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Query: EC:2.7.10.1 (
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We report on the clinical and molecular findings in 25 males and three females with Kallmann syndrome (KS) aged 10-53 yr. Ten males were from five families, and the remaining 15 males and three females were apparently sporadic cases. Molecular studies were performed for Kallmann syndrome 1 (KAL1) and fibroblast growth factor receptor 1 (
FGFR1
, also known as KAL2) by sequence analysis for all the coding exons, by PCR-based deletion analysis, and by fluorescence in situ hybridization (FISH) analysis, showing six novel and two recurrent intragenic KAL1 mutations in seven familial and four sporadic male cases and two novel intragenic
FGFR1
mutations in two sporadic male cases. In addition, submicroscopic deletions at Xp22.3 involving VCX-A, STS, KAL1, and OA1 were identified in three familial cases and one sporadic male case affected by a contiguous gene syndrome. Clinical assessment in the 15 males with KAL1 mutations showed normal and borderline olfactory function in two males and right-side dominant renal lesion in seven males, in addition to variable degrees of
hypogonadotropic hypogonadism
(HH) in all the 15 males and olfactory dysfunction in 13 males. The two males with
FGFR1
mutations had HH and anosmia and lacked other features. Clinical features in the remaining 11 cases with no demonstrable KAL1 or
FGFR1
mutations included right renal aplasia in one female, cleft palate in one male, cleft palate and perceptive deafness in one male, and dental agenesis and perceptive deafness in one male, in addition to a variable extent of HH and olfactory dysfunction. The results suggest the following: 1) KAL1 mutations might be more prevalent in the Japanese patients than previously estimated in the Caucasian patients and can be associated with apparently normal olfactory function; 2)
FGFR1
mutations account for approximately 10% of KS patients, as previously reported in the Caucasian patients, and can result in HH and olfactory dysfunction-only phenotype; and 3) renal aplasia, which is characteristic of KAL1 mutations, and cleft palate and dental agenesis, which are characteristic of
FGFR1
mutations, can occur in patients without KAL1 and
FGFR1
mutations.
...
PMID:Clinical assessment and mutation analysis of Kallmann syndrome 1 (KAL1) and fibroblast growth factor receptor 1 (FGFR1, or KAL2) in five families and 18 sporadic patients. 1500 91
Kallmann syndrome (KAL) associates
hypogonadotropic hypogonadism
and anosmia, i.e. a deficiency of the sense of smell. Anosmia is related to the absence or the hypoplasia of the olfactory bulbs. Hypogonadism is due to GnRH deficiency, and is likely to result from the failed embryonic migration of GnRH-synthesizing neurons. These cells normally migrate from the olfactory epithelium to the forebrain along the olfactory nerve pathway. Kallmann syndrome is genetically heterogeneous. The gene responsible for the X-chromosome linked form of the disease, KAL-1, has been identified in 1991. KAL1 encodes a ~95 kDa glycoprotein of unknown function, which is present locally in various extracellular matrices during the period of organogenesis. The recent finding that
FGFR1
mutations are involved in an autosomal dominant form of Kallmann syndrome (KAL-2), combined to the analysis of mutant mouse embryos that no longer express Fgfr1 in the telencephalon, suggests that the disease results from a deficiency in FGF-signaling at the earliest stage of olfactory bulb morphogenesis. We propose that the role of the KAL1 gene product, the extracellular matrix protein anosmin-1, is to enhance FGF-signaling, and suggest that the gender difference in anosmin-1 dosage (because KAL1 partially escapes X-inactivation) explains the higher prevalence of the disease in males.
...
PMID:[Kallmann De Morsier syndrome: FGF-signaling insufficiency?]. 1536 47
Kallmann syndrome (KAL) is a developmental disease that combines
hypogonadotropic hypogonadism
and anosmia. Anosmia is related to the absence or hypoplasia of the olfactory bulbs. Hypogonadism is due to GnRH deficiency and is likely to result from the failed embryonic migration of GnRH-synthesizing neurons. These cells normally migrate from the olfactory epithelium to the forebrain along the olfactory nerve pathway. KAL is phenotypically and genetically heterogeneous. The gene responsible for the X-chromosome linked form of the disease (KAL1) has been identified in 1991. KAL1 encodes anosmin-1, an approximately 95-kDa glycoprotein of unknown function which is present locally in various extracellular matrices during the period of organogenesis. The recent finding that
FGFR1
mutations are involved in an autosomal dominant form of Kallmann syndrome (KAL2), combined with the analysis of mutant mouse embryos that no longer express Fgfr1 in the telencephalon, suggests that the disease results from a deficiency in FGF signaling at the earliest stage of olfactory bulb morphogenesis. We propose that the role of anosmin-1 is to enhance FGF signaling and suggest that the gender difference in anosmin-1 dose (because KAL1 partially escapes X-inactivation) explains the higher prevalence of the disease in males.
