Unusual phenotypic features in a patient with a novel splice mutation in the GHRHR gene.
Isolated growth hormone deficiency (IGHD) may be of genetic origin. One of the few genes involved in that condition encodes the growth hormone releasing hormone receptor (GHRHR) that, through its ligand (GHRH), plays a pivotal role in the GH synthesis and secretion by the pituitary. Our objective is to describe the phenotype of two siblings born to a consanguineous union presenting with short stature (IGHD) and Magnetic Resonance Imaging (MRI) abnormalities, and to identify the molecular basis of this condition. Our main outcome measures were clinical and endocrinological investigations, MRI of the pituitary region, study of the GHRHR gene sequence and transcripts. In both patients, the severe growth retardation (-5SD) was combined with anterior pituitary hypoplasia. In addition to these classical phenotypic features for IGHD, one of the patients had a Chiari I malformation, an arachnoid cyst, and a dysmorphic anterior pituitary. A homozygous sequence variation in the consensus donor splice site of intron 1 (IVS1 + 2T > G) of the GHRHR gene was identified in both patients. Using in vitro transcription assay, we showed that this mutation results in abnormal splicing of GHRHR transcripts. In this report, which broadens the phenotype associated with GHRHR defects, we discuss the possible role of the GHRHR in the proper development of extrapituitary structures, through a mechanism that could be direct or secondary to severe GH deficiency.
Hilal
Latifa
L
Laboratoire de Génétique et de Physiologie Neuroendocrinienne, Equipe des Bases Moléculaires de Maladies Génétiques, UFR de Génétique et Biologie Moléculaire, Université Ibn Tofaïl, Faculté des Sciences, Kenitra, Maroc.
Hajaji
Yassir
Y
Vie-Luton
Marie-Pierre
MP
Ajaltouni
Zeina
Z
Benazzouz
Bouchra
B
Chana
Maha
M
Chraïbi
Adelmajid
A
Kadiri
Abdelkrim
A
Amselem
Serge
S
Sobrier
Marie-Laure
ML
D017398:Alternative Splicing; D002648:Child; D004252:DNA Mutational Analysis; D004393:Dwarfism, Pituitary / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D005260:Female; D013006:Growth Hormone / Q000627:therapeutic use; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D022821:RNA Splice Sites / Q000235:genetics*; D018013:Receptors, Neuropeptide / Q000235:genetics* / Q000502:physiology; D018017:Receptors, Pituitary Hormone-Regulating Hormone / Q000235:genetics* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D022821:RNA Splice Sites; D018013:Receptors, Neuropeptide; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D013006:Growth Hormone; C048250:somatotropin releasing hormone receptor