Screening of MAMLD1 Mutations in 70 Children with 46,XY DSD: Identification and Functional Analysis of Two New Mutations

More than 50% of children with severe 46,XY disorders of sex development (DSD) do not have a definitive etiological diagnosis. Besides gonadal dysgenesis, defects in androgen biosynthesis, and abnormalities in androgen sensitivity, the Mastermind-like domain containing 1 (MAMLD1) gene, which was identified as critical for the development of male genitalia, may be implicated. The present study investigated whether MAMLD1 is implicated in cases of severe 46,XY DSD and whether routine sequencing of MAMLD1 should be performed in these patients

Isolated micropenis reveals partial androgen insensitivity syndrome confirmed by molecular analysis

Abstract Partial androgen insensitivity syndrome (PAIS) is the milder variant of androgen receptor (AR) defects. The subtle effects of AR mutations present in a patient with micropenis, peno-scrotal hypospadias, infertility, clitoromegaly and posterior labial fusion. We studied the association of isolated micropenis with the genetic defects resulting in androgen resistance, that is, AR gene defects and 5-α reductase type 2 (SRD5A2) deficiency. We describe two cases of isolated micropenis: one in a 14-year-old boy and the other in a 3-year-old boy who was followed until he was 10 years old. There were no findings of hypospadias, cryptorchidism or gynecomastia in either of these patients. Serum gonadotrophin and androgen levels were obtained and karyotyping was done. Human chorionic gonadotropin (hCG) stimulation testing assessed the functional capacity of the testes. DNA was extracted from peripheral leukocytes, and all exons of the SRD5A2 and AR genes were amplified by polymerase chain reaction and sequenced. In both patients, baseline testosterone (T) level was low and the values were elevated after hCG testing. The sequence of the SRD5A2 gene was normal in patient 1, and a heterozygous polymorphism, V89L, was found in patient 2. Two known mutations, P390S and A870V, were identified in patients 1 and 2, respectively. Mutations in the AR gene can be associated with isolated micropenis without other features of PAIS, such as hypospadias or gynecomastia. This underlines the importance of including AR gene analysis in the evaluation of isolated micropenis with normal plasma T to ensure proper management of the patient and appropriate genetic counseling for the family

Complete androgen insensitivity syndrome is frequently due to premature stop codons in exon 1 of the androgen receptor gene: an international collaborative report of 13 new mutations

Objective: To confirm the clinical diagnosis of complete androgen insensitivity syndrome (CAIS) by molecular genetic analysis and to determine the prevalence of exon 1 mutations in the androgen receptor (AR) transactivation defects of a large series of CAIS patients. Design: International retrospective study. Setting: University Hospital of Montpellier, Department of Hormonology. Patient(s): 105 patients with normal female external genitalia, bilateral intra-abdominal or inguinal testis, normal breast development, absent or sparse pubic hair, normal or high endogenous testosterone production, hypoplastic or absent wolffian structures, and 46,XY karyotype. Intervention(s): Sequencing of the AR gene. Main Outcome Measure(s): Prevalence of AR exon 1 mutations. Result(s): Over a 10-year period (1997 to 2007), we identified 78 AR gene mutations in 105 patients with CAIS; 21 of them were located in exon 1, and 13 of these were new mutations. We report 13 new mutations in the AR gene. All but one were stop codons, and the last was a splicing abnormality. Conclusion(s): The finding that 27% of the mutations in our cohort were localized in exon 1 versus 15% in previous works justifies the sequencing of this exon in patients with CAIS. (Fertil Steril(R) 2010;94:472-6. (C) 2010 by American Society for Reproductive Medicine.

Homology study showed that this amino acid was highly conserved through species for the c.1041C>A and c.1151C>T mutations.

<p>Homology study showed that this amino acid was highly conserved through species for the c.1041C>A and c.1151C>T mutations.</p

Clinical and hormonal data of patients with mutated <i>MAMLD1</i>.

<p>SD: standard deviation. ND: not determined. NA: not available. DHT: dihydrotestosterone. DHEA: dihydroepiandrsosterone. Parentheses indicate the standard deviation for height and weight and the normal range for hormone serum levels. Testes of 1–2 ml can be regarded as normal, as recently reported by Shibata et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032505#pone.0032505-Shibata1" target="_blank">[34]</a>.</p>*<p>It is notable that anti-mullerian hormone and inhibin were lowered in one case. <i>MAMLD1</i> is indeed reported to be expressed in Sertoli cells, as well <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032505#pone.0032505-Fukami1" target="_blank">[15]</a>.</p

Incidence of exonic polymorphisms p.P359S and p.N662S, and relative haplotypes in normal controls and 46,XY DSD patients.

<p>Controls are combined with the published series (matched for ethnicity of patients and controls) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032505#pone.0032505-Kalfa1" target="_blank">[13]</a><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032505#pone.0032505-Chen1" target="_blank">[14]</a>. The χ-square test was performed. When combining all patients with the p.662G polymorphism whatever the p.359 allele, this p.662G was significantly more frequent in 46,XY DSD patients: 27.1% (n = 19) vs. 6.8% (n = 40), <i>p</i> = 0.0001.</p

Tertiary structure prediction of the wildtype protein (left column) and with the mutants.

<p>3D structure was predicted at Protein Homology/analogY Recognition Engine (PhyreEngine) from the Structural Bioinformatics Group, Imperial College, London, at <a href="http:www.sbg.bio.ic.ac.uk/phyre~/" target="_blank">http:www.sbg.bio.ic.ac.uk/phyre~/</a>. The plain arrows show the changes in the shape of the protein between the wildtype and p.P384L.</p

Electrochromatograms and pedigrees of the three patients with <i>MAMLD1</i> mutations.

<p>The black squares indicate patients with posterior hypospadias. All mutant sequences were controlled by wildtype (WT) DNA. Regarding case 1's family, only the members III-3 and II-4 were genotyped, as the other members in the pedigree declined genetic testing.</p