...
PMID:Kallmann syndrome: fibroblast growth factor signaling insufficiency? 1536 36
Kallmann syndrome (KAL) combines
hypogonadotropic hypogonadism
and anosmia. Hypogonadism is due to Gonadotropin Releasing Hormone (GnRH) deficiency and anosmia is related to hypoplasia of the olfactory bulbs. Occasional symptoms include renal agenesis, bimanual synkinesia, cleft lip palate, dental agenesis. KAL is genetically heterogeneous and two genes have so far been identified, namely KAL1 (Xp22.3) and
FGFR1
/KAL2 (8p12), which underlie the X chromosome-linked form and an autosomal dominant form of the disease, respectively. We studied a cohort of 98 unrelated Caucasian KAL patients. We identified KAL1 mutations in 14 patients, of which 7 (c.3G>A (p.M1?), g.IVS1+1G>T, c.570_571insA (p.R191fsX14), c.784G>C (p.R262P), c.958G>T (p.E320X), c.1651_1654delinsAGCT (p.P551_E552delinsSX), c.1711T>A (p.W571R)) have not been previously reported. In addition, we found
FGFR1
mutations in 7 patients, namely c.303G>A (p.V102I), C.385A>C (p.D129A), c.810G>A (p.V273M), c.1093_1094delAG (p.R365fsX41), c.1561G>A (p.A520T), c.1836_1837insT (p.Y613fsX42), c.2190C>G (p.Y730X), all of which were novel mutations. In this study, unilateral renal agenesis and bimanual synkinesia were exclusively found associated with KAL1mutations, cleft palate and dental agenesia with FGFR1mutations.
...
PMID:Kallmann syndrome: 14 novel mutations in KAL1 and FGFR1 (KAL2). 1560 12
Kallmann syndrome (KS) is a developmental disease that combines
hypogonadotropic hypogonadism
and anosmia/hyposmia. Other congenital abnormalities may also coexist. This present report describes two sisters, aged 13 and 12 years, born from Lebanese consanguineous parents. The two sisters have complete androgen insensitivity (normal female appearance and an XY karyotype) due to a novel mutation, a C-to-G transversion in intron 2 of the androgen receptor gene, resulting in an aberrant splicing leading to an insertion of 66 nucleotides in the mRNA. In addition, the older sister has KS, together with synkinesia and multiple skeletal abnormalities, mainly kyphosis, vertebral abnormalities, and short right hand and feet. Her testosterone, FSH and LH levels were very low compared with her younger sister. No mutation in the KAL1 and
FGFR1
/KAL2 genes were found. This unique report raises the possibility of an autosomal recessive or X-linked form of KS with new phenotypic expression.
...
PMID:Coexistence of Kallmann syndrome and complete androgen insensitivity in the same patient. 1594 19
DAX-1 is an unusual orphan nuclear receptor whose mutations cause adrenal hypoplasia congenita (AHC) associated with
hypogonadotropic hypogonadism
(
HHG
). Subcellular localization of DAX-1 is a critical determinant of its biological activity. Indeed, the missense mutants found in AHC patients have an impaired transcriptional repressor activity due to protein misfolding and shift of their localization to the cytoplasm. For this reason, we sought to identify factors that regulate DAX-1 subcellular localization. Of several stimuli and chemical compounds tested, heat shock was the only stimulus able to induce rapid and massive relocalization of DAX-1 in the cytoplasm. The heat shock effect is reversible and does not involve stimulation of the p38 and
ERK
pathways. Heat shock probably acts by inducing modifications of DAX-1 and increasing its partitioning in the insoluble cellular fraction.
...
