth finger, and hypoplastic metacarpals of the first finger are noted in both hands. Absence of a lunate and a hypoplastic scaphoid are shown bilaterally. (B) An X-ray of the legs of an 11-year-old patient with Floating-Harbor syndrome. Genu varum can be observed in the lower extremities bilaterally.

Fig. 2.

A schematic structure of the SRCAP gene and the locations of mutations detected in Floating-Harbor syndrome patients. All mutations (arrowhead) were truncating and located on exons 33 and 34 except for a single splicing mutation (No. 1) located on the first intron. Arrowheads denote mutation sites of all cases in the literature (No. 1–23 listed in Table 1) according to the order of genomic sequences. Red bars indicate the clustered region of mutations. The specific mutation (c.7330C >T, p.Arg2444*) of the patient in this study was located at a mutational hotspot (exon 34, red arrowhead).

Fig. 3.

Growth curve of our Floating-Harbor syndrome patient during growth hormone therapy. The red arrows indicate when our patient began growth hormone therapy, and the results were achieved after 55 months of treatment. GH, growth hormone; SDS, standard deviation score.

Fig. 4.

Bone age progression in our Floating-Harbor syndrome patient during growth hormone therapy. Changes in bone age at the chronologic age of 7.6 years (A), 9.6 years (B), 12.3 years (C), and 12.9 years (D).