Short stature and mild developmental delay in a child with partial duplication of DIAPH2 gene: good response to recombinant Growth Hormone therapy: A Case Report

Sohair Elsiddig; Noor Hamed; Ashraf Soliman

Introduction: The DIAPH2 gene (Diaphanous homolog 2 Drosophila) is a Protein Coding gene found on the long arm of the X chromosome and is a member of the FH1/FH2 protein family. Members of this family affect cytokinesis and other actin-mediated morphogenetic processes required in early gonadal development.

Case Description: An eight-year-old girl was referred with a chief complaint of short stature. She is a product of normal vaginal delivery term with a birth weight of 2.2 kg. Her slow growth was noted at the age of 5 years. She had delayed speech development and mild intellectual disability. Measurements showed microcephaly (HCSDS= -3.5), short stature (HtSDS -3.5), and underweight (WtSDS = -2.5). Mid parental height SDS was 0.5. She had down slanting eyes, a round face, full cheeks, a short neck, and a shield chest. She was prepubertal. Investigation showed normal hemogram, liver and renal function tests, and thyroid function. Bone age corresponded to her age. Her IGF-1SDS = -1.3 and peak GH level after clonidine stimulation was 15 ng/mL. US Pelvis showed: Uterus is 10.2 x 5.4 mm. Right ovary measures 3.6.cc (3.3 x 1.9 x 1.0 cm) with multiple follicles seen and the left ovary measured 1 cc (1.7 x 1.6 x 0.6 cm). Microarray analysis revealed a gain of ~422-kb of the long arm of chromosome X within cytogenetic band Xq21. The copy number change results in partial duplication of the DIAPH2 gene. She was started on rhGH therapy, (Somatropin 0.05mg/kg/d) and oral nutritional supplements. Eighteen-month follow-up showed a good response to GH therapy. She gained 1.7 SD in HtSDS and 1 SD in WtSDS. (Table)

Child growth parameters responded to GH therapy as following
	At presentation	6 months follow up	18 months follow up
HtSDS	-3.5	-3.16	-1.8
Ht. Velocity	5 cm / year	4 cm / 6 months	10 cm/ year
WtSDS	-2.5	-2.2	-1.8
WGD	1.8 g/d	9g/d	7g/d
BMISDS	0	-0.4	-0.8
IGF-1SDS	-1.3	---	0
Bone age SDS	0	---	0

Discussion: Literature reported few cases with GH deficiency (GHD) associated with Xq duplication, but all were associated with hypothyroidism or empty sella. Our patient had dysmorphic features, microcephaly, congenital heart disease, and normal GH secretion. Her HtSDS increased by 1.7 SD after starting rhGH therapy.

Conclusion: Female patients with duplication in Xq had growth retardation, after checking the GH-IGF1 axis, a trial of rhGH therapy is warranted.

ESPE Abstracts

P2-167