PMID:Heat shock affects trafficking of DAX-1 by inducing its rapid and reversible cytoplasmic localization. 1638 85
Mutations in KAL1 and
FGFR1
cause Kallmann syndrome (KS), whereas mutations in the GNRHR and GPR54 genes cause idiopathic
hypogonadotropic hypogonadism
with normal olfaction (nIHH). Mixed pedigrees containing both KS and nIHH have also been described; however, the genetic cause of these rare cases is unknown. We examined the
FGFR1
gene in seven nIHH subjects who either belonged to a mixed pedigree (n = 5) or who had associated midline defects (n = 2). Heterozygous
FGFR1
mutations were found in three of seven unrelated nIHH probands with normal MRI of the olfactory system: (i) G237S in an nIHH female and a KS brother; (ii) (P722H and N724K) in an nIHH male missing two teeth and his mother with isolated hyposmia; and (iii) Q680X in a nIHH male with cleft lip/palate and missing teeth, his brother with nIHH, and his father with delayed puberty. We show that these mutations lead to receptor loss-of-function. The Q680X leads to an inactive
FGFR1
, which lacks a major portion of the tyrosine kinase domain (TKD). The G237S mutation inhibits proper folding of D2 of the
FGFR1
and likely leads to the loss of cell-surface expression of
FGFR1
. In contrast, the (P722H and N724K) double mutation causes structural perturbations in TKD, reducing the catalytic activity of TKD. We conclude that loss-of-function mutations in
FGFR1
cause nIHH with normal MRI of the olfactory system. These mutations also account for some of the mixed pedigrees, thus challenging the current idea that KS and nIHH are distinct entities.
...
PMID:Mutations in fibroblast growth factor receptor 1 cause both Kallmann syndrome and normosmic idiopathic hypogonadotropic hypogonadism. 1660 36
This study compares the relative effects of advancing male age on multiple genomic defects in human sperm [DNA fragmentation index (DFI), chromatin integrity, gene mutations, and numerical chromosomal abnormalities], characterizes the relationships among these defects and with semen quality, and estimates the incidence of susceptible individuals for a well characterized nonclinical nonsmoking group of 97 men (22-80 years). Adjusting for confounders, we found major associations between age and the frequencies of sperm with DFI and fibroblast growth factor receptor 3 gene (FGFR3) mutations associated with achondroplasia (P < 0.01) with no evidence for age thresholds. However, we found no associations between age and the frequencies of sperm with immature chromatin, aneuploidies/diploidies,
FGFR2
mutations (Apert syndrome), or sex ratio in this cohort. There were also no consistent correlations among genomic and semen-quality endpoints, except between DFI and sperm motility (r = -0.65, P < 0.001). These findings suggest there are multiple spermatogenic targets for genomically defective sperm with substantially variable susceptibilities to age. Our findings predict that as healthy males age, they have decreased pregnancy success with trends beginning in their early reproductive years, increased risk for producing offspring with achondroplasia mutations, and risk of fathering offspring with Apert syndrome that may vary across cohorts, but with no increased risk for fathering aneuploid offspring (Down,
Klinefelter
, Turner, triple X, and XYY syndromes) or triploid embryos. Our findings also suggest that the burden of genomic damage in sperm cannot be inferred from semen quality, and that a small fraction of men are at increased risk for transmitting multiple genetic and chromosomal defects.
...
PMID:Advancing age has differential effects on DNA damage, chromatin integrity, gene mutations, and aneuploidies in sperm. 1676 65
Kallmann syndrome (KS) is a developmental disease characterized by the association of isolated
hypogonadotropic hypogonadism
and anosmia/hyposmia. We report an unusual presentation of two females with KS and empty sella. These females, aged at 20 and 29-year-old, presented primary amenorrhea with prepubertal estradiol and low gonadotropin levels. No other significant clinical signs were observed. Empty sella was observed on MRI in both cases. Sequencing of
FGFR1
gene, recently implicated in autosomal form of KS, was performed and one splicing mutation (IVS14 + 1G > A) was identified in one patient.
...
PMID:Two cases of Kallmann syndrome associated with empty sella. 1753 Apr 15
Gonadotropin-releasing hormone (GnRH) and olfactory neurons migrate together from the olfactory placode, and GnRH neurons eventually reside in the hypothalamus. Hypogonadism in male infants may be diagnosed in the first 6 months of life but cannot be diagnosed during childhood until puberty occurs. Patients with low serum testosterone and low serum gonadotropin levels have idiopathic
hypogonadotropic hypogonadism
(IHH). Mutations in three genes (KAL1,
FGFR1
, and GNRHR) comprise most of the known genetic causes of IHH. Treatment with testosterone is indicated if fertility is not desired, whereas GnRH or gonadotropin treatment induces spermatogenesis and fertility.
...
PMID:Hypogonadotropic hypogonadism. 1754 19
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