Monosomy 9p

Psychomotor developmental delays are delays in the emergence of the psychomotor skills that naturally develop from birth through adolescence, including cognitive, emotional, motor, language, and social skills. The severity of these delays can vary.{{cite book |doi=10.1016/B978-0-444-52891-9.00001-4 |chapter=Normal psychomotor development |title=Pediatric Neurology Part I |series=Handbook of Clinical Neurology |year=2013 |last1=Cioni |first1=Giovanni |last2=Sgandurra |first2=Giuseppina |volume=111 |pages=3–15 |pmid=23622146 |isbn=978-0-444-52891-9 }}{{Cite web|title=Psychomotor Development Retardation (PDR) {{!}} Rainbowkids Adoption & Child Welfare Advocacy|url=http://www.rainbowkids.com/special-needs/developmental-needs/psychomotor-development-retardation-pdr|access-date=2021-04-26|website=RainbowKids.com|language=en-us}}

Facial dysmorphisms are abnormalities in facial structure, including a sloping forehead, a prominent protruding forehead, hemifacial microsomia (in which one side of the face is underdeveloped), and otocephaly (an absence of the mandible and a fusion of the ears under the chin).{{cite journal |last1=Eixarch |first1=Elisenda |last2=Figueras |first2=Francesc |last3=Gómez |first3=Olga |last4=Puerto |first4=Bienvenido |title=Facial Dysmorphism |journal=Obstetric Imaging: Fetal Diagnosis and Care |date=2018 |pages=327–331.e1 |doi=10.1016/B978-0-323-44548-1.00069-3 |isbn=978-0-323-44548-1 }}{{Cite web |title=Chromosome 9, Partial Monosomy 9p - Symptoms, Causes, Treatment {{!}} NORD |url=https://rarediseases.org/rare-diseases/chromosome-9-partial-monosomy-9p/ |access-date=2024-01-13 |website=rarediseases.org |language=en-US}}

Congenital limb defects are the result of altered development of a fetus's upper or lower limb, including absence of the limb, a failure of portions of the limb (commonly fingers and toes) to separate, duplication of digits, overgrowth, or undergrowth.{{Cite web|title=Congenital Limb Defects {{!}} Boston Children's Hospital|url=https://www.childrenshospital.org/conditions-and-treatments/conditions/c/congenital-limb-defects|access-date=2021-04-26|website=www.childrenshospital.org|archive-date=2021-04-26|archive-url=https://web.archive.org/web/20210426151835/https://www.childrenshospital.org/conditions-and-treatments/conditions/c/congenital-limb-defects|url-status=dead}}

The inheritance pattern for monosomy 9p is inherited in an autosomal dominant inheritance pattern. This means that a single copy of the deletion is sufficient to cause the disease.{{Cite web|title=Chromosome 9p deletion syndrome - Conditions - GTR - NCBI|url=https://www.ncbi.nlm.nih.gov/gtr/conditions/C0795830/|access-date=2021-05-01|website=www.ncbi.nlm.nih.gov}}

The mutation, which occurs in the form of a deletion of the short arm of chromosome 9, causes the cell to not express the gene products normally controlled by the genes within the chromosome 9 deletion.{{Cite web|title=What is 9p Minus?|url=https://www.9pminus.org/what-is-9p-minus|access-date=2021-05-01|website=www.9pminus.org|language=en}}

The 9p deletion causes a loss of genes that would normally be there. The signs, symptoms and severity of the condition depend on the specific genes that are lost. Most of the genes involved are associated with the development of tissues.{{cite journal |last1=Climent Alcalá |first1=F.J. |last2=Molina Rodríguez |first2=M.A. |last3=González Casado |first3=I. |last4=Osona Bris |first4=L. |last5=Salamanca Fresno |first5=L. |last6=Guerrero-Fernández |first6=J. |last7=Martínez-Frías |first7=M.L. |last8=Gracia Bouthelier |first8=R. |title=Deleción 9p-. Disgenesia gonadal asociada a retraso mental e hipoplasia del cuerpo calloso. ¿Síndrome de genes contiguos? |trans-title=Chromosome 9P deletion: Gonadal dysgenesis associated with mental retardation and hypoplasia of the corpus callosum: A contiguous gene syndrome? |language=es |journal=Anales de Pediatría |date=March 2010 |volume=72 |issue=3 |pages=210–214 |doi=10.1016/j.anpedi.2009.10.018 |pmid=20138017 }}

There are many possible genes that can be deleted, but two particular genes, DMRT1 and DMRT2, are known to be involved. When DMRT1 and DMRT2 are deleted, genital malformations and mental retardation are evident, but the direct mechanisms for these problems remain undefined.

Geneticists originally had the syndrome narrowed down to the short arm region of chromosome 9. Now, the location of the deletion has recently been narrowed to 9p22.2-p23.

Diagnoses can occur at any age. Most of the time chromosome 9p deletion syndrome is diagnosed after birth by the detection of symptoms via clinical evaluation. Common methods used to detect monosomy 9p after birth include the use of a stethoscope, X-ray, and EKG. Monosomy 9p is also diagnosed before birth by ultrasound, amniocentesis, and chorionic villus sampling (CVS). Ultrasound can hint at the malformations of the face, limbs, and heart, while amniocentesis and CVS both use fluid and tissue to perform chromosomal studies to identify chromosomal abnormalities. Finally, karyotyping, a procedure used to examine a patient's chromosomes, can be used to diagnose monosomy 9p both before birth and after birth.{{cn|date=July 2022}}

Treatment of monosomy 9p focuses mainly on fixing the malformations. For example, to fix facial malformations, physicians can perform facial surgery to repair the facial malformations. This can open airways for the infant or patient, especially the nose-to-throat pathway. Similarly, to fix heart malformations, physicians can recommend surgery or medication to improve the efficiency of the pumping of the heart. Lastly remedial education, speech therapy, and physical therapy can be used to improve the developmental delay associated with the syndrome.

Monosomy 9p occurs 1 in 50,000 births.{{Cite web|title=What is 9p Minus?|url=https://www.9pminus.org/what-is-9p-minus|access-date=2021-04-26|website=www.9pminus.org|language=en}} Half of the cases occur sporadically, while the other half of the cases result from parent translocations or the parent having deletion as well.

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{{Medical resources

| DiseasesDB =

| ICD10 = Q93.5

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| ICDO =

| OMIM = 158170

| MedlinePlus =

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| MeshID = C538024

| Orphanet = 261112

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{{Chromosomal abnormalities}}

Category:Autosomal monosomies and deletions